How to prolong the flowering period of Calendula

First, after normal flowering in early spring, cut off the stump pedicels in time, promote its new branches to blossom, strengthen the management of water and fertilizer, and blossom again from September to October.

In the autumn sowing pot in the first ten days of August, it was moved to 8 ℃ ~ 10 ℃ after defrosting, and put outside in the leeward and sunny place during the day, and on the indoor sunny windowsill in severe cold. Watering once a week or so, keeping the basin soil moist, watering compound liquid fertilizer once a month, so that it can continue to blossom in the middle of winter.

Direct seeding in the courtyard at the end of March or the beginning of April, after the seedlings came out, the seedlings were properly interspersed or transplanted, given reasonable fertilizer and water conditions, and could blossom at the beginning of June. Because the marigold chrysanthemum needs a long period of low temperature, the growth of spring sowing plants is weaker than that of autumn sowing, and the flowers are smaller.

Fourth, autumn sowing in the open field in late August, timely control watering at the seedling stage, and cultivate strong seedlings. After entering the winter, transplant to the cold-proof and sunny ground to survive the winter. When the temperature drops below 0 ℃, cover the grass curtain to prevent the cold at night, and remove the grass curtain during the day. When the minimum temperature drops below-7 ℃, cover with a layer of plastic film under the straw curtain. At this time, only open the grass curtain during the day, not the film, but the sunny day around noon should be properly ventilated. When the minimum temperature rises to more than-7 ℃ in the early spring of the following year, remove the film in time and cover the grass curtain at night. When the minimum temperature rises to 0 ℃, the grass curtain should be removed immediately. At this time, appropriate watering to keep the soil moist, at the same time every 15 days or so to apply thin cake fertilizer water, so that the "May Day" marigold can open.

In addition, the marigold seeds were put in a 0 ℃ refrigerator for several days for low temperature treatment, and then sowed in the open field in early August, and could also blossom in late September.