Knowing the right time to plant onions in North Florida is the single most important factor for a successful harvest. Get the timing wrong, and your bulbs might never form properly. This guide gives you the optimal timing for planting, along with clear steps to grow big, sweet, or pungent onions in your garden.
Onions are a cool-season crop, which means they prefer to grow during the milder parts of the year. In North Florida, our unique climate—with its mild winters and early, hot springs—creates a specific planting window. Missing this window is the most common mistake gardeners make here.
When To Plant Onions In North Florida – Optimal Timing For Planting
The golden rule for North Florida is to plant onion sets, transplants, or seeds in the fall. Your target planting period is from October through December. Planting in early fall allows the onions to establish strong roots and leafy top growth during the cool winter months. When the longer, warmer days of spring arrive, the plants are ready to switch their energy into forming the bulb underground.
For the most precise timing, use this simple monthly guide:
* October – Early November: This is the ideal window for planting onion transplants (small seedlings) or sets (tiny bulbs). The soil is still warm from summer, which encourages quick root development.
* November – December: You can continue planting transplants and sets. This is also the best time to direct-sow onion seeds if you started a bit late; seeds need a longer growing season, so getting them in the ground by early December is crucial.
* January – February: This is considered late planting. Only the fastest-maturing, short-day varieties have a chance to size up if planted now. It’s generally not recommended for beginners.
* March and beyond: Spring planting is too late for bulbing onions in our region. The plants will encounter hot weather just as they should be bulbing, leading to small onions or premature bolting (flowering).
Choosing the Right Onion Type for Our Climate
Not all onions are created equal, and choosing the wrong type is a recipe for disappointment. Onions are categorized by their response to day length—how many hours of sunlight they need to trigger bulb formation.
North Florida gardeners must plant short-day onions. These varieties begin forming bulbs when they receive 10-12 hours of daylight. Our spring days provide this perfect length. If you plant a long-day onion (needing 14-16 hours of daylight), it will never get the signal to form a bulb in our latitude.
Here are some proven, recommended short-day onion varieties for North Florida:
* Yellow Granex: The famous sweet Vidalia-type onion. Mild and sugary.
* Texas Early Grano 1015Y: A reliable, large, yellow onion that stores well.
* Red Burgundy: A beautiful, deep purple onion with a mild flavor, perfect for salads.
* White Granex: Similar to the yellow, but with a white skin and a very sweet taste.
* Southern Belle Red: A newer variety known for its good storage life and uniform shape.
Always check the seed packet or plant tag to confirm it says “Short-Day” onion.
Step-by-Step Planting Guide
Now that you know when and what to plant, let’s get them in the ground correctly.
1. Preparing Your Garden Bed
Onions need loose, well-draining soil and plenty of nutrients. Start by choosing a spot that gets full sun—at least 6-8 hours of direct light. Work the soil to a depth of about 8 inches, breaking up any clumps. Mix in a generous amount of compost or well-rotted manure. Onions are heavy feeders, so also incorporate a balanced, slow-release fertilizer according to package directions. Rake the bed smooth.
2. Planting Transplants, Sets, or Seeds
* Transplants (Recommended): These are small, bare-root onion seedlings you can often find at local nurseries in fall. They give you a head start. Plant them about 1 inch deep, spacing them 4-6 inches apart in rows that are 12-18 inches apart.
* Sets: These are small, dried onion bulbs. They are easy to plant but can be more prone to bolting. Choose sets that are smaller than a dime in diameter; larger sets are more likely to flower. Plant them just deep enough to cover the bulb, with the tip pointing up, using the same spacing as transplants.
* Seeds: Starting from seed gives you the most variety choice but takes the longest. Sow seeds about ¼ inch deep and 1 inch apart. You will need to thin the seedlings later to the proper 4-inch spacing.
Caring for Your Onion Plants
Consistent care through the winter and spring is key to plump bulbs.
Watering and Feeding
Onions have shallow roots, so they need consistent moisture. Water deeply when the top inch of soil feels dry, providing about 1 inch of water per week. Avoid frequent, shallow sprinkling. About 4-6 weeks after planting, side-dress your onions with a nitrogen-rich fertilizer, like blood meal or a granular vegetable fertilizer, to support strong leaf growth. Scratch it lightly into the soil beside the row and water it in.
Weeding and Mulching
Weeds are a major competitor for onions. Hand-pull weeds carefully, as onions have shallow roots that can be easily disturbed. Applying a 2-3 inch layer of organic mulch, like pine straw or chopped leaves, is a great way to supress weeds and retain soil moisture. It also helps keep the soil temperature more even.
Common Problems and Solutions
Even with good timing, you might encounter a few issues.
* Bulbs Not Forming: This is almost always caused by planting the wrong onion type (long-day instead of short-day) or planting too late in the season.
* Bolting (Flowering): If an onion sends up a flower stalk, the bulb stops growing. This is caused by stress from temperature fluctuations, especially a cold snap after warm weather. Once it bolts, you can’t reverse it; just use that onion soon, as it won’t store well.
* Pests: Thrips are tiny insects that can cause silvery streaks on leaves. Spray plants with a strong stream of water or use an insecticidal soap. Onion maggots are less common but can be deterred by crop rotation.
* Diseases: Fungal issues like downy mildew or purple blotch can occur in wet, humid conditions. Ensure good air circulation, avoid overhead watering, and remove any infected plants promptly.
Harvesting and Storing Your Onion Crop
Your onions are ready to harvest when the tops begin to turn yellow and fall over naturally. This usually happens in late April through May in North Florida. When about half the tops have fallen, gently push over the remaining ones to signal the plant to stop growing.
After a week, on a dry, sunny day, carefully lift the bulbs with a garden fork. Let them cure (dry) right in the garden for a few days if weather permits, or move them to a covered, well-ventilated area out of direct rain and sun. Let them cure for 2-4 weeks until the necks are tight and the outer skins are papery.
Once fully cured, trim the roots and cut the tops down to about 1 inch. Store your onions in a cool, dry, dark place with good air circulation, like a mesh bag or a single layer in a crate. Properly cured short-day onions can last for several months.
Frequently Asked Questions (FAQ)
Can I plant onions in the spring in North Florida?
No, spring planting is not successful for bulbing onions. The rapidly increasing heat and day length will cause them to bulb prematurely while the plants are still to small, or they may simply bolt.
What is the difference between onion sets and transplants?
Sets are small, dormant bulbs from the previous year. Transplants are active, growing seedlings started from seed that same season. Many gardeners find transplants more reliable and less prone to bolting than sets in our climate.
How do I know if an onion is a short-day variety?
The seed packet or plant description will always state “short-day.” When in doubt, stick with the recommended varieties listed earlier, such as Granex or Texas Early Grano.
Can I grow onions in containers?
Yes, you can! Choose a container at least 10-12 inches deep and wide. Ensure it has excellent drainage holes and use a high-quality potting mix. Follow the same spacing and care instructions, but be extra vigilant about watering, as containers dry out faster.
Why are my onion leaves turning yellow?
Some yellowing at the neck as harvest approaches is normal. Widespread yellowing earlier in the season could indicate overwatering, a nutrient deficiency (like nitrogen), or a fungal disease. Check your watering habits and inspect the leaves for other signs of pests or spots.
Getting the timing right for planting onions in North Florida makes all the difference. By following this schedule and choosing the correct short-day varieties, you’ll be well on your way to a bountiful harvest of homegrown onions. Remember, the fall planting window is your best friend for this classic garden crop.