Calypso Onion

Onion

Zone 6a Save Garden

🌱 120d to harvest Bulbing

Sweetly aromatic and richly savory, Calypso Onion forms handsome, well-filled bulbs with a balanced bite that turns mellow in the…

Crop Dates

Milestone	Date
Start Indoors	Mar 6th
Last Frost	May 1st
Transplant / Sow Outdoors	May 1st
Harvest Begins	Aug 29th
Harvest Ends	Oct 10th

Crop Details

Trait	Value
Days to Maturity	120
Sun Requirements	Full Sun
Growth Habit	Bulbing
Support Needed	None
Planting Depth	Normal
Germination Temp (°F)	75
Min Soil Temp (°F)	45
Min Night Temp (°F)	28
Harden Off (days)	5

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Frequently Asked Questions

What pest or disease is most likely to affect Allium cepa (Calypso onion), and how can I treat it?

Onions (Allium cepa) commonly suffer from downy mildew, which shows as gray-purple fuzzy growth on leaves and can rapidly weaken plants. Improve airflow by spacing bulbs properly and avoid watering the foliage; if you see symptoms, remove heavily affected tops and treat remaining plants with a labeled fungicide for downy mildew on onions. Keep beds weed-free because volunteer alliums and weeds can harbor spores.

How often should I water Calypso onion during the main growing phase?

During active leaf growth, keep soil evenly moist but not soggy—aim for about 1 inch (2.5 cm) of water per week, adjusted for rainfall and heat. Water deeply when the top 1–2 inches of soil dry out, since onions form best when moisture is steady rather than frequent light watering. Stop or sharply reduce watering as bulbs start bulking (late season) to help skins cure and prevent rot.

How do I tell when Calypso onion is ready to harvest?

Harvest when about half the plants have fallen over and the necks are soft but not green. Lift bulbs gently (don’t yank) once tops are dying and skins have turned papery; onions will store much better if you harvest at this stage. After harvest, cure them in a warm, airy spot until outer skins are fully dry and rustling.

Sweetly aromatic and richly savory, Calypso Onion forms handsome, well-filled bulbs with a balanced bite that turns mellow in the pan and shines in everyday preparations. The skin is a warm golden-brown with a tidy, papery finish, while the crisp interior layers offer a fine, juicy texture ideal for slicing and layering. Grow Calypso for dependable, intermediate-day performance and a dependable harvest that’s as beautiful on the counter as it is in the garden.

Sowing Tips

Transplant Conditions

Wait until soil reaches 45°F and nights stay above 28°F before moving outdoors. Harden off for 5 days first.

Expert Note

For mild, sweet, marketable bulbs, keep soil evenly moist and plant transplants deep enough to anchor the base while leaving the neck just above the soil line.