Can onions be grown successfully in containers?
Written by
Olivia Mitchell
Reviewed by
Prof. Martin Thorne, Ph.D.Choosing to grow onions in containers gives the gardener much greater flexibility. Go for 'White Lisbon' or 'Purplette' which have been bred specifically for pots. Use at least 18in deep containers to allow for good root growth. Mine live out on my balcony and give delicious flavours throughout the year: your little space can yield terrific results.
Fill the containers with well-draining soil (I like a 3:1 potting soil to compost mixture for my containers, add perlite if your soil is too dense, stopping about two inches from the rim of the container for watering). Depending on the plants you will grow in your containers you may want to mix compost (or worm castings) to provide slow-release nutrition. The quality of your soil makes or breaks the success of your container garden!
Position your containers in full sun locations that receive 6 hours or more of direct sunlight daily. Rotate your pots weekly to ensure they grow evenly all around, or you'll end up with a lopsided bulb. During any heat spells, you may move your pots to afternoon shade. I use wheeled plant stands for easy repositioning of my bulbs. How you manage the light will determine how evenly your bulbs will develop.
Planting
- Space plants 4 inches apart
- Plant sets 1 inch deep
- Water thoroughly after planting
Maintenance
- Water when top inch soil dries
- Apply liquid seaweed every 3 weeks
- Rotate containers every 3 days
Temperature Control
- Move indoors below 40°F
- Provide shade above 85°F
- Use mulch to regulate soil heat
Water container onions more often than garden ones. Check the soil moisture daily in summer. Container earths dry out faster than garden earths, especially in terracotta pots. As you are aware, I strongly recommend the self-watering pots. Bulbs grown in these do not suffer the anxious moments connected with watering done in the garden. Your care will prevent stunting of bulbs.
Harvest green onions when the stems are the size of pencils. If you're growing bulbs, wait until the tops are yellow and fall over. Remove whole plants from the container carefully. I practice succession planting, so I'll have more. Still, you will have fresh onions almost all year round from your container garden.
Container growing offers you the pest avoidance advantage about growing plants. Raising pots can reduce the risk of slugs and snails crawling into your plants. Fresh potting mix is unlikely to be infected with soil-borne diseases. I do not use any chemical treatments, so experiencing an organic approach helps grow healthy, tasty onions.
Read the full article: How to Grow Onions Successfully at Home
