How to Plant Sunflower Seeds? A Detailed Guide to Sowing Time and Methods
The sunflower is an annual herbaceous plant of the genus Helianthus in the Asteraceae family. It is cultivated throughout China. So how do you plant its seeds? When should you sow them? What are the planting methods? According to a sunflower planting base in Shanxi, sunflowers have strong low-temperature tolerance at both the seedling stage and the mature stage. The seeds begin to swell and sprout at 2°C—4°C, can germinate at 4°C, can emerge at 5°C, and 8°C—10°C is enough to meet the needs of normal emergence. The sowing time is generally from late March to mid-April. Either direct sowing or raising seedlings for transplanting works. The planting density is 65 cm × 60 cm, with one plant per hole.
How to Plant Sunflower Seeds (In Pots)
Pre-sowing Treatment:
1. Seed selection before sowing: Select the seeds before sowing and remove shriveled grains and impurities. This can also effectively increase the emergence rate.
2. Sun-drying the seeds before sowing: Before sowing, choose a sunny day and spread the seeds out to dry for 2-3 days. This lowers the moisture content of the kernels, raises their temperature, strengthens enzyme activity within the seeds, promotes after-ripening, enhances vitality, and improves germination vigor and germination rate, which helps the seeds germinate quickly and emerge evenly after sowing.
3. Chemical seed dressing: To prevent damage from underground pests and the occurrence of sunflower diseases and to improve the emergence (and survival) rate of sunflowers, it is best to use 600 g of phorate per mu, evenly mixed with seed fertilizer for soil treatment, or dress the seeds with 0.3% abamectin, or dress the seeds with phoxim emulsifiable concentrate, water, and seeds in a ratio of 1:40:500. When dressing the seeds, spray the chemical while stirring so that the liquid thoroughly soaks the seed coat, then dry the seeds in the shade in time before sowing.
4. Seed soaking and sprout forcing: Both seed soaking and sprout forcing can shorten the time the seeds need to absorb water and swell in the soil, bring about earlier emergence, gain more growing days, hasten maturity, and avoid reduced yields from freezing damage after autumn. The specific methods are as follows: Warm water soaking: Soak sunflower seeds in 18°C warm water. Soak edible varieties for 6-12 hours and oil varieties for 6-8 hours. After removing them, dry them until about 70% dry and they are ready to sow. If sprout forcing is needed, remove the soaked seeds, place them in a plastic bag, and pile them in a warm room overnight. When the seed coats of some seeds begin to show white and most of the seeds have begun to sprout, they are ready to sow (they must be sown in a plot with good soil moisture, otherwise the sprouts may easily fail).
After the Seeds Germinate:
1. Wait until the sunflower seeds germinate, push up through the soil surface, and open their cotyledons, then they can be transplanted into a large pot. After transplanting, water thoroughly to settle the roots; be sure to water until it soaks through. It is recommended to place them indoors in a sunny spot. If you want to put them under the sun, you will need to water them frequently.
2. Wait until about 3 to 4 pairs of true leaves have grown, then spray some monopotassium phosphate on the leaves every few days to promote plant growth. Sunflowers need fertilizing during growth, and at this time be sure to use only fully decomposed organic fertilizer.
What Are the Methods for Planting Sunflowers?
1. Site selection: Choose deep soil, level land, and matching irrigation and drainage. A crop rotation period of 3—4 years or more is required, and continuous cropping on the same land is strictly prohibited.
2. Land preparation and fertilizing: Prepare the land finely and apply sufficient base fertilizer. There must be no stubble before sowing. Apply heavy base fertilizer and deep-apply seed fertilizer. In autumn, plow deeply 20—625px and apply 1000—1500 kg of farmyard manure per mu. On the basis of pressing in the base fertilizer in autumn, carry out autumn irrigation at the right time. On the basis of timely rolling and harrowing in winter and spring, level the land and build banks to reduce plot size before sowing (1—1.5 mu per plot), so that the land is level, the soil is fine, and soil moisture is uniform. Before sowing, deep-apply 10—15 kg of diammonium phosphate, 7—8 kg of potassium fertilizer (potassium chloride or potassium sulfate), or a nitrogen-phosphorus-potassium compound fertilizer along the rows of edible sunflowers.
3. Before sowing, sun-dry the seeds for 2—3 days. Use 150 mL of 40% phoxim, diluted with 5—7.5 kg of water, to dress 25—30 kg of seeds to prevent underground pests. Soak the seeds in a 500-fold carbendazim solution for 6 hours, or dress the seeds with dimethachlon or thiophanate-methyl, etc., at a rate of 0.5—0.6% of the seed weight, to prevent sclerotinia.
4. Use hole sowing or open furrows with a drill for manual spot sowing at fixed spacing. On clay soil, sow at a depth of 82.5px; on sandy loam and sandy soil, the sowing depth can reach 4—150px. The sowing time for sunflowers is generally set so that spring sowing is preferable early. The sowing method is mainly manual hole sowing. In hole sowing, the seeds can be dropped according to the required plant spacing, with a sowing depth of about 5 cm. Generally, the seeding rate for hole sowing is 1—1.5 kg per mu, with 4—5 seeds per hole, using wide-and-narrow row sowing: 100 cm between wide rows, 50 cm between narrow rows, and 60 cm between plants, leaving about 1400 plants per mu.