Onions
Onions, with their crisp, flavorful bulbs and tall, slender green tops, add a practical and aromatic touch to any garden. Known for their versatility in the kitchen, onions come in a variety of types, including red, yellow, and white, each with its unique flavor profile. Their growth begins with small, green shoots that develop into robust, layered bulbs, making onions a staple in garden beds or containers.
In Florida planting zone 9, onions grow well, particularly during the cooler months. The plants form sturdy bulbs beneath the soil while their tops reach skyward. Watching the bulbs swell and mature underground is a satisfying experience, signaling the success of your gardening efforts.
For those new to gardening, onions are a rewarding choice. They are relatively easy to grow and provide a continuous supply of fresh bulbs that can be used in a wide range of dishes. Whether you enjoy them raw, sautéed, or caramelized, onions bring a flavorful and aromatic element to your meals, making your gardening endeavors both productive and delicious.
I would give onions a 4 out of 5 on how easy they are to grow. They are relatively straightforward to cultivate, making them suitable for both beginners and experienced gardeners.
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Onion Varieties:
Granex (Vidalia)
Description: Granex onions, commonly known as Vidalia onions when grown in specific regions of Georgia, are sweet onions with a mild flavor. They have a slightly flattened shape and a pale yellow skin.
Growing Season: Fall and Winter
USDA Planting Zone: 7–10
Special Notes: Excellent for fresh eating due to their mild flavor. Ideal for salads and sandwiches.
Texas Super Sweet
Description: Texas Super Sweet onions are large, globe-shaped onions with a very sweet flavor. They have a light yellow to white skin and are known for their excellent storage qualities.
Growing Season: Fall and Winter
USDA Planting Zone: 7–10
Special Notes: Suitable for fresh use and storage. They are one of the sweetest onion varieties available.
Red Creole
Description: Red Creole onions are small to medium-sized, globe-shaped onions with a deep red skin. They have a pungent flavor and are excellent for cooking and salads.
Growing Season: Fall and Winter
USDA Planting Zone: 7–10
Special Notes: Good storage qualities and can add color to dishes. They are heat-tolerant and perform well in warm climates.
Yellow Granex
Hybrid
Description: Yellow Granex onions are similar to the Granex (Vidalia) but are specifically bred to thrive in warmer climates. They have a sweet, mild flavor and are slightly flattened in shape.
Growing Season: Fall and Winter
USDA Planting Zone: 7–10
Special Notes: Ideal for fresh eating and cooking. They are not as pungent as other yellow onion varieties.
White Bermuda
Description: White Bermuda onions are large, flat onions with a mild, sweet flavor. They have white skin and are commonly used in salads, sandwiches, and cooking.
Growing Season: Fall and Winter
USDA Planting Zone: 7–10
Special Notes: Excellent for fresh use and relatively easy to grow. They mature quickly compared to other varieties.
Egyptian Walking Onion (Allium × proliferum)
Description: Egyptian Walking Onions, also known as Tree Onions or Topset Onions, are unique perennial onions that produce small clusters of bulbils at the top of their stalks instead of flowers. These bulbils can be planted to grow new onions, hence the name "walking onions," as they can spread and "walk" across the garden over time.
Growing Season: Fall, Winter, and Spring
USDA Planting Zone: 3–9
Special Notes: Flavor: The bulbs have a strong, pungent flavor similar to regular onions. The greens can be used like scallions, and the small top-set bulbs are great for pickling or fresh use. Growth Habit: The plant produces a main bulb underground, which can be harvested like a regular onion, and clusters of small bulbils at the top of the stalk. As stalks fall and bulbils root, new plants form over time. Perennial: Egyptian Walking Onions are perennial and can be left in the ground year-round, producing new growth each season.
Florida Vegetable Planting Guide
This guide provides information on when to start seeds inside, direct seed, and transplant starter plants in the different regions of Florida.
North USDA Planting Zones: 8b–9a
Central USDA Planting Zones: 9b & some of 10a
South USDA Planting Zones: 10a–11b
Visit the U.S. National Arboretum for an Exact USDA Planting Zone Map.
| Bulb Onions | North Florida | Central Florida | South Florida |
|---|---|---|---|
| Start Seeds Inside | Sep–Nov | Oct | Oct |
| Direct Seed | Not recommended | Not recommended | Not recommended |
| Transplant Starter Plants | Mid Sep–Mid Nov | Oct | Oct |
| Bunching Onions | North Florida | Central Florida | South Florida |
|---|---|---|---|
| Start Seeds Inside | Jul–Feb | Jul–Feb | Aug–Feb |
| Direct Seed | Aug–Mar | Aug–Mar | Sep–Mar |
| Transplant Starter Plants | Sep–Mar | Sep–Mar | Oct–Mar |
Planting Guide – Onions
Getting Started – Bulb & Bunching Onions
Bulb Onions – Start Seeds Inside:
Starting onion seeds indoors in the fall allows for controlled conditions, ensuring strong seedlings ready for
transplanting outdoors in the winter.
Bulb Onions – Direct Seed:
Direct seeding bulb onions is not recommended because it can be challenging to achieve consistent
germination and even bulb development in outdoor conditions.
Bulb Onions – Transplant Starter Plants:
Transplanting onion starter plants during the winter helps them establish quickly in the garden, leading to a
productive harvest before hot weather arrives.
Bunching Onions – Start Seeds Inside:
Starting bunching onion seeds indoors allows for controlled conditions and ensures strong seedlings ready for
transplanting outdoors.
