The best Asian greens for Quebec are the quick, cool-loving leaf types: bok choy, tatsoi, mizuna, komatsuna and mustard greens. Napa cabbage and Chinese broccoli earn a spot as fall crops sown in summer. Heat-lovers such as water spinach are a gamble. The season is long enough for the first group and tight for the last.
The short answer for Quebec
Choose compact, fast leaf types first and slow heading types second. Bok choy, tatsoi, mizuna, komatsuna and the milder mustard greens can be cut as baby leaves in roughly three to five weeks from sowing. They also tolerate light frost, which matters at both ends of a northern season.
The Montreal/St-Hubert reference station has about 152 frost-free days between the mean last spring frost (May 6) and the mean first fall frost (October 5). Both dates are averages from Environment and Climate Change Canada’s 1981-2010 normals. In one year out of two, the last frost falls later than May 6, and in one year out of two, the first fall frost arrives before October 5. Treat each date as the middle of a window.
Which Asian greens suit a short season?
The table sorts the common types by how they behave in a season of this length. “Fast” means harvestable as young leaves within about five weeks of sowing.
| Type | Speed | Frost tolerance | Best use in Quebec |
|---|---|---|---|
| Tatsoi, mizuna, komatsuna | Fast | Good | Spring and fall, baby leaf or cut-and-come-again |
| Bok choy (compact types) | Fast to medium | Good for light frost | Early spring and late summer sowings |
| Mustard greens | Fast | Good | Spring and fall, picked young before they turn hot and coarse |
| Napa cabbage | Slow (forms a head) | Moderate | Fall crop sown in mid to late summer |
| Chinese broccoli, choy sum | Medium | Moderate | Spring or fall, cut before flower buds open |
| Water spinach, amaranth-type greens | Needs sustained heat | None | Marginal, only in the warmest sites |
If you grow only three, make them tatsoi, bok choy and mizuna. They cover cool spring, late summer and fall with almost no change in technique, and they can be sown again every couple of weeks. A broader look at the whole crop group is in Growing Asian Greens in Quebec.
Why does the fall crop often beat the spring crop?
Asian greens bolt when days are long and warm. A spring sowing grows into lengthening days and then summer heat, so plants can send up flower stalks before they size up. A sowing made in late summer does the reverse: days shorten, nights cool, and leaves stay sweet and tender. Many Quebec gardeners find their best bok choy and napa come from the fall window, and a light frost often improves the flavor.
What will not work here
Water spinach tops the list. It wants warm soil and weeks of steady heat, and a mean last frost of May 6 leaves little room before the first fall frost cuts it off. Other tropical-leaning greens, such as Malabar spinach, face the same wall. A few warm summers may reward you, but a cool one will not.
Napa cabbage sown in early spring is the second common failure. It needs cool weather to build a tight head, and a spring sowing is likely to bolt as days lengthen before the head forms. Sow it in summer, timed so the head fills in cool fall weather and is harvested before hard freezes arrive.
Planting out tender seedlings on May 6 because it is “the date” also fails often. That date is a mean, so in about half of years frost comes later. Tatsoi and mizuna shrug this off. Young bok choy and Chinese broccoli seedlings that have been hardened off usually survive a light frost, but a hard frost can kill soft transplants.
Winter is the other fixed limit. The mean daily minimum of the coldest month at the Montreal reference station is -14.1 °C (6.7 °F). No common Asian green overwinters in an open bed at that level. Some mizuna and tatsoi may live through a mild stretch under snow, but you should not count on them. A cold frame or unheated tunnel can extend harvests into late fall and sometimes early winter, but it is season extension, not survival.
What goes wrong in a wet, humid stretch?
Heading types sown too close hold moisture in their centers, and the inner leaves can rot. Give bok choy and napa room between plants depending on the size of the type, and thin early. The other recurring problem is flea beetles. They pit the leaves of every brassica in spring, and seedlings under floating row cover from the day they are sown mostly escape them.
Weekly deep watering matters less than steady moisture. A dry spell followed by a soaking pushes mustard greens and bok choy toward bitterness and bolting. A thin mulch of straw or shredded leaves between rows holds moisture and slows weeds.
What changes across Quebec
Quebec is not one garden. Natural Resources Canada places the reference city in Canadian hardiness zone 5b, using its 1991-2020 normals. That is the Canadian system, built on seven climate variables, and it does not convert to a USDA zone. There is no single zone for the province. The range runs from the milder lowlands along the St. Lawrence to cold northern and upland districts that sit in far harsher zones.
