🌸 Cosmos: Growing Guide
Cosmos (Cosmos bipinnatus) grows best in full sun with little water, and does well at 10–35 °C (50–95 °F) in soil with a pH of 6.0–8.0. Space plants about 30 cm (12 in) apart. Expect 60–80 days.
Quick facts
| Scientific name | Cosmos bipinnatus |
|---|---|
| Category | Flowers |
| Sunlight | Full sun |
| Watering | Low |
| Plant spacing | 30 cm (12 in) |
| Soil pH | 6.0–8.0 |
| Comfortable temperature | 10–35 °C (50–95 °F) |
| Time to maturity | 60–80 days |
| Sowing depth | 0.5 cm (0.2 in) |
| Height | 60–150 cm (24–59 in) |
When to sow, plant and harvest
The calendar below shows the best months in each climate zone. Pick the zone closest to your garden.
| J | F | M | A | M | J | J | A | S | O | N | D | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mediterranean | Sow | Plant out | Harvest | Harvest | Harvest | Harvest | ||||||
| Continental | Sow | Plant out | Harvest | Harvest | Harvest | |||||||
| Oceanic | Sow | Plant out | Harvest | Harvest | Harvest | |||||||
| Subtropical | Sow | Plant out | Harvest | Harvest | Sow | Plant out | Harvest | |||||
| Tropical | Plant out | Harvest | Harvest | Plant out | Plant out | Harvest | Harvest | |||||
| Cold / Northern | Sow | Plant out | Harvest | Harvest | ||||||||
| Arid / Semi-arid | Sow | Plant out | Harvest | Harvest | Sow | Harvest |
- Mediterranean (Greece, Spain, Italy, coastal Turkey): Sow: Mar · Plant out: Apr · Harvest: May–Aug.
- Continental (Central/Northern Europe, inland Balkans): Sow: Apr · Plant out: May · Harvest: Jun–Aug.
- Oceanic (UK, France, Belgium, Netherlands, NW Europe): Sow: Apr · Plant out: May · Harvest: Jun–Aug.
- Subtropical (Southern US, N. Africa, Middle East): Sow: Jan, Aug · Plant out: Feb, Sep · Harvest: Mar–Apr, Oct.
- Tropical (SE Asia, Sub-Saharan Africa, Amazon): Plant out: Jan, Jul–Aug · Harvest: Feb–Mar, Sep–Oct.
- Cold / Northern (Scandinavia, Canada, Russia, Alpine): Sow: May · Plant out: Jun · Harvest: Jul–Aug.
- Arid / Semi-arid (Arabian Peninsula, inland Australia): Sow: Feb, Aug · Plant out: Mar · Harvest: Apr–May, Sep.
Watering
Water about every 4 days in summer and about every 10 days in winter. Hardy, little water.
Growing tips
Delicate, airy flowers. Self-seeds. Attracts hoverflies — beneficial insects!
Good companion plants
These plants grow well alongside it:
Common pests and problems
Frequently asked questions
Cosmos: when should I sow and plant it?
Mediterranean (Greece, Spain, Italy, coastal Turkey): Sow: Mar · Plant out: Apr · Harvest: May–Aug. Continental (Central/Northern Europe, inland Balkans): Sow: Apr · Plant out: May · Harvest: Jun–Aug. Oceanic (UK, France, Belgium, Netherlands, NW Europe): Sow: Apr · Plant out: May · Harvest: Jun–Aug.
Cosmos: how often should I water it?
Water about every 4 days in summer and about every 10 days in winter. Hardy, little water.
Cosmos: how far apart should I plant it?
Plant about 30 cm (12 in) apart and sow at a depth of about 0.5 cm (0.2 in).
Cosmos: how long does it take to grow?
Plan on 60–80 days.
Cosmos: which plants grow well with it?
Velvet, Zinnia.
Cosmos: which pests and problems should I watch for?
Aphids.
Plan your garden
Add Cosmos to your garden design in the free GardenXPro planner: drag plants onto a 2D plan, preview it in 3D, check companions and get watering reminders.
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