Yellow Spanish

Onion

110d to harvest

Sunlit and bold, Yellow Spanish onions bring a bright, golden skin that glows even before you peel—firm, crisp layers promising a sharp, lively bite. At maturity they form generously sized bulbs with a classic flattened-oval silhouette and a dry, papery outer coat that stores beautifully. Grow Yellow Spanish for reliable harvests and for standout flavor in bold, slow-simmered sauces, roasting, and savory pickling preparations.

Crop Dates

Growing note: Frost-free Zone 12a supports continuous outdoor production.

Milestone	Date
Climate	Frost-Free Climate
Growing Approach	Continuous Production

Crop Details

Trait	Value
Days to Maturity	110
Sun Requirements	Full Sun
Growth Habit	Bulbing
Support Needed	None
Planting Depth	Normal
Germination Temp (°F)	70
Min Soil Temp (°F)	55
Min Night Temp (°F)	28
Harden Off (days)	Not Required

Frequently Asked Questions

What pest or disease most commonly affects Allium cepa (yellow Spanish onion), and how can I treat it?

Onions (Allium cepa) are especially prone to purple blotch/leaf blight (Alternaria porri), which shows as purple-brown spots on leaves and can spread during humid weather. Remove and discard badly infected leaves, improve airflow so foliage dries quickly, and apply a labeled fungicide for onions at the first signs of spots, repeating as directed on the label. Avoid overhead irrigation—water the soil at the base to reduce splash-spread.

How often should I water yellow Spanish onions during the main growing phase?

During active leaf growth (most of the 2–3 months after transplanting or when seedlings are established), keep the soil evenly moist but not soggy—about 1 inch of water per week total, split into 1–2 waterings depending on heat and rainfall. Let the top 1–2 inches dry slightly between waterings to prevent rot and root stress. Stop watering or sharply reduce once tops begin to fall over (late season) so bulbs dry and cure properly.

How do I tell when yellow Spanish onions are ready to harvest?

Harvest when about half of the onion tops have fallen over and the necks are starting to soften and dry, typically near your ~110-day maturity window. Gently lift one or two bulbs to check size and skin color—fully formed bulbs with papery outer layers are ready. Harvest on a dry day, then cure the onions in a warm, airy spot out of direct sun to firm the skins.