Caffeine has been shown to promote plant growth by stimulating cell division and elongation, leading to increased root and shoot development, resulting in healthier and more robust plants. However, there are mixed effects on plant growth, with some studies showing that caffeine initially has stable cell growth rates but can eventually kill or distort these cells, resulting in a dead or stunted plant.
A reduction in caffeine in coffee leaves and seeds may result in decreased ability against deterrence and an increase in pest pressure. Surprisingly, caffeine may even be mildly toxic to the plant producer, acting as a phosphodiesterase inhibitor. Some plants seem to benefit and grow faster when caffeine is added to the soil, while others seem to become stunted or grow slower.
In almost all cases, caffeine tends to inhibit plant germination and growth at a high enough level. However, exact results depend on the plant species and how and when the caffeine is used. The study found that drinks with more sugar died the fastest while those with water grew the best.
Sugary sodas do not aid in a plant’s development and can retard its growth. Some plants may reject caffeine in one of the forms chosen (coffee, energy drinks, and soda) as a way to grow faster due to the presence of other ingredients that may also affect plant growth.
Caffeine grounds are a versatile and sustainable fertiliser rich in nitrogen and other nutrients useful for improving soil structure, deterring pests, and improving soil structure. Experts at WeThrift believe that coffee can be a great fertilizer for plants because it contains some of the essential nutrients they need.
📹 How to use Coffee Grounds as a FREE Fertilizer for your Plants
In this video I show how you can collect and use free used coffee grounds as a fertilizer for your garden plants. I have been using …
📹 Benefits and Dangers of COFFEE GROUNDS and WOOD ASH in the Garden // Beginning Gardening
If you are just beginning gardening, you might not know that coffee grounds and wood ash are two really beneficial additions to …
Funny coffee grounds story. I decided I could throw the coffee grounds over the deck, and eventually go collect it. And I got up, brewed, and drank my coffee at the same time everyday. I started noticing a mouse near the coffee grounds, no problem, I just ignored him. One day I slept in. He was outside waiting, and was yelling at me. i had a coffee addicted mouse.
garden and coffee ground story.. I used to have an open compost pile where I would put food scraps including coffee filters full of coffee grounds. One day when I went to dump more I noticed that some critter had cleaned out ALL the grounds leaving only the paper filter. I kept an eye on the pile and witnessed the local flock of crows taking turns cleaning out every spec of grounds. I then dubbed the pile “The Crow Cafe”. One day when returning from town I got out of the car and was accosted by a barrage of screaming crows gathered around the Crow Cafe. I then realized I had not taken out the compost for 3 days and I was being informed that I was slacking on my duties.. After further thought I decided to enclose the compost pile so local wildlife could not get to the pile.. for their health reasons and because the last thing the neighborhood needed was a flock of caffeine addicted crows.
We struggled with blueberries on my property for many years, my husband simply gave up on them. Then, I discovered a nice trick. In the fall, I mulched the blueberry beds with a thick layer of green pine needles. Then, in the springtime when the buds are starting to fatten up, I “wake up” the blueberries by watering them with water steeped in one cup of fresh coffee grounds. The coffee brings the ph right to the perfect level. They’ve never looked better!
My Dad had a wonderful vegetable garden when I was a kid. The first year we lived there he rented a rototiller and taught us how to turn a 1/4 acre of our property into a garden breaking up the old sod that used to be part of the meadow out back. The soil was rich, nearly black and we discovered it went down about five feet before we hit a three foot layer of orange clay followed by all sand under that. We learned this when he dug the well. Fortunately he only had to dig down about nine feet before we hit water. Then my Dad went insane and started doing things that were absolutely crazy. Now we had moved in September so it was too late to plant that year. Everything we were doing was to prepare for the first year. When the town advertised that they were accepting bids to clean up the old bonfire pit behind the high school my dad underbid everyone and basically only bid enough to rent the truck. My brother, Dad and I spent every weekend until October shoveling ash into that truck. Then we’d drive home and dump it all into the garden and do it again. Before the first snow we hit another part of the property and my brother and I had to rake away about 1/4 acre of pine needles to expose what was under the needles. He called it pine “humus” but I’m not sure if that’s the correct term. We must have made hundreds of trips with the wheel barrow dumping all that into the garden. Next my dad found out about a poultry farm that supplied most of the eggs to the town as well as powdered eggs to the military.
My grandparents were off the boat Germans & had 2 acres that they planted mostly gardens. Maybe half an acre of grass. My grandmother had me taking stuff out to the compost bin when I was 6. I remember her sprinkling fresh ground coffee around the azaleas by her front door. I had forgotten so much that this article reminded me of. Thank you. They were happy memories.
Thanks for noting the science behind using the coffee grounds. I have been using coffee grounds for years. Infact, I went to a couple of coffee shops / deli and asked for them to save the pickle buckets for me and if they could just dump the daily coffee grounds in the buckets and set them out back. I would come by every other day or so and pick them up. In exchange, I would donate produce from my garden to those who need it. I did this through my neighbors and taking produce to Church. I ended up with applying several 5 gallon buckets to my gardens over the fall and winter. I mixed it in with some wood chips, Manure, Sea90 minerals and a few other nutrients. Then sprinkled some over the top as well. If you like the smell of coffee, every time it rains, you will have a beautiful smell of coffee in the garden.
