The Ultimate Guide to Knowing When to Plant Garlic and Onions

Garlic and onions are two of the most popular allium crops grown in home vegetable gardens. They add tremendous flavor to meals and offer great health benefits too. But timing is everything when it comes to planting garlic and onions. Get it right, and you’ll be rewarded with large, flavorful bulbs. Miss the ideal window, and yields can suffer. So when exactly is the optimal time to plant garlic and onions? Read on for a complete guide.

Spring or Fall – Which is Best?

There are two main seasons during which garlic and onions can be planted:

Spring Planting

• Plant bulbs or sets April – early May after danger of frost has passed.

• Sow onion seeds indoors 6-8 weeks before last spring frost,

• Spring planting is preferred in hot climates like the South.

Fall Planting

• Plant garlic and onion sets September – November, about 4-6 weeks before first fall frost.

• Allows crops to establish roots before winter dormancy.

• Fall planting produces larger bulbs and enhanced flavor.

• Recommended for northern and cooler climates.

While specific timing varies by growing zone and climate, most gardeners have success with either season. However, there are some distinct advantages to fall planting:

Benefits of Fall Planting

• Larger bulbs form with fall planting. The extra growing time before winter dormancy boosts size.

• More robust, developed root systems give plants a head start in spring.

• Extended exposure to cold winter temps enhances flavor profile.

• Bulbs cured in ground often store better than spring harvested bulbs.

• Jump start on growth means earlier maturity and harvest next summer.

• Avoid issues with bolting, premature sprouting, and disease in hot summers.

So in most regions, planting garlic and onions in fall is ideal. But spring planting can still produce a good crop if done properly.

When to Plant Garlic

• Best planted 6-8 weeks before first expected fall frost for winter growth.

• In spring, plant garlic as soon as soil can be worked, usually February – April.

• Optimal soil temperature for planting is about 60°F.

• Start soaking garlic cloves 2-3 days before planting.

• Plant individual cloves 2-3 inches deep and 4-6 inches apart.

• Place cloves root end down and tip facing up.

When to Plant Onions

Onion Seeds

• Start seeds indoors 6-8 weeks before your last average spring frost.

• Move outdoors when around 2″ tall and after hardening off seedlings.

• Or direct sow in spring as soon as soil can be worked and is above 50°F.

Onion Sets

• Plant sets in spring once threat of frost has passed.

• For fall, plant 4-6 weeks before first expected autumn frost.

• Space onion sets 1-2 inches deep and 2-4 inches apart.

Tips for Planting Success

• Loosen soil and mix in compost or fertilizer 2-3 weeks before planting.

• Test soil pH – onions prefer slightly acidic around 6.0-6.5. Garlic likes more neutral pH of 6.5-7.0.

• Soak bulbs overnight before planting to boost sprouting.

• Plant in rows or blocks for easier maintenance.

• Cover planted rows with 2-4 inches of mulch to retain moisture and discourage weeds.

• Irrigate when top inch of soil is dry. Avoid overwatering.

• Monitor for pests like onion maggots and apply organic treatments promptly.

Knowing the optimal time to plant is the first step to growing a thriving crop of garlic and onions. While spring planting is an option in some regions, most gardeners find better results planting bulbs and sets in fall. Pay close attention to your specific climate and seasonal weather patterns. With the right timing and care, you’ll be harvesting an abundant supply of large, flavorful garlic and onions.