Open-Pollinated · 100–115 days from transplant
long-day · best for northern gardens
Grows well in
Raised Bed ✓
In-Ground ✓
Container/Pot ✓
Grow Bag ✓
Meet This Plant
Yellow Sweet Spanish is a big, beautiful onion with golden yellow skin, crisp white flesh, and a flavor that's mild and sweet enough to eat raw. The bulbs can reach a pound or more under good conditions and they store well for months after harvest.
This is a long-day onion, which means it needs about 14–16 hours of daylight to trigger bulbing. That's a latitude thing, not a zone thing. If your summers push past 14 hours of daylight, you're in good shape. Long-day onions are generally happiest in northern gardens. If you're a southern grower or just not sure, Texas Early Grano is the safer choice.
What it tastes like: Think of the onion you use for almost everything, only fresher. Mild enough to slice fresh, rich and sweet once it starts caramelizing, and the kind you'll end up adding to more meals than you planned.
Growing in a warm climate? Try Texas Early Grano →
How to Grow It
Sun
Full sun. Onions need as much light as you can give them. At least 6–8 hours of direct sun daily.
Water
About an inch of water per week. Consistent moisture produces bigger, sweeter bulbs. Reduce watering as the tops start to fall over so the outer skin can form properly before harvest.
Sowing Details
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Depth¼ inch
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Spacing4–6 inches for full-size bulbs
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Row Spacing12–18 inches
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ThinningThinnings can be harvested and used as green onions.
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Germination7–14 days. Buy fresh seed every season. Onion seed loses viability fast.
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Days to Maturity100–115 days from transplant
When to Plant
Start indoors 8–12 weeks before your last frost. Transplant out 4–6 weeks before your last frost when daytime temperatures are consistently in the 40s to 50s°F.
The goal is to get as much leafy growth as possible before the long summer days trigger bulbing. Bigger plants mean bigger bulbs.
Onions, don’t care how hot it gets. They care how long the days are. Yellow Sweet Spanish needs 14–16 hours of daylight to form bulbs. Southern gardens rarely get there, so you’d end up with leaves, not onions. Try Texas Early Grano instead.
Grow Friend Tips
Bigger transplants mean bigger bulbs
The more leaf growth your onion has before the long days trigger bulbing, the bigger the final bulb will be. Start seeds early, fertilize regularly while they're growing indoors, and get them in the ground as soon as conditions allow. Every week of extra growth before bulbing starts translates directly into a larger onion at harvest.
Buy fresh seed every season
Onion seed doesn't keep well. It's better to buy a fresh packet every season or you're gambling on germination.
Keep them weed free
Onions have shallow roots and do not compete well with weeds at all. A weedy onion patch means smaller bulbs. Keep the area clean from the moment you transplant and stay on top of it through the season. Mulching between rows helps a lot.
Stop watering when the tops start to fall
Once about half the tops have fallen naturally, stop watering and let the bulbs finish up in the ground on their own.
Cure them before you store them
After pulling, lay the onions out in a single layer somewhere warm, shaded, and well-ventilated for 2–4 weeks until the necks and skins are completely dry. Don't rush this step. Onions that aren't fully cured will rot in storage. Properly cured Yellow Sweet Spanish keeps 2–4 months.
Companion plants Carrots Lettuce Beets Chamomile Tomatoes Roses
Harvest & What to Do With It
When it's ready
Yellow Sweet Spanish is ready when the tops turn yellow and fall over naturally, typically 100–115 days from transplant. Once about half the tops have fallen naturally the onions are almost ready. Give it about a week then pull and cure them. The bulbs should be 4–6 inches in diameter at peak harvest.
How to harvest
Loosen the soil around the bulbs with a garden fork first, then pull by the tops. Handle them carefully because any bruising leads to rot in storage. Pull on a dry day if possible. Wet onions don't cure well.
Yield
One plant produces one bulb. A full packet at good spacing gives you a generous harvest of large sweet onions through the summer and into fall.
Curing
Lay pulled onions out in a single layer somewhere warm, shaded, and well-ventilated. Cure for 2–4 weeks until the necks and outer skins are completely dry and papery. This step is not optional if you want them to store. Clip the tops to about an inch above the bulb once fully cured.
Short-term storage
Keep cured onions in a cool, dry, dark spot with good air circulation. A mesh bag, old pantyhose, or a shallow box works well. Sweet onions like Yellow Sweet Spanish keep 2–4 months at best. Eat these first before moving on to storage varieties.
Long-term storage
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Freezing: Chop or slice, freeze flat on a tray, then bag. No blanching needed. Keeps up to 12 months. Texture softens so use in cooked dishes only.
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Dehydrating: Slice thin and dehydrate at 145°F until completely crisp. Makes excellent onion flakes or powder. Keeps 12 months airtight.
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Refrigerator pickling: Slice thin, pack into a jar with vinegar, salt, and sugar, and refrigerate. Ready in a few hours and keeps for several weeks.
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Pressure canning: Onions can be pressure canned safely but they turn soft and lose most of their flavor. Not worth it on their own.
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Water bath canning: Not safe for plain onions due to low acidity. Pickled onions in an acidified brine are fine.
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Root cellaring: Cured onions store well at room temperature in a cool dry place. Moisture is the enemy so avoid damp cellars.
What to cook
Raw in salads, on sandwiches, or sliced thin on a burger where the mild sweetness is the whole point. Caramelized low and slow until soft and sweet. Added to soups, stews, and stir fries. French onion soup. The answer to that question is always Yellow Sweet Spanish.
Seed Storage & Saving
| Variety |
Yellow Sweet Spanish Onion |
| Type |
Open-Pollinated |
| Seeds per packet |
~150 seeds |
Storing unused seeds: Keep somewhere cool, dark, and dry. Onion seed loses viability fast. Buy fresh seed every season for reliable germination rates.
Seed saving: Onions are insect-pollinated and will cross freely with other onion varieties nearby. Isolate by at least a quarter mile for reliable purity, or grow only one variety at a time. Onions are biennial, meaning they set seed in their second year. After harvest, select the best bulbs and store them through winter, then replant in spring. Let them bolt and flower. Once the seed heads are dry and the black seeds are visible, cut the stalks, bring inside to finish drying, then shake or rub the seeds out. Store in a cool, dark place.