I make many layers in my compost: hay from Craig’s list for free…cold, old manure, not fresh… forest soil because of the microorganisms… sand for the worms…coffee grounds from the coffee shop… worms from an old pile… weeds,early summer weeds if you want to keep out the seeds… mulched leaves…algae scrapped off the surface of my pond… greens the local grocery store throws out. Keep it damp. You don’t have to turn it. Add lots of greens just before winter and in any pile that the worms have depleted of them. Put layers of plastic and hay on top in the winter. I put three layers where I live because it gets down to 15 below zero. Use the piles you started first last Summer and you’ll have great potting soil and compost.
I occasionally mix coffee grounds, egg shells and banana skins, whittled down in my blender, mixed with a little water to feed my indoor plants with. Its not something I do regularly, just every now and again and they seem to appreciate it. I have very healthy house plants lol. I never thought to do it in my garden but now I know. Thanks for sharing.
After planting a number of new pines in my backyard, I heard pines love coffee grounds. I started collected the grounds for a couple days at a time and then threw them on top of the soil under these new plantings. After just a couple years, the pines went from about 5 ft to 25 ft. I was amazed. I stopped after two or three years and started putting them, along with other vegetable scraps, into vermiculture compost bins. Those bins turned into a 5 ft diameter leaf, grass, and kitchen scrap pile. This large compost pile has now survived a couple cold winters. It creates enough heat to stay above 50 degrees which is fine for the worms. The only problem is the decomposition heat during the summer. When it gets to hot, I try breaking it up to slow down the chemistry. Several times, the temps have gotten as high as 140 degrees. I figured my worms were all dead. But, no, some seem to migrate to a bit cool spot where they survive. The final compost is fabulous.
Another great article! For 4 years I had an extreme ant infestation inside my greenhouse. I decided to put a layer of coffee grounds from my coffee machine onto the surface of the soil as a mulch to see what would happen as I had 5 gallons of coffee grounds saved. To my surprise after one month there was only the odd ant that I found in my greenhouse. I did not mix the coffee grounds into the soil at all and cleared them from each planting hole when transplanting my vegetable starts. After 6 months I have only found about 4 ants in the greenhouse and for the first time in 5 years I have a bumper crop of tomatoes, cucumbers, peppers and my basil, chives, Italian parsley, Greek oregano, Rosemary and thyme are massive plants. Just thought that I would share my experience with you. Thanks again for the information.
Hi Brian I didn’t watch you 3 years ago, so don’t know if you will get this now. I don’t know how all this works. Thanks again, for the info on coffee grounds. I was saving back and putting in garden last year, so I think it is time for my husband to build a compost bin. I’ve always wanted one. Of course the chickens usually come first. Ha You know, its really nice of you to let people know a cheaper way, when possible. Thank you for that . We appreciate you
I used to throw out my coffee grounds out in the dirt of my hydrangeas and for some reason it helped with the changing of the colors of the flowers. I must say they where stunningly beautiful. So now I always do that. I did it like once maybe twice per week. Just threw them out with a bit of extra water and that’s it. Worked great for me on them that’s for sure. Much luck to everyone ✌
Houston: collected bags of coffee grounds from the HEB supermarket. spread on the soil during the fall for two weeks then turned it under. Rotate the soil, several times before planting at beginning of March. Explosive improvement in growth, greenness and output which I attribute to the trace minerals as many coffees are grown in rich, mountain or volcanic soils. cherry tomatoes, squash, basil, cilantro.
i’ve been using 1000 to 2000 pounds of coffee grounds from our local coffee shop on my large garden for several years and have encountered no problem, even though my soil is excessively acidic to start with…i also mulch heavily with maple leaves that i save over the winter & my yields far exceed those of conventional gardeners…
Many years ago I lived in Tennessee and decided I was going to plant a dogwood tree in my yard. I dug a hole 4 in deeper than necessary, mixed used coffee grounds with rich soil to put in the bottom of the hole. I covered that with 2 in of soil and then made a mound to set my baby tree on. I think covered the rest of the root of the tree and watered well. With minimum maintenance I grew the most outstanding dogwood tree with the most brilliant pink flowers. It grew fast, tall and wide. All of those neighbors who told me that I could not grow a dogwood tree in that area of Tennessee were forever humbled because I told them I could and I did
My very large gardenia bush loves the coffee grounds I put on it about twice a month. Gardenias have a short bloom but when mine blooms in late April each year, it explodes into the overwhelmingly captivating scent of over 100 blossoms for about a week. Heaven to sleep immersed in that fragrance when the breeze blows it through my nearby bedroom sliding door. I just sprinkle the grounds on top of the ground under the bush and it has never shown any signs of distress from it, only vibrant growth and blooms. I never dig it into the soil. So “if it ain’t broke, don’t fix it” is my philosophy on the gardenia. I’m unsure how much the bougainvillea’s like them though, so I limit them to just one sprinkle of grounds per month. Our HOA forbids compost piles so I can’t use that method unfortunately.
I have been using both in my compost for ages. I put compost tea under my new transplants and it seems to help them not go into shock too badly. Have not had any coffee grounds for over a year, seeing way more pests but also added some new plants. Brassicas don’t do well here. Great info, thanks. I did not know blueberries love coffee grounds. Our dogs would also try to eat my gardens soil. They gave it up, when I took them off kibble. They eat whole foods now. No more eating the soil.
When I was a teenager, my father used to save up the coffee grounds and sprinkle them under our azaleas. I don’t know what was going on chemically, but the azaleas absolutely loved it. The bloom production increased and the rate of growth increased as well. We had the most beautiful azaleas on the block, and it was mainly because of the regular depositing of coffee grounds beneath them.
