Onion

What you'll need:

Onion seeds, sets (small bulbs), or transplants (choose what’s easiest for you—sets are great for beginners!)

A sunny spot in your garden or a large pot (at least 10 inches deep)

Good quality soil that drains well (onions don’t like soggy feet)

Compost or general-purpose fertilizer to give the soil a nutrient boost

When to start:

Onions love cool weather when they’re growing their green tops and warmer weather when they’re forming bulbs. You can start planting them in early spring if you live in a cooler climate, or in fall if you're in a warmer area where winters are mild.

Choosing the right type of onion:

There are three main types of onions:

• Short-day onions: Best for southern regions with mild winters.
• Long-day onions: Ideal for northern areas with longer summer days.
• Day-neutral onions: Work well almost anywhere.

Check your local garden center for varieties suited to your region.

Preparing the soil:

Onions aren’t too picky, but they do best in loose, well-draining soil. If your soil is heavy or clay-like, mix in some compost or sand to loosen it up. Before planting, sprinkle some compost or a light dose of fertilizer over the soil and mix it in gently.

If using onion sets:

1. Dig small holes about 1 inch deep and space them about 4-6 inches apart (this gives each onion room to grow).
2. Place the onion set in the hole with the pointy end facing up.
3. Cover the bulb with soil and gently pat it down.
4. Water lightly after planting.

If using seeds:

1. Sow seeds about ¼ inch deep in rows, spacing each seed about an inch apart.
2. Once the seedlings sprout and grow to about 6 inches tall, thin them out so there’s 4-6 inches between each plant.
3. Keep the soil moist but not waterlogged while they’re germinating.

If using transplants:

1. Dig holes deep enough to cover the white part of the transplant (the green leaves should stick out).
2. Space them 4-6 inches apart.
3. Gently firm the soil around the base of the plant and water well.

Tip: Onions don’t like competition, so keep weeds away by gently pulling them as soon as you see them!

Watering:

Onions need consistent moisture to grow big bulbs, but too much water can cause them to rot. Aim to water them once or twice a week, depending on how dry the soil feels. The key is to keep the soil moist but not soggy.

Feeding:

Onions aren’t heavy feeders, but they appreciate a little extra nutrition. About a month after planting, sprinkle some balanced fertilizer around the base of the plants and water it in. You can repeat this every few weeks, but don’t overdo it—too much nitrogen will make the leaves grow big at the expense of the bulbs.

Sunlight:

Onions love sunlight! Make sure they get at least 6 hours of direct sun every day. If you’re growing them in pots, place them in the sunniest spot you have.

Weed control:

Keep the area around your onions weed-free. Weeds steal nutrients and water from your onions, which can slow their growth. Be careful when weeding—onion roots are shallow, so avoid disturbing them too much.

Mulching:

Once the onions are established, you can add a light layer of mulch (like straw or grass clippings) around them. This helps retain moisture, keeps the soil temperature even, and reduces weed growth.

When to harvest:

You’ll know your onions are ready to harvest when the tops start to turn yellow and fall over. This usually happens a few months after planting, depending on the variety. Once most of the tops have fallen over, it’s time to pull them up.

How to harvest:

1. Carefully dig around the onion to loosen the soil.
2. Gently pull the onion out by the base of the leaves.
3. Shake off excess dirt but don’t wash them yet—that comes later.

Curing onions:

After harvesting, onions need to “cure” to develop that nice papery skin that helps them store longer. Lay them out in a warm, dry, and well-ventilated area for about 1-2 weeks. Avoid stacking them on top of each other; spread them out so air can circulate around each bulb.

Once cured, trim the tops and roots with scissors or pruners, leaving about an inch of stem above the bulb.

Storage:

Store your cured onions in a cool, dry, and dark place. A basement or pantry works well. Properly cured onions can last for several months!

Tip: If any onions feel soft or have thick necks, use those first—they won’t store as long.

Q: Why are my onion bulbs so small?

A: Small bulbs could mean overcrowding, inconsistent watering, or not enough nutrients. Make sure you’ve spaced them properly and are watering regularly. Also, check that your soil has enough nutrients—adding compost or fertilizer can help.

Q: Can I grow onions in containers?

A: Absolutely! Just make sure the container is deep enough (at least 10 inches) and has good drainage. Space the onions about 4-6 inches apart, just like you would in the ground.

Q: My onion tops are flowering—what does that mean?

A: If the onion starts to flower, it means it’s “bolting,” which happens when the plant is stressed (often due to temperature changes). Once it bolts, the bulb stops growing. You can still eat it, but it won’t store well, so use it soon.

Q: Why are my onions rotting in the ground?

A: Overwatering or poor drainage can cause onions to rot. Make sure the soil isn’t staying too wet. If you live in a rainy area, raised beds or containers might work better.

Q: How do I know if my onions are short-day or long-day varieties?

A: Check the seed packet or ask at the garden center. Short-day onions are better for southern climates with shorter daylight hours, while long-day onions thrive in northern areas with longer summer days.