When to Plant Onion Sets: Spring, Fall, and Climate Guide

Planting onion sets at the right time helps them establish strong roots and produce the kind of harvest you want. For outdoor growing, onion sets can be planted from early spring through early summer, depending on your growing zone and whether you want full-size bulbs or quick salad onions.

Onion sets Fresh Garden Living

When to Plant Onion Sets Outdoors

For full-size onions, plant sets as soon as the soil can be worked in early spring. In many areas, this is 2–4 weeks before the last expected spring frost. Onion sets tolerate light frost, but the soil should not be frozen, waterlogged, or too wet to work.

In cooler zones or for salad onions and successive crops, planting can continue into late spring and early summer. Plant a new row about every 2 weeks for a steady supply of fresh green onions and small salad onions.

Succession Planting for Salad Onions

Onion sets are especially useful for succession planting. Plant a small batch every 2 weeks, adjusting the schedule to your climate and the amount you use. Harvest them young for mild salad onions, or allow them more time to size up.

Growing Salad Onions Indoors

Onion sets can also be planted indoors year-round to produce fresh salad onions. Use a container with drainage and a quality potting mix, place it in a bright location, and keep the soil lightly and consistently moist. Harvest green tops as needed, leaving enough growth for the plant to continue producing.

planting Fresh Garden Living onion sets in container

When to Plant Onion Sets in Fall

In mild-winter areas, plant onion sets about 4–6 weeks before the first hard frost. This gives the sets time to root before cold weather arrives. Fall-planted onions may overwinter and produce an earlier harvest the following year.

Choose cold-hardy varieties and protect young plants with a light mulch after the ground begins to cool. Fall planting is less reliable in areas with severe winters unless the variety is specifically suited to overwintering.

Planting by Climate and Day Length

  • Southern areas: Short-day onions generally perform best, and fall planting may be possible.
  • Northern areas: Long-day onions are usually a better fit, with spring planting being the most common approach.
  • Middle latitudes: Intermediate-day varieties can be a good choice, depending on the specific variety and local conditions.

If you are unsure, check the variety’s recommended growing region and compare it with your local conditions.

onion sets planted in garden

Quick Planting Checklist

  • Choose a sunny, well-drained location outdoors, or a container with drainage indoors.
  • Plant the pointed end up and the root end down.
  • Set bulbs about ½–1 inch deep, with the tip at or just above the soil surface.
  • Space sets 4–6 inches apart for full-size bulbs, or closer for salad onions.
  • Water after planting, then keep soil consistently moist without waterlogging.

For complete planting instructions, see our guide to growing onions from sets. Ready to plant? Shop onion sets for your garden.
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