The frost dates above come from the same reference area and from the 1981-2010 period. Northern and upland districts run weeks behind them. Gardens at altitude or far from the river can see frost arrive earlier in fall and hang on later in spring, which shortens the frost-free window noticeably.
If you garden north of the main farming belt or on higher ground, shift in three ways:
- Start the fast, hardy types (tatsoi, mizuna, komatsuna) as soon as the soil can be worked, and skip the slow ones in spring.
- Sow the fall crop earlier than the southern calendar suggests, so heads and leaves size up before hard frost.
- Use floating row cover or a cold frame to claim a few extra weeks at each end.
Do not take a zone from a neighbor or a nursery tag. Look up your own municipality on Natural Resources Canada’s plant hardiness map and read the zone it gives for your location. Then use the sowing timing in When to Sow Asian Greens in Quebec as a starting point, moving everything later in spring and earlier in fall if you are well north of Montreal.
Where to check this for your own county
The provincial agriculture ministry, MAPAQ, is the starting point for official guidance, and its regional offices connect to local growers and advisors. When you visit, look for two things. One is a local planting calendar for leafy brassicas and Asian vegetables, with sowing windows tied to your region’s frost dates. The other is any list of varieties trialled where you live, since a bok choy that performs in the lowlands can behave differently in a cooler valley.
Ask about bolting tolerance in particular. Variety differences matter most there, and local growers know which ones hold through a warm June. Ask also about flea beetle timing in your area, because the first flush of adults sets how early you need row cover.
A recommendation written for your own area beats a provincewide one. Provincewide advice, including everything above, is built from a reference station and an average of many climates. It gets the type of crop right and the exact dates only roughly. A county or regional calendar knows your frost pockets, your soil and your typical spring.
If you cannot reach an advisor, a local garden club, a regional seed company that grows and sells to your climate, or a nearby market gardener can give you the same ground-level information. Ask which Asian greens they sow in spring, which in August, and which they have stopped bothering with.
Checking this against your own garden
Your own observations outrank every date here. Three are worth watching, and none needs equipment.
First, feel the soil. Push your hand a few inches into the bed in the morning. If it feels cold and stays clammy, seed will sit and sulk, and hardy greens like mizuna germinate slowly. When the soil feels merely cool and crumbles, sow the fast types. A bed that warms days before the rest of the yard is a sheltered, sunny microclimate, which suits an early sowing. A bed that stays cold long after neighbors have planted is low, shaded or heavy, so you should wait.
Second, watch for the first true leaves. The first pair after the seed leaves is round and smooth, and the true leaves that follow have the shape of the mature plant. If they appear soon after emergence and seedlings stay compact, your timing and temperature are about right. If seedlings stretch, turn pale or send up a flower stalk early, you sowed into too much heat or too little light, and the next sowing should shift to a cooler window.
Third, note where frost lands first in fall. Walk the garden at dawn after the first cold night and see which beds are white and which are clear. Low spots collect cold air and frost first, while beds near a south wall or fence stay clear longer. That tells you where to put the last napa and bok choy and where to reserve space for the frost-hardy leaf types. Over a couple of seasons, that map will be more reliable than any average.
Common questions
Which Asian green is easiest to start with in Quebec?
Mizuna and tatsoi. Both germinate in cool soil, tolerate light frost, resist bolting better than most and can be cut young repeatedly. Bok choy is the next step up and rewards a little more attention to spacing and moisture.
Can I sow Asian greens in spring and again in fall?
Yes, and that is the standard approach. Sow the fast types as soon as the soil can be worked, then sow again in late summer for fall harvest. Skip midsummer sowings of heading types, which bolt in heat and long days.
Is napa cabbage worth the trouble?
As a fall crop, yes. It needs cool weather to form a tight head, so it should be sown in summer and harvested before hard freezes. In spring it is likely to bolt before heading, so it is not worth the space then.
Will any Asian greens survive a Quebec winter outdoors?
Not reliably in an open bed. The mean daily minimum of the coldest month is -14.1 °C (6.7 °F) at the Montreal reference station. A cold frame or tunnel can keep hardy types such as tatsoi and mizuna harvestable well into late fall, and sometimes beyond.