I just found your website and really enjoyed my first article! I used to visit Starbucks regularly to pick up the grounds without even buying anything. I live near Seattle and we all heard that we should scatter coffee grounds around our rhodies and azaleas, even though the soil here is universally acid already. I never noticed that it made any difference to my plants, so I stopped doing it. You and your son remind me of my dad and me doing scientific experiments; he was a geologist and I became a medical microbiologist, a field which clothed, housed, and fed me for forty years! My mom encouraged my naturalist side by providing habitats for various caterpillar cocoon and chrysalis propagation, resulting in a lifelong interest in entomology (couldn’t make a living in it, though). Keep up the tutoring of your son, especially outdoors.
red cabbage is also a great pH indicator. Red cabbage contains a water-soluble pigment called anthocyanin that changes color when it is mixed with an acid or a base. The pigment turns red in acidic environments with a pH less than 7 and the pigment turns bluish-green in alkaline (basic), environments with a pH greater than 7.
I use coffee grounds in my compost and it’s been super beneficial to my plants in that form. It breaks down pretty quickly which is nice too. I use the bokashi method for all my kitchen scraps. I made my own bucket with a spigot and use the liquid (200:1 dilution) as a liquid fertilizer as well. The plants love it too!
We added worm towers to our raised garden beds and periodically put our used coffee grounds directly in the top of the towers. The worms love it and as a result of their increased sized and activity throughout the gardens, our produce has been delicious and prolific. Love the website! Thanks for so.much great information!
10 Years ago I moved into a townhouse in Virginia. The backyard soil was hard as rock and actually filled with lots of granitite debris as a result of fill dirt when built. I removed the rocks to a large extent and found lots of clay and a higher than I wanted acid Ph. I spaded the yard (roughly 20’X20′) and covered it with 4 inches of coffee grounds from Starbucks. I did this primarily because I know the few earth worms I found would thrive in it and I needed cheap organic matter to mix with the clay. Later I was told that I increased the acidity because of this, but you have explained I really did not. Since then, I have reduced the size of the planting area to just three small beds due to having such a small amount of sunlight here (tall house and trees block the sun). However, I have amended the soil each year with my own compost and it is easy to turn over now. My potatoes and asparagus love it.
I use coffee grounds and wood ash as a light mulch around my dormant/ over wintering crops during the cold months (garlic, strawberries, dormant trees). I make sure to stir into the mulch every one in a while so it doesn’t cake up and repel water- as he says in the article. I have found this to really help the crops when they wake up in the spring/summer. My garlic bulbs are noticeably bigger since I started doing this, though I also give them some nitrogen in the late winter/early spring. During the growing season, I add coffee grounds to my compost, like he recommends. Great post and discussion!
I’ve been just composting my moms “pods” coffee grounds (once I empty the pods contents) in my Compost Tumbler. And, with it all is scraps from veggies and fruit. Some leaves from fall and even some “bunny poo tea”. I am not sure about adding any wood ash. It can be too alkaline for me to use without worrying about too high a PH in any soil I would add it too. Most plants that you would want to grow like an acid to neutral PH. I DO wonder IF the caffiene in the coffee grounds WOULD affect earth worms? I know that using “tobbacco” to the soil WILL possibly kill the earthworms, the nicotine. Now, I KNOW, many people will be thinking, “who would add tobbacco to soil?” My answer is that I had wondered about IF I could use my husbands snuff “left overs” since it is “organic matter”. I know I should have figured out that all the leftovers from “snuff”, would be a form of straight out “poison”, from the nicotine. But, after I figured THAT out, I kinda wondered IF “Caffiene” could harm worms which we all NEED and WANT in our soils? Anyway, I do compost my moms “Kuerig pod” coffee grounds and it is just a small bit of my compost additions. Although soil SULFER CAN help your soil PH to get more acidic, It tales a LONG time before it will do the job, so, avoid wood ash in high Ph soil. OR if you want to grow blueberries. Sorry IF I repeated anything that the article maker already said. BTW, THIS easy soil PH check SHOULD be made into it’s own article by “Next level gardening”. Sorry if I seem pushy, BUT, it is just a really neat way to quickly and easily check your PH, and most people wouldn’t see it since it is at the end of this article about using wood ash and coffee grounds in your soil.
Would you recommend putting the coffee grounds and wood ash in my big trash can (the kind we roll out to the curb every week) compost and mixing it in with that? I have had HUGE success this way ensuring worms and bugs get in through the bottom of it as well as air holes for oxygen to get in breaking down kitchen scraps as well as the coffee grounds & wood ash. Take a wheel barrel full once it’s all good and broken down, go around to all plants and trees spreading the compost which has all the positives mentioned and NONE, that I can tell by the article as well as 10 years experience with this method of composting, NONE of the negative’s mentioned. Great article, super informative as it totally relates to how I garden 👍
Here in the desert southwest in the USA (I live in Las Vegas) we have very heavy, rocky clay soils. You don’t generally want to plant in that stuff, but rather build up a good layer of rich topsoil. However, the heavy clay soils underneath can still play a part. When you are preparing your beds, mix in all sorts of yard waste and coffee grounds. The coffee grounds help with the high alkalinity of our soils here, but more importantly, allow for much better water drainage and keep the soil from packing quite so hard. Since you’re packing lots of good topsoil above it, the heavy clay underneath isn’t nearly as important, and things that might be a problem elsewhere, actually work well here. So dump in the coffee grounds and grass clippings by the pound and bury it down deep. It won’t be a huge nutrient boost, but it will keep your topsoil healthier.
