Sunflower (Asteraceae): General Blooming Period, Daily Peak Blooming Time, and Sowing Period

The sunflower is an annual herbaceous plant of the genus Helianthus in the Asteraceae family. It is cultivated throughout China. Sunflower seeds are called sunflower seeds (kuihua zi) and are often roasted and eaten as a snack. So when does the sunflower generally bloom? At what time of day does it bloom the most? And when is the best time to sow it? The details are compiled below:

Sunflower Blooming Time

Sunflowers are generally sown in April, bloom from July to August, and their seeds mature from August to September. The flowers mostly open between 4 and 6 in the morning.

Sunflowers can be grown in all four seasons, mainly in summer and winter. The blooming period can last more than two weeks. Besides its appearance, which closely resembles the sun, the sunflower's blooms are bright and generous, making it suitable for ornamental display, and its seeds have even greater economic value: they can be made into the popular sunflower seeds snack and can also be pressed into a low-cholesterol, premium edible sunflower oil. Sunflower varieties can be divided into "general ornamental" varieties and "edible" varieties. General ornamental varieties are characterized by being shorter, usually no more than half a meter, and are therefore suitable for growing in pots; edible varieties are taller, grown in ordinary open-field nursery soil, and can reach more than 2 meters. Sunflowers grow quite rapidly, usually blooming about two months after planting. Their flower forms include single-petaled, double-petaled, single-flowered, and multi-flowered types, and the blooming period is quite long, reaching more than two weeks.

Sunflowers are not demanding about soil and can grow in all kinds of soil, from fertile soil to dry land, poor soil, and saline-alkaline land. They have a strong tolerance for salinity and alkalinity.

What Month Are Sunflowers Generally Sown?

How to Grow Sunflowers

Part One: Seeds

To cultivate seeds, first soak them in warm water, then plant them in the soil with the pointed end facing down; they will sprout in about 4 to 5 days.

Part Two: Sowing

1. Sowing time: sowing can be done once the soil temperature at a depth of 125px reaches 5°C. The basic principles for choosing the sowing time are: first, according to the patterns of salinity and alkalinity, sow appropriately early or late so that the seedlings avoid salinity and alkalinity damage; second, carry out spring or summer sowing according to the variety's growth period; third, adjust the sowing time according to the patterns of disease occurrence so as to avoid the season when diseases are most prevalent; fourth, adjust the sowing time according to growth characteristics so that the flowering and grain-filling period avoids high temperatures above 28°C.

2. The germination rate and seedling emergence rate of confectionery sunflower are lower than those of oilseed sunflower, and its ability to push through the soil is also inferior to that of oilseed sunflower. To ensure the number of emerged plants, the actual sowing rate should be increased by 10-20% over the calculated sowing rate. Confectionery sunflower has a very strong self-regulating ability: with high planting density, the flower head is small and the seeds are small; with low density, the flower head is large and the seeds are also large. On the premise of ensuring both yield and marketability, the number of plants retained per 667 sq m should preferably be maintained at around 3,000 plants, with a row spacing of 60-1750px and a plant spacing of 30-875px. The sowing rate is determined according to variety characteristics and cultivation requirements. Generally, manual dibbling requires 600 grams of seed per 667 sq m, and machine sowing requires 700 grams.

3. Seed fertilizer: confectionery sunflower has a relatively long growth period and tall plants. The seed fertilizer rate is 5-8 kg of diammonium phosphate per 667 sq m applied in holes or bands, or 10 kg of triple superphosphate.

4. Sowing method: soil moisture should be good at sowing time, and a depth of 3-100px is suitable. The sowing methods used are:

① Making beds by hand or machine, then dibbling or drilling in furrows;

② Precision dibbling, with 1-2 seeds per hole. In arid areas, the method of deep furrowing and shallow covering can be adopted, sowing the seeds on moist soil with good moisture content.

Part Three: Sowing Conditions

Sowing time for sunflowers: March to April.

Suitable temperature for sowing: 18-25°C.

Sprouting time: 5-7 days.

Sowing method: dibbling, covering with about 25px of soil; flowering occurs about 50-80 days after sowing, with slight differences depending on the variety. Adverse symptoms.

Part Four: Field Management

Field management is an important step in cultivating robust plants and achieving high quality and high yield. As the saying goes: "Three parts planting, seven parts management."

1. Inspecting the field and filling in gaps: the sunflower is a dicotyledonous crop, and pushing through the soil to emerge is relatively laborious. In addition, poor land preparation, poor sowing quality, soil crusting after rain following sowing, or damage from diseases, insects, rodents, and birds can all easily cause missing plants and broken rows. To ensure full emergence after a single sowing, inspections must be carried out field by field and row by row during the emergence period; if plants are missing in patches or rows, reseeding must be done in time, soaking the seeds to hasten germination until they show white sprouts and then reseeding promptly. Where few plants are missing, transplant from dense areas to sparse ones, lifting with soil attached (paying attention to the seedling's orientation toward the sun) and watering well to settle the roots; the survival rate can generally reach more than 95%. A portion of backup seedlings can also be raised to ensure the need for full stands.

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