Sow Asian greens twice: in late winter to early spring, and again from late summer into fall. Midsummer is the dead zone, when heat and long days send most of them to seed. Bok choy, mizuna, tatsoi and the mustards all follow this rhythm. The dates slide by several weeks between the Tidewater coast and the mountains, so the coast is only the starting point.
The short answer for Virginia
Sow cool-season Asian greens from late winter through early spring, then again from late summer through fall. The best-documented frost dates come from the coastal reference station at NAS Oceana in Virginia Beach, which sits at the mild end of the state. There, the last spring freeze falls between March 20 and April 3, and the first fall freeze between November 10 and November 24.
These dates are probabilities of a 32°F freeze. NOAA’s 1991-2020 Climate Normals give the band where the odds sit between 30 and 70 percent. A freeze can still arrive before or after the window, and a mild spring can fool you into thinking the danger has passed. Greens tolerate a light frost better than most garden crops, which is why they can go in the ground before those dates rather than after them.
When do you sow Asian greens in spring?
Start as soon as the soil can be worked without turning to mud. On the coast that usually means late winter into early spring. Inland and at higher elevations it shifts to March and into April. Mizuna, tatsoi, komatsuna and mustard greens handle the cold well as seedlings. Bok choy is touchier, since a long stretch of cold right after sprouting can trigger early flowering. Cover it on the coldest nights.
Make small sowings every couple of weeks rather than one big one. Spring has a short runway, and each sowing matures a bit faster than the last as days warm up. Stop sowing when daytime heat settles in, earlier on the coast and a little later in the cooler uplands.
When do you sow Asian greens in fall?
Fall is the better season. Sow in late summer on the coast, and a few weeks earlier in the mountains. Plants grow into shortening days and cooling nights, so they stay leafy instead of bolting, and flavor sweetens after a few light frosts. On the coast, the first freeze lands in the second half of November, which leaves a long harvest runway for anything sown by early fall.
Winter is a real option on the coast. The mean daily minimum of the coldest month at Virginia Beach is 31.6°F. That is an average, so single nights run colder, but hardy greens under row cover often carry through. For help choosing types, see The Best Asian Greens for Virginia. The broader picture is in Growing Asian Greens in Virginia.
What will not work here
Sowing in May or June for a summer harvest fails almost every time. Summers across the state are hot and humid, and long days push bok choy, napa cabbage and most mustards to throw up flower stalks before they size up. The leaves turn bitter and tough. If you want greens in July, grow heat-tolerant leaf crops instead, such as amaranth or water spinach, and save the brassicas for cooler months.
Why do spring sowings get caught by the heat?
The spring window is short, and a late start eats it. A sowing made in mid-April at the coast has only a few weeks before warm weather arrives. Slow types like napa cabbage and large heading bok choy need a long, cool stretch to form dense heads. In spring they usually run out of time. Choose fast, loose-leaf types for spring and leave the heading types for fall.
Does close spacing work in a humid climate?
Crowded rows hold moisture on the leaves, and that invites downy mildew, leaf spot and slugs. Humid summers and damp autumns across Virginia make this worse than in drier parts of the country. Thin seedlings early, give each plant room for air to move, and water at the base in the morning so foliage dries by evening. Baby leaf crops cut young can be sown thick. Full-size heads cannot.
Insects press hard in early fall. Flea beetles chew small holes in mustard family leaves, and cabbage worms show up on warm days. Row cover laid right after sowing keeps both off, and it also adds a little frost protection later. Skipping it is the most common reason a fall planting looks ragged.
What happens if you copy the coastal dates in the mountains?
The Blue Ridge and southwest Virginia run weeks later in spring and earlier in fall than the coastal station. A gardener at altitude who follows the March 20 to April 3 window will lose seedlings to a freeze that the coast never sees. The same gardener sowing for fall in mid-September may find the first freeze arriving before heads have formed. Both mistakes come from using the mildest corner of the state as the template.