My compost was amazing with lots of coffee grounds from a cafe after about 8 months . But, when I used it as a mulch, not so good . And when I sprinkled it on my geraniums in pots, all their leaves died immediately !! I quick cleaned all the grounds off the top layer of the pots and then flushed water through the pots as best I could, almost drowned the plants but they lived and got new leaves pretty quickly .
I actually got in trouble with my landlord a little, using coffee grounds as an amendment. I was just using my grounds from my morning filter press coffee, pouring it around the base of some fruit trees we had in the back yard. The rental contract had the landlord taking care of the trees, and he came to me a couple months later, asking what the hell happened to the trees, as they were fruiting so prodigously, some of the branches were close to breaking. When I told him what I had been doing, he was just like, “please stop”.
Great test! Love it! However, in my experience, the best water to test with would be reverse osmosis. It is closest to neutral. Many of the bottled waters are on the alkaline side. I use a test kit on my water regularly and so far it was the only one that was true neutral ph. I am sure close is good enough though. Thanks for the article.
I’m so glad I found your website. I’m gearing up to do a fairly large garden this year, and I’m trying to learn as much as possible. I also appreciate your great article production! Something for you: I noticed at about 6:05 there’s a bit of audio interference. I’ve found that I also get that interference sometimes when my cell phone is too close to my equipment. I’m not sure what you’re using to capture audio and article, but if you can move your phone away from it (or putting it on airplane mode might solve it as well) that might help prevent that. Just in case you’re wondering what that might be from. Cheers mate!
Good article. Regarding coffee grounds. It also helps prevent the soil from becoming hydrophobic, which is a problem with using bagged soil in hot climates. Of course, this requires mixing it in with the soil. To mitigiate the issue nitrogen tie-up from the soil, mix the grounds into the soil the prior to the growing season, allowing enough time for breakdown. And don’t exceed an 80% (soil) to 20% (grounds) mix. Also, I’ve found that coffee grounds repel/kill grubs. I placed a layer of coffee ground on the surface of a 20 gallon fabric pot. The next day I found six grubs dead on the surface. Apparently even on the surface the grounds managed to release a grub repellent down into the soil forcing the grubs to seek escape, howbeit an unsuccesful attempt. So, in addition to repelling slugs and other vegetable damaging pests, it seems to work on grubs as well from the top down.
I was raised in KY. My dad had a compost in our back yard when we moved to town. He swore by chicken poop and chipped tobacco stalks. He mixed them in a 55 gal drum. Every time it rained I had to run outside and take the lid off of the drum. He would use the water on top of our compost heap. If you have access give it a try.
Just wanted to say thanks for warning about the wood ash. We live in Idaho and have a woodstove that is our heat in the winter, so we have a LOT of wood ash. I googled uses for wood ash and saw that you could use it on your garden, so two years ago (when this article was being made, actually) I made sure to liberally sprinkle every plant with wood ash when planting it. Our garden died. Like, D.E.A.D. I don’t think we got a darn thing out of it. Discouraged, I didn’t plant a garden this past year. And then during late winter of this year (January 2022), I stumbled across the fact that wood ash will make your soil more alkaline. Now, I’ve never had my soil tested but I knew immediately what the problem was with my failed 2020 garden. Quick – think of a plant that’s associated with Idaho. Potatoes, right? Guess what kind of soil potatoes love? Alkaline. Our soil is already alkaline. Adding wood ash to it just sent it off the charts. 🤦🏻♀️ No wonder nothing grew. Now we sprinkle the wood ash into the compost bin when we add in new ingredients. Much better use for them in high alkaline Idaho. So I appreciate articles like this where you explain that wood ash isn’t just for every type of soil. If I’d known that, I probably would’ve had a thriving garden in 2020 and 2021. 2022 it is! Better late than never, right? 😄 Keep up the good work!
Coffee grounds make the worms do the wild thing at night, and you should see how much reproduction goes on. I would not use it nightly, more like once a month, but keeping it moist is a must. I got more worms this way than when I started out. I can honestly say, makes my worms love staying in their bin when I do add them.
I worked on a worm farm for 5 years. This was to ‘grow the worms’, then we graded, sorted them into Compost Starter Boxes or support boxes. We had a local Cafe that would keep the spent coffee grounds and we would add them to the worm beds. The beds were watered very well. Also we would add Lime and other “secret” ingredients. Coffee grounds helped the worms a lot. I don’t know if the worms aquired an addiction to caffeine, but I doubt they did as they did not try to crawl out of the boxes in the cool area, unlike some brought crazy worms we had to buy as business was booooooming. Coffee grounds are a great usually free addition for worms, but remember to keep them in shade and wet a piece of carpet or something on top of the compost your worms live in. if it rains they will come to the top to avoid drowning and if its hot, they will need added moisture/ coolness
I have worked in a food plant for 37 years & we grind coffee & I have used Used coffee grounds & fresh ground waste coffee, coffee chaff & whole roasted coffee beans, as well as green beans. Green beans mold after they are wet. Most people Shoot the bull about coffee & do not know what they are talking about. I did not untill I used CG by the tons on 1 acre garden. I am glad you know what you are talking about, most do not, thank you for working out the truth instead of just making a article. We need more gardener like you. I found coffee compost made from coffee chaff, works good with garlic, if it is worked in the soil a month before planting the fall cloves.
I do know that beans don’t like coffee grounds as a top dressing, because most raised beds also have peat moss, which also adds acidity. The reason is that beans are a nitrogen fixer but don’t do well with too much nitrogen…which means you will want to add hydrogenated garden lime according to your package directions. My beans love it and I definitely don’t add acidic items of any kinds and am transitioning to coir. Until then the peat in my raised beds is counteracted by the lime, hopefully. Beans are doing swell. Thank you for the excellent adviced on composting. I had been afraid that my grounds would just go to waste in the pile in comparison to top-dressing around plants. HOWEVER: apparently slugs HATE coffee grounds. Thank you for not just doing the typical youtube vids that are all blabber and no real info.
