How to Plant Onions – A Step by Step Guide

In this article we are going to walk through the steps I use to successfully plant onions in my fall or winter garden. Onions are pretty easy to grow and a staple in our kitchen year round. We are planting our onions in October and November.

We had our first dip below freezing in early November in Zone 8b. Make sure to check your zone for the right planting time. Special Note: USDA Plant Hardiness Zones were updated in November of 2023, check for any changes at the link above.

Onion sets (bulbs) a a white granite counter. Purple bulbs are in the top left corner, white onion bulbs are on the right, with one stray purple bulb at the bottom. Yellow onion bulbs are in the bottom left corner.

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Choosing Your Onions – Sets versus Seeds

Onions are truly biennial plants. If you plant seeds you will get small bulbs the first year. The second year will produce onions like those you find in the grocery store. We plant onion sets in our garden, as sets are the easiest way to grow onions.

However, sets come in limited varieties. So, if you want a wider range of varieties you will need to use seeds.

Materials/Tools to Plant Onion Sets

How to Plant Onion Sets

Time needed: 20 minutes

How to Plant Onions

  1. Make a trench in the soil

    Use your trowel or shovel to make a trench in your prepared soil or bed. Place the onion bulbs in the trench at six inch intervals. I like to use a tape measure to make sure I have them spaced properly.Onion bulbs spaced in the garden bed in. a row.

  2. Use the drill and auger bit to make the holes

    You can use a hand shovel to do this step. However, I like to use the drill and augur to loosen up the soil around where the bulb will be growing. This address any issues with the soil being compacted and gives the bulbs plenty of room to grow.A green auger bit attached to a drill digging a hole in the garden soil.

  3. Place the onions in the holes

    Place the onions in the holes with the root side down and the pointy side up. They will still grow if you mistakenly plant upside down, but give them the best start you can. Onion bulbs in the holes we dug with the auger.

  4. Cover the bulbs with soil and water in

    Cover the onions with soil and water them in to remove any air pockets.  A red handled garden shovel next to the row of the onions covered with soil

Planting Onions – What to Expect Next

Your onions may sprout or form shoots above the ground prior to a hard freeze in your area. Don’t worry, this is normal and actually good. The plants will go dormant and start to regrow in the spring.

It’s important to keep the area weed free (or in my yard, leaf and acorn free) this will help prevent pests from overwintering and becoming a bigger problem in the spring. We are busy raking leaves and will be adding a thick layer of leaf mulch.

Here is a picture of the onions we planted back at the end of October. Approximately, 7 weeks after planting.

Onion bulbs in a garden bed in mid December. Oak leaves are scattered in the garden bed.

Conclusion – Planting Onions

We hope you found this article on how to plant garlic helpful and that you will check back for updates as we will be updating this page as our plants grow and when we are ready for harvest.

Onion Plant Care Reference Card

Onion Plant Care Reference Card
Common NameOnion
Botanical NameAllium cepa
FamilyAmaryllidaceae
Plant TypeBiennial, commonly grown as an annual
SizeTypically 6 to 18 inches tall and wide
Sun ExposureFull sun
Soil TypeWell-drained, rich in organic matter
Soil pHSlightly acidic to neutral (pH 6.0 to 7.0)
Bloom TimeFlowers in the second year; mainly grown for bulbs
Hardiness Zones3 to 9 (grown annually)
Native AreaAsia
ToxicityNon-toxic to humans; toxic to pets, especially cats and dogs

Comprehensive Guide to Onion Plant Care

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