Learn how to grow onions at home in Canada in late November with seeds or sets. A complete guide with indoor tips, winter care, and steps for big bulbs.
Late November in Canada can make gardening feel impossible. The ground is frozen, daylight hours are short, and temperatures swing below zero. Most people assume that growing onions at home is something you can only start in spring. But the truth is, with the right method and setup, you can absolutely begin growing onions indoors right now and enjoy fresh, homegrown onions through the entire winter.
This guide is based on long term onion growing experience. It translates traditional outdoor techniques into practical methods for Canadians who want to grow vegetables indoors at the coldest time of the year. We will cover:
• how to start onions from seeds or sets
• which type of onions grow best at your latitude
• how to sow onions indoors in late November
• how to grow multi-sown clusters for high yields
• how to avoid bolting
• how to plant, water, feed, harvest, and store onions
• how to guarantee big bulbs even in Canada’s winter
By the end, you will understand exactly how to never buy onions again.
1. Why Grow Onions at Home in Canada in Late November
1.1 Grocery prices rise sharply in winter
Onions are a kitchen essential, and winter prices climb fast in Canada. Growing onions at home cuts grocery costs immediately.
1.2 Onions adapt extremely well indoors
Onions do not need intense sunlight like tomatoes or peppers. They thrive under moderate light, making them perfect for indoor winter gardening.
1.3 Indoor gardening beats the cold
When outdoor soil is frozen, your indoor onion trays keep producing fresh greens and eventually bulbs.
1.4 Onion scraps become free plants
You can start with seeds, sets, or even the root end of onions you already have in the kitchen.
2. Seeds vs Sets. Which Is Better for Canadians
In gardening forums there is always a debate: start with seeds, sets, or transplants. Each option works, but their performance in Canadian climates differs significantly.
2.1 Growing onions from seed
Seeds are recommended for several reasons.
• Cheaper
• Less likely to bolt
• Bulbs grow bigger
• Better for long day varieties
Bolting happens when onions flower prematurely. It ruins bulb size and sends a tough stem through the center. Indoor growing in winter reduces the bolting risk, and seeds reduce it even further.
2.2 Growing onions from sets
Sets are small onions harvested when young the previous year, then stored and sold in spring. They are convenient, but:
• sets tend to bolt more
• they behave like second year plants
• they sometimes produce smaller bulbs
If you use sets in Canada, choose heat treated sets and plant when your indoor temperature is stable.
2.3 Transplants
These are young onion seedlings grown by professional growers. They work well but are more expensive. You can grow your own transplants indoors easily, so most indoor gardeners skip this option.
3. How to Start Onion Seeds Indoors in Late November
Late November is cold and dark outside, but perfect for indoor seed starting.
3.1 Prepare your materials
You will need:
• plug tray or seedling tray
• fine all purpose indoor potting mix
• onion seeds
• spray bottle
• grow light or bright window
3.2 Sowing method. Multi-sow for higher yields
The best method is multi sowing. This means placing 5 to 8 seeds in each cell or plug. These grow as a cluster from seedling stage to mature bulbs.
Benefits of multi sowing
• no thinning required
• faster planting
• higher yield per space
• easy to transplant clusters outdoors in spring
3.3 Step by step
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Fill trays with sieved potting mix.
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Make small depressions in each cell.
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Drop 5 to 8 seeds in each depression.
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Cover lightly with soil.
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Mist gently with water.
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Place in a warm indoor space.
Onions germinate easily at room temperature. In a warmer home they sprout in 5 to 10 days. Once they reach 2 inches tall, they can grow by a window or under a light.
4. Growing Onions From Sets Indoors
If your local store has onion sets in late fall, you can start them indoors too.
4.1 How to plant sets indoors
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Fill plug trays or pots with potting mix.
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Press each set so that only the tip sticks out.
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Make sure the flat root side is down.
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Water lightly.
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Place under a grow light or near a bright window.
4.2 Spacing for sets
If planting outdoors in spring, sets should be spaced 6 inches apart. Indoors, they can stay in trays until spring or grown for green onions.
5. Choosing the Right Onion Type for Your Latitude in Canada
This is a critical part many beginners overlook.
Day length determines when onions begin swelling bulbs. Canada spans long latitudes, so you must choose the correct type.
5.1 Short day onions
Bulb when day length is 10 to 12 hours.
Not ideal for most of Canada.
5.2 Long day onions
Bulb when day length is 14 to 16 hours.
These are best for British Columbia, Alberta, Ontario, Manitoba, Saskatchewan, Quebec, and the Maritimes.
5.3 Intermediate day onions
Work in mid-latitude zones.
Some Canadian gardeners in southern Ontario or coastal BC may choose these.
6. Planting Onion Seedlings or Sets Outdoors in Spring
Although this article focuses on late November indoor planting, your seedlings will eventually move outdoors in spring.
6.1 Soil preparation
Onions love loose, well drained soil rich in nitrogen. Before planting, mix in:
• compost
• well rotted manure
• chicken manure pellets
Add a 1 inch layer of compost and fork it in lightly.
6.2 Spacing for big bulbs
• Standard bulbs: 6 inches apart
• Champion size bulbs: 10 inches apart
Clusters from multi sowing can be planted 10 inches apart in each direction.
7. Onion Care Through Winter and Spring
7.1 Watering
Onions are shallow rooted. Keep soil moist, not soggy. In winter, water less because indoor soil dries slowly.
7.2 Light
Place onions in a south facing window or use a grow light for 8 to 10 hours daily.
7.3 Feeding
Onions need nitrogen for leaf growth. Feed with:
• diluted liquid fertilizer
• blood meal
• fish emulsion
Feeding every 2 to 3 weeks helps produce thick, healthy leaves that support large bulbs.
8. Avoiding Weeds, Disease, and Bolting
8.1 Weeds
Onions hate competition. Indoors, weeds are rare. Outdoors, hand weed carefully because onions have shallow roots.
8.2 Disease
Good airflow reduces fungal issues. Indoors, spacing trays and providing ventilation solves the problem.
8.3 Avoiding bolting
To reduce bolting:
• grow from seeds
• avoid temperature swings
• avoid planting sets too early
• choose heat treated sets
9. Harvesting and Curing Onions
9.1 Harvesting
Outdoor bulbs are ready when:
• the neck softens
• the tops flop over
• half to two thirds of the leaves have fallen
Indoors, you can harvest green onions any time.
9.2 Curing
Place bulbs in a dry, airy place for 2 to 3 weeks. This forms a papery skin that protects the onion.
9.3 Storage
Store cured onions in:
• mesh bags
• hanging braids
• open baskets
Long day onions store exceptionally well through winter.
10. Indoor Onion Growing in Late November. Special Canadian Tips
• Keep trays away from freezing windows.
• Use grow lights to compensate for short days.
• Choose long day varieties for spring transplanting.
• Start seeds now for strong seedlings by March.
• Grow green onions indoors for continuous winter harvests.
FAQs
1. Can I grow onions indoors in Canada in late November?
Yes. Green onions and onion seedlings grow very well indoors during winter.
2. Should I start onions from seeds or sets in winter?
Seeds are better indoors because they bolt less and grow larger bulbs.
3. Do I need a grow light to grow onions in winter?
Strongly recommended because daylight hours are short in Canada.
4. How long does it take for onion seeds to germinate indoors?
Usually 5 to 12 days depending on temperature.
5. Can I plant onion seedlings outdoors in spring?
Yes. Wait until the soil is workable and has warmed slightly.
If you are ready to never buy onions again, this is the perfect time to start.
Begin your seeds indoors this week and enjoy steady indoor harvests through winter and big bulbs in summer.
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