How to: Square Foot Gardening Onions

Square foot gardening is a method where crops are planted in squares in a garden. By interplanting crops and growing your plants tight together, you can maximize your production and decrease pest problems. In this article we’ll explore the specifics of square foot gardening onions. Onions are excellent at repelling certain pests and are one of my favorite vegetables to include in a square foot garden.

If you are new to square foot gardening, I suggest you start here in our complete guide or you can learn more in our mini-course.

Contents

Spacing for Square Foot Gardening Onions

For each square foot in the garden, you can plant 9-16 onions. I like to plant them in a grid in early spring and put in several squares of onions throughout each square foot garden. This spreads out the benefits of the onions and since they are often some of the first plants to grow, I like having different plants coming up in the garden.

Brief Overview of Square Foot Gardening

Square Foot Gardening (SFG) is a method that maximizes space by dividing garden beds into small, manageable squares, making it perfect for growing a variety of crops in a limited area. It’s known for its space efficiency, ease of maintenance, and ability to produce high yields with less effort. Onions are an ideal choice for SFG because they’re compact, easy to grow, and highly versatile in the kitchen, making them a staple in any home garden.

Importance of Onions in the Garden

Onions are a great crop for a square foot garden. Beyond their use in the kitchen, they also help to repel pests and can improve the health of neighboring plants. Their ability to deter harmful insects makes them an beneficial crop for any gardener looking to maintain a healthy and productive garden.

Selecting the Right Onion Varieties

Bulb Onions vs. Green Onions (Scallions)

When it comes to growing onions in your square foot garden, it’s important to decide whether you want to grow bulb onions or green onions, also known as scallions. Bulb onions are the classic, round onions that develop a large bulb at the base and are harvested when fully mature. They come in different colors—yellow, red, and white—and are a kitchen staple for cooking and preserving. These onions require a longer growing period and are usually planted for a specific harvest season.

On the other hand, green onions (scallions) are harvested while the bulbs are still small and the green tops are tender. Scallions grow quickly and are perfect for continuous harvesting throughout the growing season. They’re ideal for gardeners who want a quick-growing crop with a mild onion flavor, perfect for salads, garnishes, and light cooking. Scallions also take up very little space and can be planted densely, making them an excellent choice for square foot gardening.

I’ve used both in the square foot garden, but I prefer the bulb onion.

Day-Length Varieties: Short-Day, Intermediate-Day, and Long-Day Onions

Onions are classified into three main types based on the amount of daylight they need to form bulbs: short-day, intermediate-day, and long-day onions. Choosing the right type is crucial for a successful harvest.

Short-Day Onions: These varieties require about 10-12 hours of daylight to start forming bulbs and are typically grown in regions with mild winters, such as the southern United States. They are planted in the fall or winter and mature by late spring. Some popular short-day varieties include ‘Texas Grano’ and ‘Red Creole’.
Intermediate-Day Onions: These onions need 12-14 hours of daylight and are more versatile, growing well in both southern and northern regions. They are usually planted in early spring and harvested in mid to late summer. ‘Candy’ and ‘Super Star’ are popular intermediate-day varieties known for their sweet flavor and large bulbs.
Long-Day Onions: Requiring 14-16 hours of daylight, long-day onions are best suited for northern regions where summer days are longer. They are planted in early spring and harvested in late summer to early fall. Varieties like ‘Walla Walla’ and ‘Yellow Sweet Spanish’ are well-known long-day onions that produce large, flavorful bulbs.

Recommended Varieties for Your Region

Selecting the right onion variety for your region ensures optimal growth and a bountiful harvest.

Southern Regions: If you’re gardening in the South, opt for short-day varieties like ‘Vidalia’, ‘Texas 1015’, or ‘Red Creole’. These onions thrive in the milder winter climates and mature quickly before the summer heat sets in.
Mid-Region: Gardeners in the middle zones can benefit from intermediate-day onions like ‘Candy’, ‘Red Burgermaster’, or ‘Sweet Vidalia’. These varieties can handle the varying day lengths and temperatures of these regions.
Northern Regions: In the North, where daylight hours are longer in summer, long-day varieties such as ‘Walla Walla’, ‘Yellow Sweet Spanish’, or ‘Copra’ are ideal. These onions can take advantage of the extended daylight to form large, robust bulbs.

By understanding the differences between bulb onions and green onions, recognizing the importance of day-length sensitivity, and choosing the right variety for your region, you can ensure a successful onion crop in your square foot garden.

Top Tips for Growing Onions in a Square Foot Garden

Choose the Right Variety: Select short-day, intermediate-day, or long-day onions based on your region’s climate and daylight hours.
Proper Spacing: Plant 9-16 onions per square foot to ensure each bulb has enough space to grow.
Well-Drained Soil: Onions thrive in loose, well-drained soil rich in organic matter. Amend with compost for best results.
Sunlight: Ensure your onions receive at least 6-8 hours of direct sunlight daily for optimal growth.
Consistent Watering: Keep the soil consistently moist but not waterlogged, especially during the bulb formation stage.
Mulch for Weed Control: Apply mulch to help retain moisture and prevent weeds, which can compete with onions for nutrients.
Fertilize Regularly: Use a nitrogen-rich fertilizer every few weeks during the growing season to encourage strong growth.
Companion Planting: Pair onions with beneficial plants like carrots and lettuce, and avoid planting near beans or peas.
Pest Control: Keep an eye out for common pests like onion maggots or thrips and use natural methods to manage infestations.
Harvest at the Right Time: Harvest when the tops begin to yellow and fall over, and cure onions properly for long-term storage.