How to blanch vegetables for the freezer: boil them briefly, usually 2 to 5 minutes by Health Canada's guidance, then plunge them into ice water to stop the cooking. Learning it takes one afternoon, and I'd call it the step that decides whether a fall harvest still tastes like itself in February. Almost every vegetable needs blanching before freezing; onions and sweet peppers are the common exceptions.
Blanching is a short boil followed by an ice-water plunge, done before vegetables go into the freezer. I write these guides for Merit Home Furniture from Duncan, in the Cowichan Valley. Every Saturday, year round, the Duncan Farmers' Market fills Craig Street and Ingram Street, where our store is, with more than 100 vendors by Tourism Cowichan's count.
Market beans, farm-stand corn or your own kale: the method is the same. Merit's freezers are appliances we keep up-Island, at our Campbell River and Port Alberni stores. The last table shows how much fresh food each size can freeze in a day.
How to blanch vegetables, step by step
Blanching vegetables at home takes a big pot with a lid, a wire basket that fits inside it, a bowl of ice water and a colander. The University of Saskatchewan's Gardenline asks for 4 L of water to about 500 g of vegetables, and 8 L for leafy greens.
- Wash and cut. Rinse under cool running water and scrub firm vegetables with a brush. Cut even pieces, sized the way you'll cook them later.
- Boil the water. Fill the pot about three quarters full and bring it to a hard boil on high.
- Lower in one batch and cover. The National Center for Home Food Preservation says the water should boil again within 1 minute. If it doesn't, the batch is too big for the pot.
- Time it from the boil, using the chart below for that vegetable and size.
- Ice bath. Move the basket straight into the ice water and leave it about as long as it boiled.
- Drain and dry. Tip the vegetables into the colander, then spread them on a towel. Water left on them turns to ice in the bag.
Gardenline adds that the same blanch comes before drying vegetables in a dehydrator.
Do vegetables have to be blanched before freezing?
Most vegetables do have to be blanched before freezing, because their enzymes keep working in the cold. Gardenline explains that blanching destroys the enzymes that ripen a vegetable and change its flavour, colour and texture. The National Center adds that it cleans the surface, brightens the colour and slows the loss of vitamins.
Timing cuts both ways. The National Center warns that underblanching stimulates the enzymes and is worse than no blanching at all, while overblanching costs flavour, colour, vitamins and minerals.
Blanching times by vegetable, from two published charts
Blanching times come from tested charts, and these are the two I'd keep on the fridge door. Gardenline at the University of Saskatchewan draws on the Ontario agriculture ministry's freezing guide. The National Center is at the University of Georgia. Times are minutes in boiling water. The National Center starts the clock when the water boils again; Gardenline starts it as the basket goes in, with the heat on high.
| Vegetable | Gardenline (USask) | National Center (UGA) |
|---|---|---|
| Asparagus | Medium 3, large 4 | Small 2, medium 3, large 4 |
| Green or wax beans | Cut 3, whole 4 | 3 |
| Broccoli | Medium 3, large 4 | 3, or 5 steamed |
| Brussels sprouts | Small 3, medium 4, large 5 | Small 3, medium 4, large 5 |
| Cabbage | Wedges 2, shredded 1 | Shredded 1 1/2 |
| Carrots | Cut 3, whole 5 | Diced or sliced 2, small whole 5 |
| Cauliflower | 3 | 3 |
| Corn, kernels | 4 | 4, blanched on the cob before cutting |
| Corn on the cob | Small 7, medium 9, large 11 | Small 7, medium 9, large 11 |
| Green peas, shelled | 2 | 1 1/2 |
| Spinach and chard | 2 | Greens 2, collards 3 |
| Summer squash | 2, in 1 cm slices | 3 |
| Parsnips and turnips | Parsnips 1, turnip 2 | Cubes 2 |
| Winter squash | 2, peeled and diced | Cook it first |
The charts differ by a minute here and there, mostly on piece size. Gardenline cuts broccoli and cauliflower to about 3 cm across; the National Center uses broccoli florets an inch and a half across and cauliflower florets an inch across. Pick one chart and cut to its sizes.
How long do you blanch green beans?
Green beans take 3 minutes cut and 4 minutes whole by Gardenline, after trimming the ends. Cut about 3 cm long, they're ready for a stir fry.
How do I blanch carrots?
Carrots lose their tops and get a peel or a scrape. Gardenline blanches small whole carrots for 5 minutes, and 1 cm slices, dice or fingers for 3 minutes. The National Center gives diced or sliced carrots 2.
Boiling water or steam: two ways to blanch vegetables
Boiling water is the National Center's choice for home freezing, which it calls the most satisfactory way to heat all vegetables. For broccoli, pumpkin, sweet potatoes and winter squash, steam works too. Steam blanching takes about one and a half times as long. The vegetables go in a single layer, in a basket at least 3 inches above the bottom of a tightly covered pot.
Can you blanch vegetables in the microwave?
The National Center for Home Food Preservation says microwave blanching may not work, since some enzymes may survive it, and that it doesn't save time or energy. I'd keep the microwave for reheating.
Vegetables that don't need blanching before freezing
Health Canada's blanching page names onions and peppers as vegetables that freeze without blanching, plus tomatoes unless you're blanching to slip the skins off. For peeling, the National Center dips tomatoes in boiling water for 30 seconds to loosen the skins.