Bunching Onions – Direct Seed:
Direct seeding bunching onions during the cooler months ensures rapid establishment and steady growth in mild
temperatures.
Bunching Onions – Transplant Starter Plants:
Transplanting bunching onion starter plants during the cooler months helps them establish quickly and continue
growing without the stress of high temperatures.
Depending on type, onions may be grown from seed, sets, transplants, or division. Bulb onions must be planted in fall in Florida. Green/bunching onions may be grown fall through spring. Plant close and harvest (thin) as needed. Insert sets upright for straight stems, and divide and reset multiplier types every year.
Soil, Sun, Water, Spacing, and Additional Tips
Soil:
Onions prefer well-drained, fertile soil with a pH between 6.0 and 6.8.
Amend the soil with compost or well-rotted manure to improve fertility and structure.
Sun:
Full sun is essential for optimal growth. Ensure onions receive at least 6–8 hours of sunlight daily.
Watering:
Keep the soil consistently moist but not waterlogged. Mulching helps retain soil moisture and regulate soil
temperature, especially during dry or windy conditions.
Spacing:
- Bulb Onions: Plant sets or transplants 4–6 inches apart in rows spaced about 14 inches apart. Proper spacing ensures good air circulation and room for full bulb development.
- Bunching Onions: Plant sets or transplants about 2 inches apart for green onions and 4–6 inches apart for shallots and leeks, in rows spaced 12–18 inches apart.
Additional Tips:
- Onions grow best in soil rich in organic matter—add compost each season to keep the soil loose and fertile.
- Mulch around plants to retain moisture, suppress weeds, and protect shallow roots from heat and cold.
- Ensure that onions receive consistent moisture, especially during bulb formation, to prevent stress and promote even growth.
Harvest – Bulb & Bunching Onions
Bulb Onions (big and round):
These are typically ready to harvest when the tops turn yellow and fall over, usually around
100–130 days after planting. Once the tops have fallen, gently pull the onions from the soil and
let them cure in a warm, dry, shaded place for several days before storing. Proper curing improves storage life and flavor.
Scallions / Green Onions (thin and long):
These can be harvested much earlier, usually 50–100 days after planting, when they reach a usable
size of about 6–8 inches tall. They can be pulled from the soil and used fresh without curing.
Harvesting regularly encourages new growth and a steady supply of tender greens.
By selecting the right onion varieties and following these harvesting tips, you can enjoy a steady supply of fresh, flavorful onions from your Florida garden throughout the cool season.
Fertilization, Care, and Common Problems
Fertilization (N–P–K Ratio):
Onions benefit from a balanced fertilizer with a slightly higher phosphorus content to support bulb development,
such as 10-20-10 or 8-24-24.
When to Add:
Before Planting: Apply fertilizer to the soil before planting seeds or
transplants to promote strong initial growth and root development.
Mid-Growing Season: Reapply fertilizer about six weeks after
planting to support continued growth and bulb formation.
Application Tips:
- Always follow the directions on the fertilizer package to avoid over-fertilization and salt buildup.
- Apply fertilizer evenly around the base of plants and water thoroughly to carry nutrients down into the root zone.
- Combine fertilizer applications with compost to feed both plants and beneficial soil life.
Pests and Diseases that Affect Onions in Florida:
- Onion Maggots: Larvae that feed on roots and bulbs, causing plants to wilt and die.
- Thrips: Small insects that feed on leaves, causing silvery streaks and reduced vigor.
- Aphids: Sap-sucking insects that cause curling and yellowing of foliage.
- Downy Mildew: A fungal disease that causes yellowing leaves with fuzzy, grayish growth on the underside.
- White Rot: A fungal disease that causes white, fluffy growth on roots and bulbs, leading to decay.
- Botrytis Leaf Blight: A fungal disease that causes grayish-brown spots on leaves and can reduce bulb size.
Blog post on Natural Fertilizers
Natural Pest Control
Companion Plants and Plants to Avoid
Companion Plants for Onions:
| Carrots | Root vegetables known for their sweet, crunchy flavor. Carrots help break up soil, improving aeration and drainage for onions, and benefit from the pest-repelling properties of onions. |
| Lettuce | A leafy green with crisp texture and mild flavor. Lettuce can shade the soil, keeping it cool and reducing weed growth around onions without competing heavily for nutrients. |
| Marigold | Bright, sunny flowers that release chemicals in the soil which deter nematodes and other soil-borne pests. Marigolds help repel nematodes, aphids, and other pests, protecting onion roots. |
| Beet | Root vegetables with sweet, earthy flavor and vibrant color. Beets can help improve soil structure and nutrient availability for onions while sharing similar cool-season conditions. |
| Chamomile | A daisy-like herb known for calming teas. Chamomile attracts beneficial insects like hoverflies and parasitic wasps that prey on aphids and other pests. It also has antifungal properties that can help protect onions from diseases such as downy mildew. |
Plants to Avoid Near Onions:
| Garden Beans | Onions can inhibit the growth of beans, reducing their vigor and overall yield. |
| Peas | Similar to beans, onions can stunt the growth of peas, so it’s best to keep them in separate beds or rows. |
| Sage | A strong-scented herb that can compete for nutrients and has been reported to negatively affect onion growth when planted too close. |
| Asparagus | Onions can negatively affect the growth of asparagus; give each crop its own space in the garden for best results. |
These companion plants help protect onions from pests and diseases while also enhancing the overall health and productivity of the garden. Keeping conflicting crops at a distance gives your onions the best chance to thrive.