Hi: I Live in Alaska and have very acidic soil because we have lots of spruce trees. My question is about wood ash, more specifically about wood ash from a wood pellet stove. This ash is fine, but it is more black or dark gray, not white, I used wood ash in Oregon, as there I had wood burning stoves. But here, I use a wood pellet stove, as I am getting older, and let’s face it, burning wood is messy. SO, is it safe to use the ash from my pellet stove in my garden beds? Thank You so much!
We decided in spring to get an elephant ear plant, having never grown one (and I wasn’t sure if living in a northern mid Atlantic state would kill it). We started dumbing a spaghetti jar each week of used coffee grounds and I have to tell you it grew over 7 1/2 feet tall! Everyone in the neighborhood was shocked to see how big it got by fall (and it actually stayed green until the end of November!!!). I’m not sure if it was because of the grounds or not, but I know that particular front garden had a HUGE spread of all of the miniature rose plants we have in the same area (they sprouted to 2 ft + in height AND 3 ft wide 😳😳).
I use egg shells also, however, since it does tend to take a long time for the shells to breakdown in the compost and since the calcium is not readily available when added directly what I do is add them to my wood fire. When I add the ash to my compost I am assured that the compost will get the benefits of the calcium immediately.
Love how you do your pH test, that is so cool, if you have no other methods. Much prefer the more accurate solution myself. Tomatoes like a more acidic soil, so using pine straw mulch is a sure winner. Last year, I had a very neutral pH, around 7.5 and tomatoes were struggling but added some gypsum, a few pinches of sulfur and potassium nitrate and that made a significant difference. Planted in early August, still got a bountiful harvest in zone 4; imagine that. Funny how all the ingredients in black powder are actually used, in some capacity, as fertilizers.
I use coffee grounds in very large quantities, 10-15 gallons at a time, in my garden. It has many beneficial effects. I have very alkaline soil. I use coffee grounds to increase the acid in the soil. I mix them into the soil. I add nitrogen in the way of ammonium sulfate to provide the extra nitrogen that the coffee grounds consume as the decompose, and to add acid. The sulfate in the ammonium sulfate increases the acidity by combining with water to create a weak sulfuric acid solution. As the coffee bits mix with water and decompose, the carbon decays back into Carbon Dioxide. Some of the carbon diaoxide combines with water and forms a weak acid, which I believe is called carbonic acid. Other benefits of coffee ground in the soil include a substantial improvement in the friability of the soil and an increased ability to hold and release water to plants. If you apply a thick layer of coffee to the soil it will repel water for a season, but then it all breaks down and the water gets through. For this reason I prefer to actually mix the coffee grounds into the soil to a depth of about 6-8 inches. I also use biochar, formerly known as charcoal, in my garden, along with wood ashes. Yes, you have to beware of its increased alkalinity, but I am frequently amending the soil to increase the acidity anyway, so why throw away all that potassium? I use a combination of ammonium sulfate, leaf mold, coffee grounds, compost, and elemental sulfur to increase the acidity in my garden soil. I really liked your soil pH test to get a rough idea as to the soil pH.
I throw coffee ground and fresh coffee and vegetables fertilizer, not all at the same time. It does wonders! My plants especially Basil super green and shinny leaves. Now I have way too much Sweet Basil. My Thai Basil AKA Red Basil is is thriving also. I watched tons of gardening articles and everybody is just doing what they think it’s best for their plants. Is what I noticed. It’s very hard to try and follow one article and others is doing totally doing opposite lol. So I just use and care for my plants what I think will work for me. Your articles are great as well.
I sprinkle coffee grounds on top of beds in my front yard to deter the community cats from digging in there. When I lived at a house where there were hydrangeas in the yard, I sprinkled my coffee grounds under the hydrangeas to encourage blue color. The pink hydrangeas gradually turned purple and finally blue. I’m glad to know not to dig them in.
I would like to connect your discussion of coffee grounds with the wood ash that has biochar in it: make biochar out of coffee grounds! It solves most of the problems you mentioned and turns the carbon into a permanently stable structure that will amend your soil basically permanently. I use an old Dutch oven, fill it with any mix of coffee grounds, nut shells, wood chips and any other organic material, as long as it is very dried out. I get a roaring fire going in our woodstove and then prop the oven with the lid on, on top of an old metal grate. After 20 minutes, the gases are coming out of the pot and igniting. The heat generated is not wasted, it heats our home. And half the carbon remains in the material instead of going up the chimney, and can be wetted, innoculated and used to improve the soil, especially when planting trees and bushes. Gives them more resilience to drought. See Youtube website Edible Acres for a demo of doing this.
My berry bushes, (red and black raspberry and currant) LOVE coffee grounds. I had a transplanted red currant that had died back to only two sad stems with a few leaves. I added coffee grounds around the plant in mid-summer. After that, it put up new stems, leaves and actually produced a few currants. Years later, it is my largest and most productive red currant bush. My raspberries grow hugely large canes and produce in profusion.
My father burns every year in the tomato patch after we harvest. In that spot tomatoes grow bigger, more bountiful and have more volunteers. I will say the soil was also manure compost originally from years ago. The comparison was between a compost and burn bed vs a clay dirt natural bed. That clay beds gone now and a garage built over it but it did grow green beans very well.
