Downsizing your garden? Moving to a smaller yard? Want to still enjoy home-grown onions? Growing onions in containers could be your answer! Container gardening differs from conventional gardening a bit. We have summarized and provided the essentials for growing onions in containers below.
Growing onions in containers is a great way to enjoy fresh homegrown onions even if you don’t have a lot of garden space. When grown in pots onions can thrive on a sunny balcony, patio, or deck. With just a little effort, you’ll be harvesting onions to use in your favorite recipes in no time!
Why Grow Onions in Containers?
There are several benefits to growing onions in containers:
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Great for small spaces You don’t need a large garden plot to grow onions, A pot on a balcony or deck works perfectly
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Convenient harvesting Pulling onions from containers is easier on your back than bending over in a garden bed,
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Better drainage: Onions are prone to rotting if soils get too wet. Containers provide better drainage.
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Weed control: Weeding is much easier when onions are contained.
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Mobility: Pots can be moved to take advantage of changing sunlight patterns.
Choosing the Right Container
You’ll need a container that’s at least 10-12 inches deep and 8-10 inches wide. Shallow pots will restrict bulb growth. Look for containers with drainage holes to prevent soggy soil. You can grow 3-4 onions in a 10 inch pot. For more onions, use a larger container or planter box.
Materials like plastic, clay, wood, and ceramic all work well. Just ensure the container is sturdy and won’t blow over in wind. Dark colored pots absorb heat, which can help speed growth.
Getting Started with Seeds vs. Sets
You can grow onions from seeds or sets:
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Seeds: Provide more variety options but take longer. Start seeds indoors 6-10 weeks before your last spring frost.
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Sets: Quicker but less variety. Sets are immature onion bulbs you plant directly in pots outdoors in spring.
Sets are simpler for beginners but both methods work! Choose based on time available and variety preferences.
Choosing the Best Onion Variety
There are three main types of onions:
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Short day: Best for southern regions. Need 10-12 hours of daylight to form bulbs.
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Long day: Better for northern regions. Require 14+ hours of sun to bulb.
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Day neutral: Adaptable to various day lengths. Good for intermediate zones.
Talk to local gardeners or search for varieties recommended for your growing zone. Red, yellow, and white onion colors are all suitable for containers.
Popular container varieties include ‘Candy’ and ‘Red Wethersfield’. Miniature cocktail onions also grow well in pots.
Getting the Soil Right
Onions need loose, nutrient-rich soil. Aim for a mix of:
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1/3 potting soil or compost – Provides nutrients
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1/3 peat or coir – Improves drainage
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1/3 vermiculite or perlite – Retains moisture
You can buy premixed potting soils, or mix your own. Stir in a balanced organic fertilizer prior to planting. The soil should feel crumbly, not heavy or muddy.
Planting Your Onion Sets or Seedlings
For sets: Push sets 1-2 inches deep in soil, pointed ends up. Space 2-4 inches apart. Pat soil gently around sets.
For seedlings: Use a trowel to dig holes 2-3 inches deep. Place seedling roots down and fill holes with soil. Water soil thoroughly after planting.
Place pots in full sun. A southern exposure is ideal. As plants grow, provide support by driving stakes into pots and loosely tying onion tops to stakes.
Caring for Container Onions
Watering: Check soil daily, water when top 1-2 inches become dry. Avoid overwatering.
Fertilizing: Apply balanced organic fertilizer every 2-3 weeks after plants are established.
Weeding: Remove weeds when small to reduce competition. Mulching atop soil prevents weeds.
Pests: Watch for thrips and onion maggots. Remove insects by hand or use insecticidal soap if needed.
Bolting: Remove flower stalks immediately to prevent bolting, which reduces bulb size.
Harvesting Onions
Onions are ready to harvest when tops turn yellow and fall over. This takes 60-120 days, sometimes more for seed-grown onions.
Gently pull onions once the majority of tops are yellowing. Rinse off excess dirt (don’t wash). Remove foliage, leaving 1-2 inches of stem attached.
Cure onions in a warm, dry spot out of direct sun for 1-2 weeks. Once thoroughly dried, store cured onions in a cool, dry area. Your harvest will last for months!