The National Center has diced onions going in raw, to be used within a few months. Sweet peppers can go in raw for cold dishes, or get 3 minutes for halves and 2 for strips if they're headed for cooking.
Lettuce is the vegetable not to freeze at all: Health Canada's storage chart marks leaf and iceberg lettuce "don't freeze". Blanching zucchini for aquarium fish is a pet care question, better put to the fish store or a vet who treats fish.
How to blanch vegetables to freeze: cooling, drying and packing
Blanched vegetables freeze better cold and dry. Health Canada's steps end with the drained pieces spread on a covered sheet pan in the freezer, then moved to a freezer-safe container once frozen.
Freezer burn is the grey, dried patch where air has reached the food. Iowa State University Extension explains that surface ice turns straight to vapour and leaves the outer layer dry and discoloured. It affects quality, not safety. Squeeze the air out of each bag, or use a vacuum sealer, and label it with the contents and the date.
The National Center says to add only what will freeze within 24 hours, usually 2 to 3 pounds of food per cubic foot of freezer space.
Freezer temperature and how long blanched vegetables keep
A home freezer belongs at -18°C (0°F) or colder, by Health Canada's food safety advice. Its blanching page puts frozen vegetables at up to 12 months, and its storage chart, written for quality, breaks that down.
| Vegetable | Freezer at -18°C |
|---|---|
| Green or wax beans | 8 months |
| Carrots, celery, spinach, squash | 10 to 12 months |
| Tomatoes | 2 months |
| Leaf or iceberg lettuce | Don't freeze |
A freezer thermometer is the easy check that the dial tells the truth, especially in a garage.
Freezing a Cowichan Valley harvest: how much a freezer takes in a day
A freezer's size sets how much of a harvest day it can take. At the National Center's 2 to 3 pounds per cubic foot, here is a day's load on some freezers Merit lists. Prices are before applicable taxes, read November 1, 2026.
| Freezer | Price and store | Fresh food per day |
|---|---|---|
| Danby 5.0 cu. ft. chest | $319.99, Campbell River and Port Alberni | 10 to 15 lb |
| Frigidaire 13 cu. ft. upright, frost-free | $749.00, Campbell River and Port Alberni | 26 to 39 lb |
| Danby 14.0 cu. ft. upright, frost free | $859.99, Campbell River and Port Alberni | 28 to 42 lb |
| Frigidaire 15 cu. ft. chest | $899.00, Campbell River and Port Alberni | 30 to 45 lb |
| Amana 16 cu. ft. upright, Fast Freeze | $1,099.99, Port Alberni | 32 to 48 lb |
| Frigidaire 20 cu. ft. chest | $1,099.00, Campbell River and Port Alberni | 40 to 60 lb |
So 40 pounds of corn kernels is a three or four day job for the small Danby chest, and one day for the 20 cubic foot Frigidaire. Four of the six say "garage ready" in their listing titles. Merit's freezer collection lists 80 models; 42 are carried at Campbell River, Port Alberni or both, and the rest are special orders. It splits into chest freezers and upright models.
A drinks fridge won't stand in for a freezer, as the temperatures wine coolers and beverage centres run at make plain. Danby also makes the Silhouette line, and Danby's in-home service limits on the Island are worth knowing before buying either. For why an Island-owned store matters after the sale, here is what we do once the delivery truck leaves.
Where blanching vegetables goes wrong
- Too big a batch. If the water takes over a minute to boil again, the enzymes may not be stopped.
- Guessing the time. Short blanching can leave vegetables worse than none. Use the chart and a timer.
- Skipping the ice bath or the drying. The pieces keep cooking, or freeze into clumps coated in ice.
- Overloading the freezer on harvest day. Food that freezes slowly may lose quality, the National Center says.
- A freezer running warmer than -18°C, the temperature Health Canada's storage times are written for.
Where these blanching times and freezer facts come from
- Health Canada, Canada's food guide, How to blanch vegetables, checked November 2026.
- Health Canada, Safe food storage (fridge and freezer storage chart), checked November 2026.
- University of Saskatchewan, Gardening at USask, Blanching Vegetables, checked November 2026.
- National Center for Home Food Preservation, Blanching Vegetables and Blanching Times, checked November 2026.
- National Center for Home Food Preservation, Freezing Pointers and Packaging and Labeling Foods, checked November 2026.
- National Center for Home Food Preservation, Freezing Onions, Freezing Bell or Sweet Peppers and Freezing Tomatoes, checked November 2026.
- Iowa State University Extension, AnswerLine, Freezer Burn and Food Safety, checked November 2026.
- Tourism Cowichan, Duncan Farmers' Market, checked November 2026.
- Merit Home Furniture freezer listings, prices and stores read November 1, 2026.
Asking about a freezer at our Campbell River or Port Alberni store
Merit's freezers are at our Campbell River and Port Alberni stores. Call the store a listing names to ask what's set up to look at and what delivery to your area involves. A rough idea of how much you freeze in a year helps, along with the space, measured.
Freezers at Campbell River, (250) 286-0868
Freezers at Port Alberni, (250) 724-6644
More on fridges, freezers and the rest of the kitchen is on our appliance guide page.