I once used coffee grounds on a zonal geranium, and it was a fantastic plant, largest and most flowers I ever had. Had some people working on house. And they burnt two small piles if tree clippings and small branches. Ended up with two heavily ashed circular patches, they told me grass would not come back and could not grow anything there. Well, I took a hoe and hoed up area mixing ash into soil. Then I bought marigolds and marigold seeds. Outlined circles with plants so guy who mowed lawn would know not to mow there, and heavily seeds the centers w the marigold seeds. They grew very well, and I got compliments from neighbors. And grew so thick and close together that I had very few weeds.
Ive had explosive results from coffee grounds and growing plants before. I also grow cannabis, and my only main concern would be dropping the acidity to low if I have to much in the soil/ and or compost I make. Im making a compost for my cannabis grow next year, since this ones in full swing already. I am just getting a head start on next year, and Im adding a lot of coffee grounds to my compost. I added some atomite(mineral mixture), so hopefully that will adjust acidity levels. If not I have some dolomite lime I can add to buffer the PH. EDIT: Ok, nevermind. Dude said its not acidic anymore if its post brewed coffee.
Quite a long time ago, I added the ashes from my fire to my compost bin, not realising it was still alight in the middle. Long story short, I ended up with a melted heap of plastic and my garden bed around it on fire. Very good lesson learned, always make sure your fire is really out. I guess if I had watered it straight away, it would have been fine 🥴
Great article and pH test! I have both a Starbucks and wood BBQ place within a block, hence unlimited coffee grounds and wood ash. Its Fall and leaves are falling. My question is what approximate ratio of the 3 should I be adding to my mostly empty large compost bin? Guess I better perform my own pH test as well! Apparently, slightly basic.
In my experience, wood ash and coffee grounds in the garden are fine. To be safe, add them to the compost, mix and age as normal, and you’re golden. I wouldn’t risk adding straight wood ash right to a container or around the plants. I doubt most people have enough coffee grounds at any given time to cause harm if they’re just dumped around. What I used to do growing up in a house with a wood-burning stove was have a nice hot fire with proper firewood (no treated wood and no Duraflame logs or those logs or pine cones that make different colored flames) in the evening and close up the air intake vents when I went to bed. The fire would burn out overnight and usually leave nice big chunks of wood charcoal. If I’d left the vents open, the wood would’ve just burnt down to ash. Read up on biochar and this seemed like an easier, if not by-the-book way, to have biochar be a nice, free, no-effort by-product. I’d sift the cold ashes on a metal screen outside, set them aside, take the charcoal out, then break it up, and put it into a bucket of “compost tea,” let it sit a few days and add the charcoal either straight to the garden or into the compost pile. DO NOT USE BARBECUE BRIQUETTES in your compost or garden.
One thing I have run into when collecting used coffee grounds from shops such as Starbucks is that they can get moldy fairly quickly. So consider spreading the grounds on some newspaper sheets in the sunlight to enable the grounds to dry out. If you have a little used patio or area of your driveway, consider using that space because the bottom heat will speed up the drying process. Watch the weather reports so you know it won’t be raining while the grounds are drying.
I use to get coffee grounds at my local coffee shop. I brought new (unused) paint cans and they’d dump grounds in those. To thank them, I brought fresh cut flowers to them. The other customers loved it. But then came Covid and when they reopened, my brand new cans a three of my vases were gone. My motivation was to feed the worms. I still scatter used grounds into my lawn.
Thanks for the excellent article so many articles for and against coffee grounds in the garden and in compost I’ve only lately being saving my coffee pod had been saving them before but because of all the negative reviews I tossed a whole bag of them I’ve since started a Dave’s fetid swamp water barrel so I’ll add it to my barrel anyway Thanks for the excellent article love to see kids of all ages helping out it gets them involved with nature
The numbers for coffee grounds aren’t that hot, but the worms, according to my Uncle Mickey, stay up all the time, from the caffeine – a worm’s live is not that hot – so, what do they have to do? Yep. They reproduce like mad; and the little worms all make worm castings. Thus, good things. I trust my Uncle!
If your dog is eating dirt that means your dog needs minerals because the food that we feed our pets is nutritional deficient in the best thing to do is feed your dog raw meat and organ meat because in the organ is where a lot of minerals are for dogs and cats. If you notice in the wild When Animals take down an animal they eat the guts first because that’s where all the minerals are. Hope that information helps to figure out why your dog eats dirt
The active nitrogen from the used coffee grounds AND the carbonic acid result from the ash… Make them both great compost materials. As you said – the coffee grounds are treated as-if “greens,” the ash is treated as-if “browns” But mixing them together helps in the breakdown of the used coffee grounds Putting 4 or 5 whole coffee beans around the blueberries is nice, but don’t pack more than maybe 10
I once bought some dirt from Home Depot to put in some pots and I used to use those to grow flowers mostly. However I once used two of those pots to try to grow mangos. Both plants germinated and started to grow, however, they stop growing by the time they reached about 30 cm (one foot). So, i just happen to brew coffe daily, so I started to pour the brewed coffee grounds to those pots and to my surprise both plants grew like crazy, one of them is almost man size by now. I think that besides of the nutrients it has to do with humidity retention, those varieties of mangos grow in semi-tropical areas and I live in Mexico city so it is much dryier and colder, but enough sunlight and those coffee grounds seem to have done the trick.
