How to Make Green Tomato Relish in Canada (Chow-Chow)

Every Canadian gardener meets the same problem in late September: the frost is coming, and half the tomatoes are still hard and green. Green tomato relish — chow-chow, as it’s known from the Maritimes to rural Ontario — is the traditional answer. It turns the unripe crop that would otherwise go to the compost into a sweet-tangy, mustard-spiced condiment that lasts the winter.

This guide covers the Bernardin water-bath method. Per our food-safety policy we cite Bernardin for the exact vinegar amount and processing time rather than reprinting them — this is a recipe to make from a tested edition, with this page explaining the how and why.

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The rule that keeps chow-chow safe: don’t cut the vinegar

Green tomatoes are a bit more acidic than ripe ones, but a chow-chow also carries onions — and often peppers — which are low-acid. On their own, the finished vegetables aren’t reliably below the pH 4.6 line that separates water-bath-safe from pressure-canning-required.

Use the full vinegar amount (5% acidity) your tested Bernardin recipe calls for. Never reduce it to soften the tang.

This is the same logic as corn relish and bread-and-butter pickles: low-acid vegetables are only safe in a boiling-water bath when a tested recipe acidifies the whole batch. Sugar and spices you can nudge to taste — they’re flavour, not safety. The vinegar is safety.

The overnight salt draw

The one step that separates a good chow-chow from a watery one:

Layer the chopped green tomatoes and onions with pickling salt and leave them overnight. This pulls the water out so the relish cooks down thick instead of weepy — and so the vinegar stays concentrated rather than diluted.

In the morning you drain thoroughly (and rinse off some of the salt if you prefer a milder result). The salt is a texture step, not the safety step — the vinegar still does the food-safety work.

What you need

• About 2.5 kg green (unripe) tomatoes — firm, hard, tart; the frost-crop
• 2–3 onions, plus peppers if your recipe calls for them
• Pickling salt for the overnight draw (non-iodized)
• Vinegar at 5% acidity — the amount in your tested recipe
• Sugar and whole pickling spices — mustard seed, celery seed, turmeric
• A large non-reactive bowl (glass or stainless — not aluminium) and a heavy pot
• 250 or 500 mL Bernardin jars with new SNAP lids

Method

1. Chop and salt. Core and chop the green tomatoes and onions. Layer with pickling salt in a non-reactive bowl, cover, and leave overnight (~12 hours).
2. Drain. In the morning, drain thoroughly in a colander; press or rinse to shed excess salt. Discard the liquid.
3. Cook with the vinegar. Combine the drained vegetables in a heavy pot with sugar, spices, and the full amount of vinegar your recipe specifies. Boil, then simmer, stirring often, until thick — usually 30–45 minutes.
4. Fill. Ladle hot relish into hot jars, leaving the headspace your Bernardin edition gives (usually 1 cm / ½ inch). Debubble; wipe rims; apply fresh SNAP lids fingertip-tight.
5. Process in the boiling water bath for the time in your Bernardin edition for green tomato relish, at your altitude band. Time starts at a full rolling boil.
6. Cool and check. Rest 5 minutes in the canner, lift to a towel, and leave 12–24 hours before checking seals.

If a jar doesn’t seal: the 24-hour rule applies.

Wait two weeks before eating

Like all relishes, chow-chow improves with jar-aging. Give it two weeks for the vinegar to mellow and the spices to meld before the first jar comes open.

Storage

• Cool, dark, dry place at room temperature
• Best quality about 12 months
• After opening: refrigerate, use within 1–2 months
• Inspect before opening — discard any jar that bulges, leaks, or smells off

Ways to use green tomato relish

• The Maritime classic: on fish cakes and beside fried fish
• On hot dogs, burgers, and sausages
• Alongside roast pork, ham, or a Sunday roast
• Stirred into potato or egg salad
• On a cheese-and-cracker board
• Folded into a sharp cheddar sandwich

Common problems

• Relish is watery. The salt draw was skipped or too short, or the vegetables weren’t drained well. Salt overnight and drain hard next time.
• Too sharp / too sweet. Adjust sugar within reason next batch — but never lower the vinegar below the tested amount.
• Jar didn’t seal. The 24-hour rule.
• Bulging lid after weeks. Discard the whole jar; don’t taste. Low-acid vegetables in inadequate vinegar can support spoilage.

Next steps

• How to make corn relish — the late-summer relish, same vinegar-safety rule
• How to make bread-and-butter pickles — same mustard-celery spice family
• How to make fermented green tomatoes — the no-canning, lacto route for green tomatoes
• Canning altitude adjustments — required reading
• How long does home-canned food last — shelf-life context
• Water-bath canning pillar — the broader method