When to sow Calendula?

Calendula is a hardy annual that thrives in full sun or partial shade and tolerates a wide range of soil types, though it performs best in loam or sandy soil with good drainage. It's unfussy about fertility and actually flowers more profusely in moderately fertile ground than in overly rich soil. You can sow calendula directly outdoors from March through May for summer flowering, or in September for an early spring display the following year. Autumn-sown plants often overwinter successfully in zones 7–9 and produce stronger, earlier blooms. Prepare the soil by removing weeds and raking to a fine tilth. Sow seeds thinly, about 1 cm deep, either in drills or scattered in drifts. Calendula germinates readily in cool conditions—often within ten to fourteen days. Once seedlings have two or three true leaves, thin them to 25 cm apart to allow good air circulation and prevent mildew. You can transplant the thinnings if you handle them gently and water them in well. If you prefer to start plants indoors, sow in modules six to eight weeks before your last expected frost, then harden off and plant out after danger of severe frost has passed. Space transplants 25 cm apart. Water newly sown or transplanted calendula gently to settle the soil, but avoid waterlogging. A light mulch of garden compost helps retain moisture during establishment, though calendula's low water needs mean it copes well once settled. Staking is unnecessary; the bushy plants are self-supporting even in exposed sites.