Yellow Sweet Spanish

Onion

Zone 5b Save Garden

Botanical illustration of Yellow Sweet Spanish

🌱 120d to harvest Bulbing

Sunlit and sweet from the first bite—Yellow Sweet Spanish brings a gentle, honeyed flavor with a tender, juicy bite and a crisp, …

Crop Dates

Milestone	Date
Start Indoors	Mar 23rd
Last Frost	May 4th
Transplant / Sow Outdoors	May 4th
Harvest Begins	Sep 1st
Harvest Ends	Oct 5th

Crop Details

Trait	Value
Days to Maturity	120
Sun Requirements	Full Sun
Growth Habit	Bulbing
Support Needed	None
Planting Depth	Normal
Germination Temp (°F)	70
Min Soil Temp (°F)	50
Min Night Temp (°F)	35
Harden Off (days)	7

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Frequently Asked Questions

What pest or disease commonly affects Allium cepa (yellow sweet Spanish onions), and how do I control it?

Onions (Allium cepa) are prone to purple blotch (Alternaria porri) and downy mildew, which show as purplish blotches or gray/purple fungal growth on leaves, especially after cool, humid weather. Cut off and discard heavily affected leaves early, improve airflow, and avoid wetting foliage when watering. If problems spread, apply an onion-safe fungicide labeled for Alternaria/downy mildew and keep treatments timed to rainy periods.

How often should I water Allium cepa during the main growing phase, and what soil moisture target should I aim for?

During the bulbing growth phase (roughly mid-season), keep soil evenly moist but not waterlogged—aim for about 1 inch of water per week depending on rainfall and heat. Let the top 1–2 inches of soil dry slightly between waterings so the bulbs form well, then resume steady moisture. When bulbs start to thicken and the tops begin to slow, gradually reduce watering to prevent rot.

How can I tell when Allium cepa (yellow sweet Spanish onions) are ready to harvest?

Harvest when about half of the onion tops have fallen over and the necks feel soft but not still actively growing, typically around 120 days. Lift a few sample bulbs to check: mature bulbs should have full size and dry, papery skins. Stop watering about 1–2 weeks before harvest to help skins cure in the field and reduce storage rot.

Sunlit and sweet from the first bite—Yellow Sweet Spanish brings a gentle, honeyed flavor with a tender, juicy bite and a crisp, clean snap. Its golden skins and well-filled bulbs store beautifully for long season enjoyment, making it a favorite for fresh use, roasting, and caramelizing into silky sweetness. Grow it for those moments when you want onions that taste as bright as they look—boldly flavorful yet never harsh.

Sowing Tips

Transplant Conditions

Wait until soil reaches 50°F and nights stay above 35°F before moving outdoors. Harden off for 7 days first.

Expert Note

For long-day Spanish onions, grow strong seedlings (sturdy tops, not tall/spindly) and transplant into cold soil as soon as workable to keep plants from bolting.