Laguna Beach California: I used to manage a busy coffee shop. I rode a bike to and from due to parking issues. Late night ride home saw me with 20 pounds or so of bagged used coffee grounds across my handlebars. My organic garden and compost heap awaiting. One night I was surprised stopped by 2 Police squad car’s. Full beam search lights with a microphone yelling freeze. Then asked by microphone what do you have in the bag. “About 20 pounds of Columbian’ I replied. Back in the day long haired guys were often stopped for drug searches. I was let go and everyone laughed. Just a funny memory. 🏖️🚴☕👜🚔😍🌽🥕🌻🌷👍
I have a recycle bin (about the size of a 3 lb coffee can) next to my espresso machine, where I crumble egg shells and used grounds. When it’s full I simply break up the mix and sprinkle across the small front yard. I’m not sure if it’s the grounds and extra calcium, but the yard is looking healthier.
Every day, I just walk outside with my used coffee grounds in my portafilter, and shake them in a new area of my yard. We have hard clay soil that absolutely sucks. I compost and steal all the neighbor’s leaves and buy worms (I like to think I am rescuing fishing bait worms and setting them free) I hope in a few years of dumping all this stuff around my yard, the clay soil will start to look like something a plant will grow in.
seen as he mentioned where the word potassium comes from I thought I’d share a nugget, so yes potas-sium is simple the latinised version of potas-h purely for the period table, this is because the scientist who first isolated potassium as an element did so extracting in from. . . potash on a separate note, and this happened independently at a different time, potassium is alkaline, alkali is derived from the old arabic word al’qali which means . . . burnt wood and cheers on the tip for chucking the grinds straight in the heap to help it kickstart I get all kinds of free waste products from my local village pub 2 of which are the ash from their big open wood fires and all their coffee grinds, I was just adding the grinds to the soil but actually speeding up my whole composting process would be really good
Oh dear, I’ve been going to all the trouble of spreading out my daily used coffee grounds so that they dry out and don’t mold, which takes a couple of days, then adding them to a container, to add to soil to increase acidity. I just heard you say don’t do that, use it in a compost pile instead. Wet or dry(which would be a waste of unused expensive coffee grounds)? I was wanting to use coffee to change acidity to save money from buying products I’m trying to make my own soil and reduce buying gardening ‘products’. Eagerly awaiting your answer. Thank you. A Newby.
Hi nice to see some new technique to grow tomatoes. I am going to try them this year to start seedlings. Thank you. My Main problem is slugs in my garden. I keep killing them with yeast water I am try to control them but I see them come back every year. Please advice. Thank you. Have a good year. Happy gardening 👨🌾
I grew morel mushrooms from just honey, a compost pile and wood ash. They only flushed once though. Ash is an awesome amenity. Coffee grounds are a bit tricky because you can overuse them super easily. Great for my Roses in small doses. Eggshells are also tricky I shocked my plants once before flowering thinking they needed cal/mag.
Hola again! I live in Andalucia, Souther Spain where I have 5,000m mainly olive groves and fruit trees. IFor 15 yards I just piled up branches from shrubs etc until it ventually composted down. Last year I eventually developed that area and spread out all the composted material. Naively I Ithought I could just plant into it. Nothing survived and I then learned the chemical imbalance was resulting in too much amonia which was killing the roots? What should I do to ensure that I can plant trees and shrubs there please? P.S. Only discovered your site this morning; love the content but particularly your presentation skills. Thank you,…I’ve both liked and subscribed!
WOW Great article.. I heard coffee grounds were good for tomato plants.. Also, we have 2 very big pine trees dropping needles in our back yard. Is the acid from the needles leaching into the soil? What should we do with the needles? Get rid of them, burn them, or add something to them??? Did you do any articles explaining best kitchen waste to compost? Where do potato skins and egg shells and fish heads fit in the compost spectrum?
Many years ago my parents purchased 10 acres for their retirement. It had a older home which had a big wood stove. Mom loved it; used it a lot. There were also big apple trees. Great for juice but worms and some kind of disease, maybe apple rust made the apples not very desirable to eat. She started taking all the ash from the wood stove and spreading it on the ground under the apple trees. We had great apples after that! Really worked. Most of the wood we burndt came free. It was maple, cut offs from a pallet factory.
I have experimented a lot especially on tomatoes. There are tricks to get more flavor. I have wood heat so I mix ashes into compost and manure. One thing not mentioned i do is make a tea with coffee grounds in a 5 gallon bucket. Also manure tea is excellent. Also I have seaweed available to use as a mulch and I think it adds minerals, but be mindful of the salt. You can pretty much tell if an experiment is a success or failure by the results.
I use Coffee Grounds with ground up Egg Shells (for the additional Calcium). Only downside, that I’ve seen is that it’s only good for like two weeks, then I have to fertilize again. I have a friend with with a small restaurant and Coffee Shop about a block away. I get it free. All I get from him is “fresh grounds”.
Wow! This is a very old article that popped up. But great timing as I just got a delivery of used coffee grounds and some chaff. It’s Autumn (Fall) here so I’ve gathered heaps of leaves and I’m going to mix those in with the coffee waste to make some great compost. I’ll add paper too and any other garden and kitchen waste we have. I’m expecting to make a good cubic metre/yard of finished compost.
Great article. I am kind of a “Composting for Dummies” kind of girl. I grew up in Texas perusal my grandmother compost in a bin around her fig tree. Coffee grounds were a staple in her compost pile. I am a Native Texan REALTOR who loves to garden organically. I garden at home, my yard is a Certified Wildlife Habitat. I also am preparing an acreage property to build a home using what I call “slow clearing”. I have what is probably the largest compost pile you have seen because of my slow clearing. I am removing a lot of cactus and some cedar (Ashe Juniper) and compost a lot of it. The larger branches I use for fencing, building things but the smaller twigs go in the compost. In the Texas Hill Country, soil for the most part has high alkalinity. Black Walnut is native here but I do not have any on my property.
