Surface sow and press in lightly; requires light to germinate.
Seed To Bloom:
Recommended. Sow indoors 6-8 weeks before planting out and keep at 75°F until germination occurs, then at about 60-65°F. Water from below by placing containers/trays in a larger tray of water and allow to drain; this helps prevent damping off and disturbance of seeds.
Direct sow about 1-2 weeks after the last frost for flowers mid-summer to fall.
WHEN TO SET OUTSIDE
1-2 weeks after last frost.
PLACEMENT & CULTIVATION
Ageratum was introduced to England from Veracruz, Mexico by Dr. William Houston, who first collected the species in the 1700s. This reliable summer border favorite has handsome foliage and clusters of long-blooming fuzzy flowers that can withstand summer rains. When setting out into compost-enriched soil, pinch the plant to promote bushier growth, and mulch to conserve moisture. Deadheading is minimal but helpful to keep it looking fresh into fall.
Regular watering, 1" per week.
Not particular about pH levels.
Mix in about 2" of compost and organic time release fertilizer before planting.
Diseases & Pests:
Aphids may be an issue and can be controlled with insecticidal soap. Avoid powdery mildew by placing in a location with good air circulation. Do not grow in hot & humid conditions.
When to Cut for Bouquets:
Harvest when 1/2- to 3/4 of the flowers in the cluster are open.