Can A Raised Garden Bed Be Installed On Concrete?

When gardening on concrete, raised beds are particularly helpful as they allow for the creation of a suitable growing environment. Concrete is not a good growing medium, so gardeners can add high-quality materials to create a suitable growing environment. With the right setup and care, raised garden beds can thrive on concrete just as well as soil. To create a successful do-it-yourself (DIY) concrete raised garden bed, follow these basic steps:

1. Choose materials that are comfortable for most gardeners and don’t require excessive bending. You may want to build the bed higher if you have mobility issues.

2. Place raised beds on paved surfaces, including concrete and asphalt, with some modifications to support drainage and healthy plant roots. Ideally, a raised bed on concrete should be 32 inches tall to give roots access to nutrients and room to grow.

3. Prepare the ground and raised garden bed to go over concreted and pavers. Raised beds built on dark pavement will usually have higher moisture needs than those built on a lawn or natural surface. Raised beds on concrete don’t get the benefit of cool soil, meaning they heat up and dry out faster than in-ground beds.

4. Be aware that concrete is alkaline, so over time, the pH of your garden soil will be less acidic than it would otherwise be. By following these tips, you can create a successful raised garden bed on concrete that suits your space and gardening needs perfectly.

Do raised beds need a base?

For raised beds with depths exceeding 50 cm, the incorporation of a layer of rubble or stones can facilitate enhanced drainage. Conversely, for beds with shallower depths, it is advisable to refrain from the addition of rubble to ensure optimal root growth.

What is the best surface for a raised bed?

Raised beds can be built on various surfaces, including soil, grass, paving, tarmac, concrete, and sloped gardens, without the need for foundations or cement. WoodBlocX raised beds are unique in their design, featuring a series of strong dowels that can withstand ground movement. To line the raised bed, use a geotextile membrane liner at the bottom for better drainage and a damp proof membrane on the sides and over the buttresses for excellent structure condition.

Soil for raised beds depends on the type of plants you plan to grow. Rich compost mixtures are effective but expensive. Topsoil mix and soil improver or compost mix are recommended, with sandy soil being the best all-rounder. Using bought-in topsoil allows for more control over weeds. Homemade compost or manure can be used to enrich soil, but check if these mixes are suitable for your needs. Plants and vegetables can be supported with solid and liquid fertilisers.

When not to use raised beds?

If your yard has naturally deep, level, and well-drained soil, you don’t need raised garden beds. Instead, you should place your beds at ground level and create pathways around them. The soil in your pathways will become compressed over time, and your soft garden beds will remain slightly raised. Raised beds have several disadvantages, including higher heat and drying times, high costs for creating frames and soil, difficulty in using green manures or cover crops, and more work to change the layout compared to ground-level gardens.

Gardeners often find that their interests or needs change over time, making it more challenging to adapt to raised beds with or without framing. Therefore, it’s better to use ground-level gardens and create pathways around your garden beds.

Does a raised garden bed need a foundation?

To create a garden bed, start by finding level ground in your garden or on a deck, footpath, or driveway. If the base is on grass, remove the dead grass before adding aggregate and soil. Next, start “lasagna gardening” by adding layers of healthy, fertile soil and aggregate that drains well. Fill the drainage layer with organic matter from around the home, such as cardboard packaging or leaves, logs, and sticks, but check the growing requirements of the plants you plan to grow.

What should you not put in a raised garden bed?

Raised beds are ideal for growing a wide variety of edible plants, but not all plants can or should be grown in them. Some plants grow too large for raised beds, such as potatoes, asparagus, artichokes, rhubarb, corn, wheat, rice, and winter squash. Raised beds can be challenging to maintain due to the need for ladders, which can be dangerous for harvesting plants. It is essential to consider the specific needs of each plant when choosing a raised bed, as not all plants can thrive in raised beds. Therefore, it is essential to carefully consider the type of plant and the space available for each plant to ensure the best growth and care.

Do you need to put anything under a raised garden bed?

To protect your garden from pests, consider adding a liner at the bottom of your raised garden bed. This barrier prevents common digging pests like moles and gophers from entering the bed, causing damage to your plants. A heavy-duty option like hardware cloth can deter these pests. A liner also helps prevent temperature fluctuations, as the soil in a raised bed loses or gains heat more quickly than the ground soil. It provides a buffer or insulation, protecting the soil against rapid temperature changes.

Additionally, consider adding a greenhouse cloche over your plants to protect them from cooler temperatures, especially in early spring or fall when overnight frost can damage or destroy plants. By implementing these measures, you can ensure your garden remains safe and healthy for your plants.

What do you put on the bottom of a raised garden bed?

Cardboard or newspaper can be used to line the bottom of raised garden beds to deter pests and weeds on a budget. Choose cardboard with minimal markings and no tape for a safer option. Stainless steel gopher nets can be used for extra protection, as seen in Vego Garden’s modular cover system. Landscaping fabric can prevent soil erosion, promote water retention, and keep out invasive grasses. While it doesn’t break down over time like cardboard, it limits shallow-rooted plant growth, earthworm movement, and soil mixing. Deeper beds may not need it unless a weed problem is present.

Why do you put cardboard under a raised bed?

Earthworms thrive in a damp environment created by cardboard, which can be used in raised beds and vermicomposting bins. To repurpose surplus cardboard, line it on the bottom of raised garden beds to block out weeds and act as a barrier against rhizomatous, weedy, or invasive plants. Using dye-free or recyclable cardboard can help mitigate concerns about chemicals and glue compounds leaching into the soil. An organic stamp is a good indicator of its safety.

Plain cardboard with no tape and minimal markings is best for best results. Cardboard with glossy coatings or inks should be avoided. Most cardboard found around the house is safe to use. Using dye-free or recyclable cardboard can help reduce the amount of chemical substances in the soil.

What is the best base for raised garden beds?

Wide-mesh hardware cloth, stainless steel mesh, landscape fabric, burlap sack, or newspaper/cardboard can be used to line the bottom of raised garden beds. These materials keep weeds and burrowing animals out, but allow earthworms to pass through. Earthworms are nature’s gardeners, aerating and enriching soil for plants. Staple the cloth to the bed frame during construction and ensure it remains in place for years to come. This durable material is designed to prevent burrowing animals from affecting the bed frame’s functionality.

Can raised garden beds be placed on concrete?

A raised garden bed on concrete is not a guarantee of good drainage, as long as it is open on the bottom. A well-built raised bed on concrete drains faster than one sitting snugly within the soil, making it necessary to water it more often. Excess water from the bed will run to areas where rain water usually collects on the hard surface, such as a drain system, a slight slope, or a depressed area. However, this doesn’t mean a lot of water will flow out of the beds all the time.

A combination of tailored watering practices, quality soil with adequate drainage and good moisture retention, and the right bed height (taller is better) can help the bed retain most of the water it provides. When watering, ensure the soil is consistently damp, but avoid overwatering to avoid water pouring out from the bottom.