I use the ash from my fireplace insert on my driveway and on my path to the barn to keep mud off my shoes, it changes the types of weeds that grow in those areas. Butter dock likes it and buttercup doesn’t. I will have to use the remaining coffee grounds of my deceased husband’s stash on my hydrangeas and see how that helps. I had some blue blossoms and some pink blossoms on my originally blue hydrangea last time with “spent” coffee grounds. 🙂
OK, the soil in the raised beds is around 8.5. last summer everything struggled to sprout and produce. The sunflowers did grow to about 12′ and put on heads but the seeds were empty. The tomatoes were slow to fruit out and most never ripened. The zucchini produce to some extent but the yellow crookneck barely even flowered. Most other seeds never sprouted or barely sprouted. Potatoes were small. The wildfires probably had something to do with it. How do I get the Ph back to neutral? I was told by the local nursery that wood stove ashes are worse for your garden than open campfire ashes. I’ve been dumping then in the narrow gap between the bed and fence hopefully to kill off weeds. The compost pile contains lawn clippings, rabbit and chicken manure, coffee grounds, and a few kitchen scraps that can’t be given to the animals. I thought I’d build up the low bed with it and dump the potato starts in it using scrap lumber slabs as the frame.
Living next to wetlands, slugs are a constant bane to the garden, whether ground level, raised bed, or container. Water that soaks coffee grounds, strained of solids and put in a spray bottle, deter slugs big time. Even in containers, I can see their slime trails working their way up the sides, coming to the line of dried coffee water, and after following the coffee line looking for a way up into the container, they make a U-Turn back down onto the ground again. Coffee grounds around an ant or termite hole … they will make another entrance rather than even try to move coffee grounds from their door. Dried coffee grounds has been a great carpenter ant hill treatment at the foundation of the cabin. I use a French press, so the grounds are almost powder, which makes a pancake dust over their hills. It seems to do quite well in that form. To collect and decant grounds, I use a resale Tupperware orange juice container with spout, and dump my French press grounds in it. Every few days I use the narrow pour spout to slowly decant coffee water through an ultra fine mesh black zipper bag (usually for laundry) and the water transferred into a spray bottle for slugs, and the solids suspended in the mesh bag in the sun to dry. The coffee spray goes on the ground and on containers around my plants to deter slugs. The dry grounds – now reduced to powder patty – is crushed and dumped on carpenter ant/termite hills around the foundation. The caveats are don’t spray on buds or flowers or leaves because it can also kill your pollinators.
So I’ve got three 4×4 bins full of compost. I’ve been taking the coffee grounds from the local gas station. I’ve probably got 150–200 lbs of grounds in the compost. It’s mixed with everything else you compost (grass, leaves, saw dust, food scraps etc). Should I not use it this year? It’s been sitting all winter. I’m also a drywaller so I’ve been busting up drywall scrap and adding that as well.
So I use my used coffee grounds on my Gardenias to increase the acidity in the soil. I COLD BREW, for the very reason that I dont like bitter coffee and it keeps the acids in the grounds. You can always warm up Cold Brew coffee if you want it hot. Thus you can use the grounds and still get the acid for the soil. (And get a better tasting cup of coffee.)
We burn about 2 cords a year and I save all the ash for the gardens and compost. However, it works best if spread only lightly. A sprinkling of woodash on the area where I last grew tomatoes and peppers really helps the next growing cycle. I do not grow tomatoes or peppers in the same place 2 years in a row. The woodash works wonders in the pollinator/native plants gardens.
For the past couple of months my community garden has been taking about 3.5 gallons of used coffee grounds per week from our local coffee shop (thanks Zeke’s on Washingtobn Ave, Baltimore) for our compost bins. Is there such a thing as too much coffee grounds in compost? We also add food scraps from about 10 households, lots of weeds, some spent grain from the brewery (thanks Suspended, also on Washington Ave., Baltimore) shredded paper and egg cartons, and some wood ash about twice (or more) times a year.
Just a question about the use of ash.I live in Riverside California which is decomposed granite mixed with clay and because we are quite arid the soil tends to be a little on the alcaline side. Out here we are growing mostly Cal natives most of which are fire followers which means their seeds need fire to break the dormancy coating and germinate.I am trying to grow a plant called Yerba Santa the protocol calls for digging a fair sized area down to 6 inch’s and disturb the area real well.Then Lightly moisten the soil and just press the seed in. Followed by a foot and half pile of straw or foxtail clippings,set the whole pile on fire and let it burn down.Next water well and wait for germination.My worry is this one time jolt of pot ash is to much considering the already high alkalinity.Evidently these plants thrive on charate especially from their own species.
Oh gosh! 🤦🏾♀️ i just ran out today and bought a bag of new unused coffee grounds and poured it in 4 of my planters, mixed it up in the compost. Only one currently has seeds which are bok choy and peppers, but plan on planting others in the other planters this month! please tell me i did not mess up?!? 🤦🏾♀️
I am growing tomatoes and peppers in buckets and bags. Should I add worms… I am subscribed and the bell is black, however, I am not getting notifications for some reason, yet when I go to your articles, there is one from 42 minutes ago… I get notifications from others, so will have wo watch for yours until I figure it out… I am using farm store bulk mulch and bagged soil in my raised beds, buckets, and bags. Do I still need to test for pH ? My original garden was acidic so I put lime on it, but I can’t get down to work a regular garden any more.