Getting your timing right is the first step to a great onion harvest. Knowing exactly when to plant onions in central Florida makes all the difference between sweet, juicy bulbs and disappointing results.
Our unique climate here offers two distinct planting windows. This guide gives you the clear schedule and simple steps you need for success.
When To Plant Onions In Central Florida
Central Florida gardeners have a big advantage: two main planting seasons. The primary season is in the fall, for larger bulb onions. A secondary season happens in late winter for green onions or smaller bulbs.
The most critical factor is day length. Onions are photoperiodic, meaning they bulb in response to how long the day is. For us, you need to choose “short-day” onion varieties. These start forming bulbs when daylight lasts 10-12 hours, which matches our winter and spring.
The Fall Planting Window (Main Crop)
This is your best chance for big, storage-quality onions. The goal is to get plants established in the cool fall weather so they can grow strong roots and leaves. Then, as days lengthen in late winter and spring, they switch energy to forming the bulb.
- Best Dates: Plant onion sets, transplants, or seeds from October through December.
- Ideal Target: Mid-October to mid-November is often perfect. This gives plants plenty of time to grow before bulbing begins.
- Why Then? The cooler temperatures reduce pest pressure and allow for steady growth without the stress of summer heat.
The Late Winter Planting Window (Second Chance)
If you missed the fall window, you can still plant in late winter. The results will be different, but still useful for any kitchen.
- Best Dates: Plant in January or early February at the very latest.
- What to Expect: Onions planted this late won’t have as much time to grow before bulbing starts. You’ll likely harvest smaller bulbs or excellent green onions for fresh use.
Choosing Your Onion Type: Sets, Transplants, or Seeds?
You have three options for starting your onions. Each has its pros and cons for timing and ease.
- Seeds: These offer the most variety but take the longest. Start seeds indoors in September or early October. Transplant the seedlings into the garden in November. This method requires the most planning.
- Transplants (Starts): These are small, live onion plants sold in bunches. They are the most popular and reliable choice for most gardeners. Plant these directly in the garden during the main fall window (Oct-Dec).
- Sets: These are small, dried onion bulbs from the previous year. They are easy to plant but can bolt (flower) more easily in our climate. If using sets, plant them in the fall window. Choose the smallest sets you can find, as larger ones are more prone to bolting.
Step-by-Step Planting Guide
Follow these steps to get your onions off to a strong start.
1. Select the Right Varieties
Stick with proven short-day varieties. Some excellent choices for central Florida include:
- Yellow Granex (the famous “Vidalia” type)
- Texas Super Sweet
- Red Burgundy
- White Bermuda
- Southern Belle Red
2. Prepare Your Garden Bed
Onions need loose, well-draining soil and plenty of nutrients.
- Choose a spot that gets full sun (at least 6-8 hours).
- Loosen the soil to a depth of about 8 inches.
- Mix in 2-3 inches of compost or well-rotted manure. Onions are heavy feeders.
- Add a balanced, slow-release fertilizer according to package directions when you bed is prepared.
3. Planting Correctly
Proper spacing and depth are crucial.
- Create rows spaced about 12-18 inches apart.
- For transplants and sets: Plant each one just deep enough so the base is covered, with the top point peeking out. Space them 4-6 inches apart in the row.
- For seeds sown directly: Plant seeds about 1/2 inch deep and thin seedlings later to the 4-6 inch spacing.
- Water the bed thoroughly immediately after planting to settle the soil.
Caring for Your Onion Crop
Consistent care through the growing season leads to a much better harvest.
Watering
Onions have shallow roots and need consistent moisture. Water deeply when the top inch of soil feels dry. Drip irrigation or soaker hoses are ideal to keep foliage dry and prevent disease. Reduce watering as the bulbs mature and the tops begin to yellow and fall over.
Fertilizing
Feed your onions every 3-4 weeks with a nitrogen-rich fertilizer, like a fish emulsion or a balanced vegetable food. Stop fertilizing once the bulbs begin to swell noticeably (you’ll see the soil crack around them).
Weeding
Weeds compete heavily with shallow-rooted onions. Hand-pull weeds carefully to avoid disturbing the onion roots. A thin layer of straw or pine straw mulch can help suppress weeds and retain soil moisture, which is a big help.
Common Pests and Problems
Stay vigilant for these few issues.
- Thrips: Tiny insects that cause silvery streaks on leaves. Use insecticidal soap or a strong spray of water to control them.
- Onion Maggots: Less common but damaging. Crop rotation is the best prevention—don’t plant onions in the same spot year after year.
- Bolting: This is when an onion sends up a flower stalk. The bulb stops growing and won’t store well. Bolting is often triggered by temperature fluctuations or planting the wrong type (like a long-day variety). If you see a stalk form, harvest and use that onion right away.
Harvesting and Curing for Storage
Knowing when and how to harvest ensures your onions last.
- Watch for Signs: In late spring, the onion tops will naturally turn yellow, brown, and flop over.
- Stop Watering: Once most tops have fallen, stop watering for about a week.
- Harvest: On a dry, sunny day, gently lift the bulbs with a garden fork. Brush off excess soil, but don’t wash them.
- Cure: Lay the onions in a single layer in a warm, dry, airy place out of direct sun (like a garage or covered porch) for 2-3 weeks. The necks will dry and the outer skins will become papery.
- Store: After curing, trim the roots and cut the dried tops down to about an inch. Store in a cool, dry, dark place in a mesh bag or basket.
FAQ: Onion Planting in Central Florida
Can I plant onions from the grocery store?
It’s not recommended. Those are often long-day varieties unsuited for our climate and may have been treated to prevent sprouting. You’ll have much better luck with certified short-day seeds, sets, or transplants.
What if I planted my onions too late?
You’ll likely get smaller bulbs or excellent green onions. Simply harvest them as needed for fresh eating. They probably won’t cure and store well for long term.
How long do onions take to grow?
From transplant in the fall, most short-day onions will be ready for harvest in March, April, or May. The exact timing depends on your planting date and the variety you chose.
Why are my onions so small?
Small bulbs can result from planting too late, using the wrong (long-day) variety, overcrowding, inconsistent watering, or insufficient fertilizer during the leaf-growth stage.
Can I grow onions in containers?
Absolutely. Choose a container at least 10 inches deep. Ensure it has excellent drainage and use a high-quality potting mix. Follow the same spacing and care guidelines. Container onions may need water more frequently.
Sticking to the fall planting schedule is your biggest key to success. With the right short-day varieties and consistent care, you can enjoy a homegrown onion harvest that is both rewarding and delicious. Remember, gardening is a learning process, and even a less-than-perfect harvest teaches you something for next season.