(1) Seed preparation. The seeds of calendula are actually achenes in botany, and the seed sizes vary greatly. The 1000-grain weight of good seeds can reach about 1 1g, and that of small seeds is only about 4.5g, usually 8-9g. Try to use larger seeds to raise seedlings, sow in autumn or raise seedlings in early spring, and the seeds planted in early spring will develop well. Marigold is easy to deteriorate, so inferior plants should be eliminated as soon as possible before seed collection. Achenes can be harvested when the inflorescence disc edge begins to turn yellow stone, and it is easy to fall off when harvested late. Sowing and seedling raising, in Fushun area, the seeds will mature in the first half of June, and they should be dried in time after harvest. Seeds can be used for 2 ~ 3 years.
(2) days of seedling raising. It takes 60 to 80 days to produce flowering seedlings in early spring. Sow in summer and cultivate in autumn for 45-55 days, but the growth of seedlings is relatively small. Sowing in autumn, wintering in cold bed and planting in spring in South China.
(3) Sow seedlings in spring. Calendula seedlings can tolerate frost and can be planted some time before the final frost. Sow 60 ~ 80 days before sowing. The calcareous nutrient soil for common nutrient soil seedling growth is good, and the suitable pH is 6.5 ~ 7.5. The seed germination rate of calendula is often not very high, so germination test should be done. Under the condition of relatively high germination rate, the sowing amount per square meter of seedbed with large seeds is 60 ~ 80 grams. The seeds should be covered with fine soil of 1.2 ~ 1.5 cm, not too shallow, so as not to be unearthed with seed coat. Sow the dried seeds at a suitable temperature for 6 days until they emerge. 1 ~ 2 transplant seedlings when the true leaves grow, cultivate them in containers with a diameter of 8 ~ 9 cm, or furrow them. The temperature should be controlled at 15 ~ 25℃ during the day and at 5 ~ 15℃ at night, so the temperature should not be too high, which is lower than that of most herbaceous flower seedlings. The seedling stage should be fully illuminated and the water content should be controlled moderately. 5 ~ 7 days before planting, reduce the temperature, increase ventilation, and moderately control water to refine seedlings. Planting before and after the final frost. When the seedlings are planted, the growth amount is large and the development is good, and the flowers become obviously larger after planting.
(4) Sowing in autumn. Seedbed sowing should be done outdoors in autumn. If the ground temperature is too high, which is not conducive to seed germination, the seeds can be placed at 0℃ for 65438 0 days and then sown. The seedbed should be properly shaded to avoid heavy rain hitting the seedbed before emergence. Transplant seedlings when there are 2 ~ 3 leaves. In winter, when overwintering in a cold bed, small seedlings can endure the temporary low temperature of -9℃, and large seedlings are vulnerable to freezing injury. Seedlings that have undergone cold bed exercise at low temperature can be planted early and have large flowers.