Left Continue shopping
Your Order

You have no items in your cart

You might like
FREE Shipping on orders $20 or more!

How to Grow Onions in Colorado

How to Grow Onions in Colorado

Jeena Lugo Jeena Lugo
3 minute read

When it comes to how to grow onions in Colorado, it's crucial to choose the right onion varieties. Long-day varieties, such as Walla Walla, Copra, and Candy, are well-suited for Colorado's growing conditions. These varieties require 14 to 16 hours of daylight to form bulbs, which is ideal for Colorado's long summer days.

Onion seeds can be sown directly into the garden in early spring. Make sure to plant the seeds 1/4 to 1/2 inches deep and keep the soil moist until the seeds germinate. Once the seedlings are a few inches tall, thin them to 4 to 6 inches apart. This spacing allows the onions to grow and form bulbs without overcrowding each other.

If you want to speed up the onion growing process, you can plant onion sets instead of seeds. Onion sets are small bulbs that are about the size of a marble. They are easy to plant and take less time to mature than growing onions from seed. Plant onion sets in early spring, 1 to 2 inches deep and 4 to 6 inches apart.

Onion Seed Assortment | 8 Variety Pack

Onion Seed Assortment | 8 Variety Pack


Onion Seeds For Planting -  8 Long and Short Day Varieties Yellow, Red, White, Sweet and Green Onions for Summer, Fall, Onion Seed By Gardeners Basics This 8-variety Onion Seed Assortment helps you sow a garden of alliums. It includes… read more

Onions need full sun to grow, so make sure to choose a spot in your garden that gets at least six hours of direct sunlight per day. The soil should be well-drained, loose, and rich in organic material. You can amend the soil with compost or aged manure to improve its nutrient content.

Onions need consistent moisture to grow, but overwatering can cause the bulbs to rot. Once the onions start to form bulbs, it's essential to stop watering them. This drying-out process will help the onions mature and form solid bulbs. If the weather is dry, you may need to water the onions occasionally to keep the soil moist.

The bulbing process is crucial to growing onions in Colorado. Onions will start to form bulbs once they reach a certain size and daylight hours increase. To encourage bulb formation, gently bend the onion tops over when they are about halfway matured. This bending process redirects the plant's energy towards forming bulbs instead of growing foliage.

Green onions, also known as scallions, are a popular choice for home gardeners. Green onions are harvested before the bulb has a chance to form, and the tops are cut when they are around 6 inches tall. Green onions can be planted closer together than onions that are grown for bulbs, usually 2 inches apart.

In conclusion, growing onions in Colorado is possible with the right techniques and care. Choose long day onion varieties, plant onion seeds or sets in early spring, and provide full sun and consistent moisture. Stop watering the onions once they start to form bulbs and encourage bulb formation by bending the onion tops over. You can also grow green onions for a quick and easy harvest. With a little patience and effort, you can enjoy fresh and flavorful onions from your garden in Colorado.


« Back to Blog