When to plant onions

Timing

Onions are grown from seed, sets, or transplants; plant seed for bulb onions in the early fall; onion sets can be planted in fall or early spring; onions grown from transplants should be planted in the early spring. Timing on their sheet — not a BioArva calendar.

Sets

Their sheet distinguishes sets over one inch. Set-size context on their sheet — not a BioArva standard or diagnosis.

Timing

Onions grow best during cool weather and are usually planted in the fall in South Carolina for late spring harvest; onion plants can also be planted in early spring for summer harvest. Timing on their sheet — not a BioArva calendar.

Timing

Their sheet lists onion-set windows of Feb 15 to Mar 30 (Piedmont spring) and Sept 15 to Oct 15 (Piedmont fall); Coastal spring Feb 1 to Mar 15 and fall Sept 15 to Nov 15. Timing on their sheet — not a BioArva calendar.

Timing

Plant onion seed directly in the garden in fall in Coastal and Central areas; seed is not a recommended method for growing onions in the Piedmont area of South Carolina. Timing on their sheet — not a BioArva how-to.

Timing

Set out transplants from late December through February; plants should be about 6 inches high and about half the thickness of a lead pencil at transplanting. Timing/size on their sheet — not a BioArva how-to.

Depth

Sets should be planted 1½ inches deep and seeds ½ inch deep. Planting-stock depth on their sheet — not a BioArva how-to.

Depth

Set plants with the bottom of the plant about 1 to 1½ inches below the surface of the soil. Transplant depth on their sheet — not a BioArva how-to.

Depth

Sow eight to 12 seeds per foot of row ½ to ¾ inches deep. Seed-depth on their sheet — not a BioArva how-to.

Timing

Their sheet lists onion-plant windows of Sept 15 to Oct 15 (Piedmont) and Oct 1 to Nov 15 (Coastal). Timing on their sheet — not a BioArva calendar.

Timing

Their sheet lists onion-seed windows of Sept 15 to Oct 30 in Coastal areas. Timing on their sheet — not a BioArva calendar.

Day-length

Short day varieties set bulbs with about 12 hours of daylight and are suitable for growing throughout South Carolina; long day onions cannot be successfully grown in the South. Day-length on their sheet — not a BioArva climate zone.

Limit

South Carolina HGIC 1314 only. Windows are not a national calendar.

Timing

Their sheet lists planting onions in early spring once the garden can be cultivated, and notes cold exposure in the context of seed-stalk development. Timing context on their sheet—not a BioArva calendar or diagnosis.

Timing

Their sheet lists spring planting for onion sets. Timing context on their sheet—not a BioArva how-to.

Start

Either buy bunches of onion transplants or start your own by sowing seeds indoors about 8 weeks prior to planting. Transplant timing on their sheet — not a BioArva how-to.

Hardiness

Onions are hardy (can withstand heavy spring frosts). Hardiness on their sheet — not a BioArva climate zone.

Depth

Sets are planted with the pointed end up and covered with 1 inch of soil. Planting-stock note on their sheet — not a BioArva how-to.

Depth

Sow seed ¼ inch to a ½ inch deep and cover lightly with fine soil. Seed-depth on their sheet — not a BioArva how-to.

Day-length

If the seed catalog lists the variety as long day, it sets bulbs when it receives 15–16 hours of daylight and is adapted to Northern summers; short-day varieties set bulbs with about 12 hours of daylight and are used in the deep South for winter production; there are also intermediate cultivars. Day-length on their sheet — not a BioArva climate zone.

Limit

Maryland onion sheet only.

Timing

Onions can be planted as soon as the garden can be tilled in the spring. Timing on their sheet — not a BioArva calendar.

Timing

Onions can be planted as soon as the garden can be tilled in the spring, usually late March or early April in prime regions for producing onions. Timing on their sheet — not a BioArva calendar.

Depth

To produce dry onions, plant the smaller sets 1 inch deep. Set-depth on their sheet — not a BioArva how-to.

Day-length

Most common varieties fall into long-day (for northern latitudes) and short-day (for southern latitudes); onion varieties grown in the South are not adaptable to the North and vice versa. Day-length on their sheet — not a BioArva climate zone.

Limit

Illinois onion sheet only.

Start

You can grow onions from seed, transplants or small bulbs called sets. Starting-stock note on their sheet — not a ranking.

Timing

Direct seed as soon as the soil is workable in the spring. Timing on their sheet — not a BioArva calendar.

Timing

Onion transplants can tolerate light frosts, and you can plant them when temperatures reach 50°F. Timing on their sheet — not a BioArva calendar.

Start

You can raise your own transplants by starting seed indoors 10 to 12 weeks before planting outside. Indoor-start interval on their sheet — not a BioArva how-to.

Depth

Sow seeds in a 2-inch wide band, 1/4 to 1/2 inch deep, in rows 12 to 18 inches apart. Seed-depth on their sheet — not a BioArva how-to.

Day-length

Storage onions grown in Minnesota generally are long-day types that require 14 or more hours of daylight to form bulbs. Day-length on their sheet — not a BioArva climate zone.

Day-length

Their sheet lists sweet or mild onions as short-day types in Minnesota. Day-length on their sheet — not a ranking or size claim.

Limit

Minnesota onion sheet only.

Timing

Plant onion seeds ¼–½ inch deep in late March or early April. Timing on their sheet — not a BioArva calendar.

Timing

Their sheet lists planting onion seeds in mid to late August for overwintering, with mulch late in the year for overwintered special varieties. Timing on their sheet — not a BioArva calendar or winter-protection promise.

Timing

Their sheet lists April planting for transplants or sets. Timing on their sheet — not a BioArva calendar.

Start

Transplants require about 8 weeks of grow time before planting in the garden. Indoor-start interval on their sheet — not a BioArva how-to.

Day-length

Their sheet lists onion bulbing under long days and hot weather, and notes late-spring planting in the context of leaf growth versus bulb formation. Timing context on their sheet — not a BioArva diagnosis.

Limit

Utah onion sheet only. March–April is Utah, not a national month.