In Northern New Hampshire, When May I Plant Sunflowers?

In New Hampshire, it is essential to pay close attention to local weather in spring, particularly when the last frost occurs. In warm regions, sunflowers can be planted as late as August, while in cold, northern climates, fast-growing varieties can be planted as late as July for a harvest before the first frost hits in early fall.

There are three options for planting sunflowers: early spring, mid spring, and winter. For northern regions with short growing seasons, planting sunflower seeds after the last average spring frost date ensures optimal conditions. The ideal time to plant sunflowers depends on whether the plant is a perennial, annual flower, or bulb, and whether it is frost-sensitive or not.

The ideal time to plant sunflowers is after the risk of frost has passed and soil temperatures are 70° to 75°F (21° to 25°C). Direct sowing of sunflower seeds is best after the danger of spring frost has passed, anytime after soils have warmed to at least 50°F (10°C). In the northern half of the U.S. and Canada, this will fall between April and mid-June.

Sunflowers need full sun and grow best in fertile, well-drained, moist soil with plenty of mulch. They do not like to be transplanted, so they are best grown in their natural environment.

Planting sunflowers between late June and early/mid-July is recommended, depending on the days to maturity (dtm). Seeds can be sown successfully from January to June for flowering during summer and the rainy season. After several days, transplants should be spending 24 hours outdoors and ready to be planted into the ground once the threat of frost has passed.

In summary, planting sunflowers in New Hampshire requires careful consideration of local weather, frost risk, and soil temperature.

How long do sunflowers take to germinate?

The germination of sunflower seeds occurs within a period of seven to ten days, contingent upon the prevailing soil temperature and moisture levels. In the majority of cases, the emergence of sprouts occurs within this timeframe. Should seed production be desired, the seedlings should be thinned to a distance of 2 to 3 feet apart after the second set of leaves has emerged.

What is the coldest temperature sunflowers can tolerate?

Sunflower heads turn yellow as they grow, reducing frost damage risk. At the R7 stage, sunflowers can withstand temperatures as low as -4°C with minimal damage. A frost duration of 6 hours or more below 25°F can cause damage, resulting in losses in yield, test weight, reduced oil content, and discolored seeds. Stage R8 occurs when the backs of the flower heads are completely yellow but the bracts remain green. Frost damage at this stage may result in some reduction in yield, test weight, and oil content, but most seeds are marketable.

How to plant sunflowers in New England?

Sunflowers can be sown directly into the ground, planting seeds no more than 1 inch deep and 6 inches apart. Multiple seeds can be sown to determine the strongest seed, and removed once they reach 6 inches tall. Water around the root zone while the sunflowers are small, then water deeply once a week to encourage deep root growth. Plant nutrients like SUPERthrive can also be beneficial for sunflowers.

What is the best temperature to plant sunflowers?

Sunflowers thrive in temperatures between 70-78°F (21-26°C), but can survive higher temperatures with adequate water. They can grow in cool, sunny climates but cannot survive exposure to temperatures below 26 to 23°F for 6 hours. Choosing the right field with proper sunlight and temperature is crucial for healthy crop growth. EOSDA Crop Monitoring allows farmers to assess potential using daily temperature data and past active temperatures.

Sunflowers can grow in various soil types, but optimal yields are achieved on neutral soils with a pH between 6. 5 and 7. 5 and adequate drainage. If the soil pH is below 5. 5, lime can be added. The best soil for sunflowers is sandy loam, but clay loam or silty clay can be used.

How to tell if sunflower seeds are good for planting?

Sunflower seeds can be harvested at the end of the season for re-planting, baking, or repurposing into suet cakes for winter bird feed. They are ready when their foliage turns yellow, petals die down, and the seeds look plump. To harvest sunflower seeds, remove the seeds by rubbing the seed head over a bucket, removing petals and other sunflower matter. If re-planting or making suet cakes, rinse the seeds in a colander and remove any non-seeding parts.

Line a shallow cardboard box or wooden crate with newspaper and paper towels and scatter the seeds in a single layer to dry. Allow the seeds to dry for several hours or overnight. If saving for re-planting, store them in an airtight container in a cool, dry place until ready to plant. Label the container with the variety and the date you harvested, as the seeds will last for years if stored this way.

