How to Extend the Blooming Period of Calendula? A Detailed Guide to Practical Care Methods
1. After normal flowering in early spring, promptly cut off the spent flower stalks to encourage it to send out new shoots and bloom again, and strengthen water and fertilizer management; it can bloom again from September to October.
2. Sow in pots in early August, move to a temperature of 8°C to 10°C after frost, place outdoors in a wind-sheltered, sunny spot during the day, and place on an indoor sunny windowsill during severe cold. Water about once a week to keep the potting soil moist, and apply a compound liquid fertilizer once a month, so that it will keep blooming well into deep winter.
3. Sow directly in the courtyard at the end of March or the beginning of April, thin or transplant appropriately once the seedlings have emerged evenly, and provide reasonable fertilizer and water conditions; it can bloom in early June. Because calendula needs a relatively long low-temperature stage, spring-sown plants grow weaker and have smaller flowers than autumn-sown ones.
4. Sow in the open field in late August, control watering appropriately during the seedling stage, and cultivate strong seedlings. After winter begins, transplant them to a cold-protected, sunny spot to overwinter. When the temperature drops below 0°C, cover with straw curtains at night and remove them during the day. When the minimum temperature falls below -7°C, add a layer of plastic film under the straw curtains. At this time, only remove the straw curtains during the day and do not remove the film, but ventilate appropriately around noon on sunny days. When the minimum temperature rises above -7°C in early spring of the following year, remove the film promptly, and covering with straw curtains at night is sufficient. When the minimum temperature rises to 0°C, remove the straw curtains immediately. At this point, water appropriately to keep the soil moist, and topdress with dilute cake fertilizer water once about every 15 days, so that the calendula can bloom by the "May Day" holiday.
In addition, first place calendula seeds in a 0°C refrigerator for several days for low-temperature treatment, then sow them in the open field in early August, and they can also bloom in late September.