Cosmos illustration

Cosmos Growing Guide

Asteraceae family

Days to Harvest55 days
SunlightFull Sun
Frost ToleranceNone
Spacing12/sqft
Germination5-10 days
HardinessTender
Germ. Temp75°F
Start Indoors4 weeks before last frost

Planting Dates by Zone

Zone 1aZone 1bZone 2aZone 2bZone 3aZone 3bZone 4aZone 4bZone 5aZone 5bZone 6aZone 6bZone 7aZone 7bZone 8aZone 8bZone 9aZone 9bZone 10aZone 10bZone 11aZone 11bZone 12aZone 12bZone 13aZone 13b

Frequently Asked Questions

How long does it take to grow Cosmos?

Cosmos takes approximately 55 days from planting to harvest.

How much sun does Cosmos need?

Cosmos requires full sun (6+ hours direct sunlight per day).

How far apart should I plant Cosmos?

Plant Cosmos at 12/sqft using square foot gardening spacing.

Can Cosmos survive frost?

Cosmos is frost-sensitive and should not be exposed to frost.

How long does Cosmos take to germinate?

Cosmos seeds germinate in 5-10 days at an optimal temperature of 75°F.

When should I start Cosmos seeds indoors?

Start Cosmos seeds indoors 4 weeks before your last frost date, then transplant 1 weeks after last frost.

Plan Your Cosmos Garden

Track Cosmos from seed to harvest with personalized frost dates, watering recommendations, and companion planting visualization.

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