SproutSmart
SproutSmart Intelligent Garden Sowing

Super Star

Onion
Botanical illustration of Super Star
🌱 110d to harvest Bulbing

Aromatically sweet at first touch, Super Star onions develop a mellow, golden depth with a crisp snap and a finely layered, tende…

Planting Schedule

Add Super Star to your garden to build a schedule and get reminders.

Crop Dates

MilestoneDate
Start IndoorsOct 23rd
Last FrostJan 1st
Transplant / Sow OutdoorsDec 25th
Harvest BeginsApr 14th
Harvest Ends

Crop Details

TraitValue
Days to Maturity110
Sun RequirementsFull SunFull sun
Growth HabitBulbing
Support NeededNone
Planting DepthNormal
Germination Temp (°F)70
Min Soil Temp (°F)40
Min Night Temp (°F)28
Harden Off (days)7

Frequently Asked Questions


How do I prevent and treat onion (Allium cepa) downy mildew or purple blotch?
In onions (Allium cepa), downy mildew and purple blotch show as gray/whitish fuzzy patches or purple lesions on leaves, especially when nights are cool and foliage stays wet. Water at the base so leaves dry quickly, remove badly infected tops, and improve airflow by spacing bulbs properly. If problems start early, use a labeled onion fungicide and keep spraying on the label schedule until you see new growth staying clean.
How often should I water super star onions during the main bulbing phase?
During bulbing (often after seedlings establish and days length increases), keep soil consistently moist but not soggy—aim for about 1 inch (2.5 cm) of water per week total from rain and irrigation, adjusting for heat and soil drainage. Let the top 1–2 inches of soil dry slightly between waterings to prevent rot, then water deeply to encourage strong root systems. Once tops begin to yellow and fall naturally, reduce watering to help bulbs finish and cure.
When are super star onions ready to harvest, and how can I confirm it?
Harvest when about 50–70% of tops have fallen over and the remaining leaves are yellowing, typically around 110 days for this type of Allium cepa. Lift a few bulbs first to check: skins should feel papery and tight, and the bulb neck should be firm. Cure harvested onions in a warm, airy spot for 1–2 weeks until outer skins are fully dry, then trim roots and tops for storage.
Botanical illustration of Super Star

Aromatically sweet at first touch, Super Star onions develop a mellow, golden depth with a crisp snap and a finely layered, tender bite. Their intermediate-day timing brings dependable bulbs to the garden in about 110 days, forming well-rounded shapes with a handsome, papery sheen that stores with confidence. Grow Super Star for bold flavor in everyday cooking, from roasting and sautéing to savory sauces and pickling brines—an all-purpose onion that stays vibrant from harvest through the season.

Sowing Tips

Transplant Conditions

Wait until soil reaches 40°F and nights stay above 28°F before moving outdoors. Harden off for 7 days first.

Expert Note

For sweet, uniform white bulbs, keep soil evenly moist after seedlings establish and avoid letting plants dry out or stall early.