Do sunflowers have to face east?

Sunflowers face east due to their ability to track the sun during the day, which is controlled by the plant’s internal circadian clock. As the flower heads mature and their stems become stiff, this movement decreases until the heads face the morning sun. Postdoctoral researcher Nicky Creux found that east-facing sunflowers attracted more bees, especially in the morning, when their pots were turned around, indicating that sunflowers face east is better for producing more offspring.

How long does it take for a sunflower seed to sprout?

The germination of sunflower seeds occurs within a period of seven to ten days, contingent upon the prevailing soil temperature and moisture levels. In the majority of cases, the emergence of sprouts occurs within this timeframe. Should seed production be desired, the seedlings should be thinned to a distance of 2 to 3 feet apart after the second set of leaves has emerged.

At what temperature do sunflowers germinate Celsius?

The study examined the germination of sunflower seeds at various temperatures, with the highest germination rate observed at 25°C. Early germination occurred at 20°C and 25°C, but the growth rate was lower at 20°C. Sunflower seeds took longer to germinate at low temperatures, taking approximately 19 days at temperatures 5 and 10°C. The minimum temperature of germination ranged between 5 and 10°C, while the maximum ranged between 35 and 40°C.

The recording data of radicle and shoot growth patterns under different temperature levels showed that 15°C, 20°C, 25°C, and 35°C are optimal for seedling development. The shoot grew optimally at 25°C, while the radicle grew optimally at 15-25°C. Radicle growth was more significant and rapid at 10°C than shoot growth. The shoot and radicle, particularly the radicles, do not require prolonged exposure to elevated temperatures. Their growth was poor at 5°C and nonexistent at 35°C.

The results indicated that growth was highest at 25°C, followed by 15°C, 20°C, and 35°C. Therefore, 25°C was ideal for seedling development. At 20 and 35°C, similar development trends were found, but seeds germinated earlier at 20°C. An overlapping temperature pattern was detected between 15 and 20°C during the growth phase. At 10°C, seedling growth was gradual, but at 5°C, growth was stable but significantly hindered, requiring additional development time. The lowered length value at 35°C and the absence of germination at 40°C demonstrated that temperature elevations above the optimal were detrimental to seedling development.

What’s the earliest you can plant sunflowers?

Sunflower seeds should be planted between April and May in 10cm pots of peat-free, multi-purpose compost. Cover the pots with a plastic bag and place them in a warm spot for optimal germination. Once the seedlings emerge, harden them off gradually for two to three weeks before planting them outdoors. If your garden has a lot of slugs and snails, consider potting them into larger pots of fresh compost and hardening them before planting them.

This will make the plants more resilient to slugs and snails. Plant seedlings when the soil has warmed considerably and the frost risk is gone. Monty Don’s giant sunflower trial is a great example of how to sow sunflower seeds.

Should I soak sunflower seeds before planting?

Soaking seeds before planting is a common method to improve germination, as seeds have a hard outer layer to protect themselves from insects and diseases. Soaking them in water softens the hard seed coat, exposing the embryo to moisture and promoting growth. Sunflower seeds don’t need to be soaked, but soaking them for 12 to 24 hours can hasten germination and increase the number of sprouts. To grow sunflowers outdoors, cover the planting area with finished compost or aged manure, then work it into the ground, loosening the top 12-18 inches of soil. This loose soil allows the sunflower’s long taproot to grow easily and improves water infiltration.

When to plant sunflowers in New Hampshire?

Sunflowers can be directly seeded in the garden after the last frost, or they can be started indoors 2-3 weeks before the last frost. To protect them from deer, it is recommended to provide a fence. The timing of starting sunflowers depends on the number of days it takes for them to reach maturity, which can range from 50 to 95 days. Choosing a pollenless (hybrid) branching variety and planting a few weeks apart is recommended to ensure the sunflowers are ready for harvest.

It is important to consider that the growth of sunflowers may slow down in September, so plantings should be done between late June and early/mid-July. Popular hybrid varieties include Gold Rush (60-65 dtm) and Soraya (85-95 dtm).