Quebec gardeners get two workable windows for Asian greens. The first opens in spring once the soil has warmed after the last frost, which averages May 6 near Montreal. The second runs from midsummer to the first fall frost, which averages October 5. The fall window usually gives the better crop, because spring sowings run into lengthening days and bolt.
When the soil is warm enough in Quebec
At the Montreal/St-Hubert A station, the last spring frost falls on average on May 6, according to Environment and Climate Change Canada’s 1981-2010 climate normals. That is a mean date. In one year out of two, frost arrives later. Northern and upland districts run weeks behind this station, so a gardener in the Laurentians or the Saguenay should push the calendar back accordingly.
Soil warms after the frost risk ends, and it warms slowly. A bed can be frost-free on May 6 and still be cold, wet and slow to wake up. Asian greens germinate in cooler soil than beans or squash do, which is why they are among the first things to go in. They still sulk in sodden ground, and seed sown into cold mud can rot before it sprouts.
How do you check the soil before sowing Asian greens?
Use your hands first. Take a handful from the top few inches. If it crumbles when you squeeze it, the bed is ready. If it smears or forms a slick ball, wait. Then push a soil thermometer about 2 inches down and read it in the morning, several days running. The reading should have stopped swinging with each cold snap or warm afternoon.
Dark beds in raised frames dry out and warm up sooner than flat ground. A sheet of clear or black plastic laid over the bed a week or two ahead of sowing helps too. Pull it off before you sow.
Which types can go in first?
Go with the quick, small types: baby-leaf mustards, tatsoi, komatsuna-type greens and small bok choy. They take a light frost once they are up, and they finish before the long days of late June push them to flower. A floating row cover laid over the sowing protects against a late frost and keeps flea beetles off the seedlings, which are most active in spring. That is a practice, not a spray, and it works better.
For the varieties that have been trialled in your own district, ask the provincial agriculture ministry. MAPAQ is the Quebec counterpart of a US state extension service. Seed catalogs from other regions can promise a lot, but local trial results are the better guide.
How long the season lasts here
The Saint-Hubert station has about 152 frost-free days between the mean last spring frost (May 6) and the mean first fall frost (October 5). Both are mean dates. Half of all years bring the last frost later, and half bring the first fall frost earlier. Treat a sowing that finishes on October 5 as a coin toss.
That window is long enough for two full sowings of fast greens, plus a small third one if you clear a bed in July. The spring crop comes out in early summer, the bed gets fresh compost, and the second sowing goes in from midsummer on. This is where Quebec has an edge over cooler districts further north. In a window of, say, 100 days, the spring sowing might be the only one that has time to finish.
How do you work back from the first fall frost?
Take the days to maturity on the seed packet. For direct-sown greens, the count starts at sowing. Count backward from October 5, then add about two weeks, because growth slows as the days shorten and the nights cool. A bed sown on that date will often reach harvest size a bit later than the packet suggests.
Small sowings every couple of weeks in late summer spread the harvest and cover you if one batch gets caught by an early frost. The succession sowing approach covered elsewhere on this site works well here. Make each sowing the length of a short row rather than a whole bed.
Is transplanting worth it?
With 152 days to work with, direct sowing is enough for most Asian greens. Transplants earn their place in one case: an early start for bok choy or napa-type cabbage under cover in April. Even then, rough handling can check the roots and send the plant to seed early. Start them in cells, keep the root ball intact, and set them out while still small. Look at the roots before you plant. A pot-bound mass of circling white roots is a sign to skip that plant.
The Canadian normals cover 1981-2010, while the US figures on this site cover 1991-2020, so the two sets of dates are not strictly comparable. For a contrast with a milder, wetter climate, see Growing Asian Greens in Oregon. For a continental one with hotter summers, see Growing Asian Greens in Iowa.
Heat and water in Quebec
Southern Quebec summers are warm and humid, with hot spells that come and go within days. Summer heat is a smaller threat here than in the Midwest. It still matters, because a few hot days in a row can send a crop of bok choy to seed. Shade cloth over a midsummer sowing and a thick mulch around the roots are enough to protect most beds.
The bigger risk is damp. Rain falls through the summer, and humid air lingers in the garden after it. Cool, wet weather brings downy mildew on the leaves, slugs in the rows, and slow, leggy growth. In wet years, spacing is the main defense. Give plants room for air to move, water at the base in the morning, and pick off damaged outer leaves. Soilborne troubles such as clubroot build up in the ground over several seasons.