Tips for Growing Great Onions in Containers
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Choose sturdy containers with drainage holes and enough depth for bulbs.
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Pick the best varieties for your climate – long day, short day, or day neutral.
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Prepare soil with a mix of compost, peat or coir, and perlite or vermiculite.
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Plant seeds indoors 6 weeks before last frost, or plant sets directly in pots.
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Place containers in full sun and provide support stakes as onions grow.
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Water when soil surface is dry, fertilize every 2-3 weeks.
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Watch for pests like thrips and onion maggots. Remove any flower stalks.
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Harvest onions when tops turn yellow and fall over, then cure for 1-2 weeks.
With the right containers and care, you can grow an abundant onion harvest on a balcony, patio, or deck. Homegrown onions make any dish taste better!
Soil requirements for onions
Onions grown in containers will do best in well-draining, loamy soil with a slightly acidic pH. Be sure to enrich the soil with a balanced fertilizer or mature compost before planting.
Container selection and location
The most important factor is ensuring that your onions have enough room to grow. Onion containers must have at least 10″ of soil depth. The diameter can be any size as long as each onion has 3″ to 4″ of room to grow. You can use a 5 gallon bucket, planter box, or any sturdy container you may have. Be sure the container has good drainage holes and try to elevate it 1″ to 2″ off the ground.
Just like conventional onion growing, place your container where it will receive the maximum hours of direct sunlight. Onions grown indoors will require added day-length hours and heat units from artificial light; it may be easier for Mother Nature to handle the temperature curve.
How to Grow Onions in Containers & Raised Beds
FAQ
How many onions can I plant in a container?
A 5-‐gallon bucket works fine for growing 6 or 8 onions. A large planter box works great, or even a plastic tub.
What month do you plant onions?
2. Plant the onions in late March or early April. For best growing conditions, plant your onions as soon as you can work the ground. Typically, this happens in the springtime right after the last frost. 3. Pick a spot in your garden with full sun. Onions grow best in direct sunlight for most of the day.
What is the best container to grow onions in?
You can use a 5 gallon bucket, planter box, or any sturdy container you may have. Be sure the container has good drainage holes and try to elevate it 1″ to 2″ off the ground. Just like conventional onion growing, place your container where it will receive the maximum hours of direct sunlight.
Can you grow onions in containers?
Onions are a staple of many vegetable gardens and can even be grown in small yards, on patios, or even on balconies. Growing onions in containers is a fantastic way to cultivate a range of bulbs and enjoy using your homegrown produce in the kitchen. It opens up opportunities for everyone to grow a simple crop in even the smallest of spaces.
How to plant onion sets in a container?
Fill the container with potting soil. Place the onion sets 2 inches apart and 1 inch deep in the soil. Water the onions thoroughly. Place the container in a sunny location. Water the onions regularly, especially during dry spells. The onions will be ready to harvest in about 3 months. “` How To Plant Onion Sets In Containers?
How much water do onions need to grow in a container garden?
Water is important to growing onions in container gardens because your container onions will have little access to naturally stored rainfall from surrounding soil like onions grown in the ground do. Onions grown in containers will need at least 2 to 3 inches (5-8 cm.) of water a week, perhaps even more in hot weather.
How do you grow onions in a 5 gallon container?
You can use a 5 gallon bucket, planter box, or any sturdy container you may have. Be sure the container has good drainage holes and try to elevate it 1″ to 2″ off the ground. Just like conventional onion growing, place your container where it will receive the maximum hours of direct sunlight.
Can you grow onions indoors?
Onions grown indoors will require added day-length hours and heat units from artificial light; it may be easier for Mother Nature to handle the temperature curve. Onions grown in containers will do best in well-draining, loamy soil with a slightly acidic pH. Be sure to enrich the soil with a balanced fertilizer or mature compost before planting.
How big should an onion container be?
Onion containers must have at least 10″ of soil depth. The diameter can be any size as long as each onion has 3″ to 4″ of room to grow. You can use a 5 gallon bucket, planter box, or any sturdy container you may have. Be sure the container has good drainage holes and try to elevate it 1″ to 2″ off the ground.