What changes across Virginia
The state is not one garden. The USDA Plant Hardiness Zone Map (2023 edition, built on 1991-2020 normals) places Virginia anywhere from zone 5a to 8b. That is a spread of several zones, from high ridges in the west to the warm coast in the southeast. No single answer fits that range, and a recommendation for one corner can be wrong by a month in another.
The zone number comes from one variable, the average annual extreme minimum temperature. It tells you how cold the worst winter nights get, which matters if you want greens to overwinter. It says much less about when the last spring freeze happens. Two gardens in the same zone can differ by weeks in their frost dates because of elevation, slope and cold air pooling in low spots.
How should northern and mountain gardeners shift the calendar?
Push spring sowing later, often by several weeks, and bring fall sowing earlier. In practice that means starting the fall sowing in August in the cold uplands, when it is still warm enough for seeds to sprout. Choose faster-maturing types, and plan on row cover or a low tunnel to stretch the harvest past the first hard freeze. Valley floors collect cold air on clear nights, so a garden low on a slope may frost while one higher up stays clear.
Look up your own zone on the USDA Plant Hardiness Zone Map rather than guessing from a neighbor. The map lets you enter a ZIP code and shows the zone for that exact area. Treat it as a guide to winter hardiness, and use local frost records to set sowing dates.
Where to check this for your own county
Your state extension service can tell you what works near you. Virginia Cooperative Extension has local offices that serve each county and city. Start there before you buy seed in bulk.
What should you look for on the extension site?
Look for two things. The first is a local planting calendar for vegetables, ideally one built around the average first and last frost dates for your county. Cool-season crops like Asian greens are usually listed with spring and fall sowing windows. The second is a list of varieties tested in your area, since a variety that bolts in coastal heat may do fine at altitude, and the reverse is also true.
Checking this against your own garden
Your own observations outrank any date in print. A calendar built from a weather station miles away cannot see the cold pocket behind your shed or the south-facing wall that warms early. Three simple things to watch will tell you more about your microclimate than a map can.
What should you watch in the garden?
The first is soil warmth by feel. Press your bare hand flat on the bed in the morning. If the soil is workable, crumbles in your fist and does not feel icy, it is ready for hardy greens. A bed that stays cold and wet weeks after a neighbor’s has warmed tells you your garden runs cool, and your sowing dates should shift later.
The second is the first true leaves. After sprouting, seedlings put out two round seed leaves, then the first leaves that look like the mature plant. If that takes much longer than a seed packet suggests, soil or air is cooler than you assumed. If seedlings leap ahead, you have a warm spot and can sow earlier next year.
The third is the first flower stalk. Watch an early sowing for a central stem pushing up from the middle. A stalk showing in a bed that was sown on time means heat or day length arrived sooner there than the calendar predicted. Write the date down and sow earlier the following spring, or move the crop to partial shade.
Common questions
Can you grow Asian greens through winter in Virginia?
On the coast, often yes. The mean daily minimum of the coldest month at Virginia Beach is 31.6°F, so hardy types such as tatsoi, mizuna and mustard greens can stand through winter, especially under row cover. Inland and in the mountains, expect to protect them with a tunnel or harvest them before deep cold.
Is spring or fall better for sowing Asian greens?
Fall is more forgiving. Plants grow as days shorten and nights cool, so they bolt less and taste sweeter. Spring works too, but the window is short and heat can arrive before heading types are ready. Choose fast loose-leaf varieties in spring.
Can you sow Asian greens in summer?
Summer sowing of bok choy, napa cabbage and mustard usually ends in bolting, bitter leaves and heavy insect pressure. If you want to sow at the very end of summer for fall harvest, do it as soon as the worst heat breaks, and keep the seedbed moist and shaded until sprouts emerge.
How do I know my own last frost date?
The coastal range of March 20 to April 3 does not apply everywhere. Check with your county extension office for local frost records, and use your own garden’s behavior as a check. A bed that thaws and warms late tells you to wait, even when the calendar says go.