By Ada Jones · Updated October 2026 · 6 min read Short answer: Epsom salt (magnesium sulfate) only helps onions if your soil is actually magnesium-deficient, which is uncommon outside sandy or heavily leached soils. It’s not a general bulb-size booster, and online claims that it reliably produces bigger onions aren’t backed by controlled research…
By Ada Jones · Updated October 2026 · 7 min read Short answer: onions bulb based on day length, not temperature or calendar date. Short-day varieties need about 10-12 hours of daylight to start bulbing, intermediate-day need 12-14 hours, and long-day need 14-16 hours. Pick the category that matches your latitude, or the wrong variety…
By Ada Jones · Updated October 2026 · 6 min read Short answer: estimate your harvest date by adding your variety’s “days to maturity” (printed on the seed packet or set label) to your planting date — as a guide, about 60 days from sets, 2–4 months from transplants, and up to 5 months from…
By Ada Jones · Updated October 2026 · 7 min read Short answer: onion seeds germinate slowly (7-14 days under ideal conditions, sometimes 21+ in cool soil) and poor germination is almost always down to old seed, soil that’s too cold or too wet, or planting too deep. Onion seed also loses viability fast —…
By Ada Jones · Updated October 2026 · 8 min read Short answer: plant onions 4-6 weeks before your last spring frost date in most of the US and Canada, or in fall (Sept-Nov) in mild-winter zones 7-10 for an overwintered crop. The exact window depends on your USDA hardiness zone and whether you’re growing…
By Ada Jones · Updated October 2026 · 9 min read Short answer: red onions are milder and best eaten raw or lightly cooked; yellow onions are the all-purpose cooking workhorse with the strongest flavor and longest storage life; white onions are sharp and crisp, common in Mexican and Southwestern cooking; and sweet onions (like…
By Ada Jones · Updated October 2026 · 8 min read Short answer: harvest onions when about half the tops have fallen over on their own, cure them somewhere warm, dry, and airy for 2 to 3 weeks until the necks are fully dry and papery, then store the cured bulbs somewhere cool, dark, and…
By Ada Jones · Updated October 2026 · 8 min read Short answer: the onion pests and diseases that actually cause crop loss for home growers are thrips (tiny sap-sucking insects causing silvery streaks), onion maggots (larvae that tunnel into young bulbs, especially in cool wet spring soil), and the fungal diseases downy mildew, purple…
By Ada Jones · Updated October 2026 · 7 min read Short answer: yellow onion leaves are almost always one of four things: natural die-back as bulbs mature, nitrogen running low mid-season, overwatering/poor drainage, or a fungal disease like downy mildew or purple blotch. Tip yellowing that starts at the oldest (outer) leaves and moves…
Container Growing How to Grow Onions in Pots and Containers You can grow full bulb onions in containers if the pot is deep enough and gets full sun. Sources vary on exact sizing, but the safe range is a container at least 8 to 12 inches deep at minimum, and ideally 12 to 15 inches…
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