Asian greens are brassicas, and so are turnip and rutabaga. They share their pests and diseases with cabbage, kale and mustard. A gardener who rotates bok choy into a bed where cabbage grew last year has rotated nothing. Follow the rotation guide on this site, and count every one of these crops as the same family. The parent page, Growing Asian Greens: Fast, Cold-Hardy, and Prone to Bolting, covers the family in more detail.
What does the first frost mean for Asian greens?
This crop belongs to the second half of the year, so the first fall frost matters more than any heat. It sets the last date a sowing can still finish. A light frost usually does little harm to the hardy types, and some taste sweeter after one. A hard freeze finishes most of them. Cover a bed with a row cover or low tunnel on the first cold nights to buy another week or two of harvest.
Can any Asian greens stand through a Quebec winter?
The mean daily minimum of the coldest month at Montreal is -14.1 °C (6.7 °F), and individual nights run colder. Montreal sits in zone 5b of the Canadian hardiness system, which does not convert to a USDA zone. In open ground, Asian greens end with the first hard freeze. Under a tunnel, cold frame or thick mulch, the hardiest leaf types can hold on for part of the winter. A cover softens the cold but does not remove it, so expect the crop to give out at some point. Harvest what you can before then, and ventilate covers on mild days to keep rot from setting in.
Which Asian greens suit Quebec
Start from the territory, because a short season favours the earliest types and a damp one makes disease resistance the first thing to check on the seed packet. A summer with occasional heat adds one more thing to watch: how well a type holds up before it bolts.
| Type | Best sowing window | Main risk in Quebec |
|---|---|---|
| Baby-leaf mustards and tatsoi | Early spring and late summer | Flea beetles in spring, slugs in wet weather |
| Small bok choy and komatsuna-type greens | Early spring and from midsummer on | Bolting in long June days, mildew in damp spells |
| Napa-type cabbages | Midsummer, timed to finish before the first frost | Rot in wet autumns, early frost |
| Daikon-type roots | Midsummer to late summer | Soil moisture swings, root pests |
Fast types suit the first sowing, because they finish before the day length triggers flowering. The slower napa types suit the fall sowing, since the cooling nights keep them from bolting. In a wet year, look on the packet or in the catalog for disease-resistance notes. A type listed as tolerant of mildew or bolting is worth the extra care over one that is not.
Varieties are another matter, and no list from outside the region will serve you well. Performance depends on the district: the soil, the elevation, how long the snow stays, how humid the summer runs. A name that did well in a trial in another province or in the northern US can fail a few counties away. The reliable answer comes from MAPAQ and the regional growers who have trialled seed in your area. Ask what has done well for them in your district, then buy only a small amount of any new seed in its first year.
If you grow a root type such as daikon and want to hold some back after harvest, inspect each root before it goes into storage. A soft patch, a weeping spot or a moldy crown ends the question. Discard that root and do not trust one that merely looks sound on the outside. Keep it away from any root that has started to go soft.
Common questions
When can I sow Asian greens outdoors in Quebec?
Sow once the soil is workable and the morning reading has settled, usually soon after the last frost. Near Montreal that frost averages May 6, and it comes later in northern and upland districts. A second sowing goes in from midsummer, timed to finish before the first fall frost, which averages October 5 at the same station.
Do Asian greens survive Quebec winters?
Not in open ground. The mean daily minimum of the coldest month at Montreal is -14.1 °C (6.7 °F), and the greens end with the first hard freeze. The hardiest leaf types can last longer under a tunnel, cold frame or heavy mulch. They do not survive the full winter.
Why do my Asian greens bolt in June?
Long days and a stretch of heat trigger flowering. A cold snap after sprouting can add to it. Sow bolt-tolerant types in spring, keep the soil evenly moist, and shade plants through warm spells. If the plants are bolting anyway, move the main sowing to late summer, when the days are getting shorter.
Can I plant Asian greens where cabbage grew last year?
No. Asian greens, cabbage, kale, mustard, turnip and rutabaga are all brassicas and share the same soilborne diseases and pests. Rotating one into another’s bed gains you nothing. Rotate by plant family and leave several years before brassicas return to the same ground, longer if clubroot has ever shown up.