Yellow Spanish

Onion

Zone 12b Save Garden

Botanical illustration of Yellow Spanish

🌱 110d to harvest Bulbing

Sunlit and bold, Yellow Spanish onions bring a bright, golden skin that glows even before you peel—firm, crisp layers promising a…

Crop Dates

Milestone	Date
Start Indoors	Direct Sow
Last Frost	Jan 1st
Transplant / Sow Outdoors	Jan 1st
Harvest Begins	Apr 21st
Harvest Ends	Dec 31st

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

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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.

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.

Sowing Tips

Transplant Conditions

Wait until soil reaches 55°F and nights stay above 28°F before moving outdoors.

Expert Note

For northern success, transplant young starts into cool soil early, and stop fertilizing nitrogen once bulbs begin to form to keep them sizing up instead of staying leafy.