1/4-1/2". Tip: Nick or file the seed coat prior to soaking seeds in warm water for 24 hours prior to sowing.
Seed To Bloom:
Sow in pots about 4 weeks before last frost. Keep at 65-80°F. Cover with humidity dome to retain moisture until germination occurs.
Direct sow about two weeks after last frost.
WHEN TO SET OUTSIDE
After last frost, when soil has warmed.
PLACEMENT & CULTIVATION
Native to tropical regions, Ipomoea nil morning glories need a sheltered spot in warmth to grow well and flower. In longer season areas start indoors in individual pots, for their roots dislike disturbance, and set out into warm soil. Blooming starts later in mid-summer and continues until fall frost. An unusual cut flower, as long stems can be cut and placed in water. Under the dimmer light indoors, the flowers will stay open all day, then fade to be replaced with another bloom the next day. Caution: seeds contain some toxic alkaloids.
About 1" per week, more during especially dry, hot spells.
Slightly acidic to slightly alkaline.
Mix in 2" of compost prior to planting and apply a flower fertilizer at bud set for more abundant blooming. Avoid nitrogen fertilizers that favor foliage growth over flower development.