When to Sow Asian Greens in Texas

Sow Asian greens in Texas mainly from fall through winter, with a shorter second window in late winter. Around Houston that runs from late September into February, and spring sowing is over by early March. Texas is too big for one calendar, though. The Panhandle and the Gulf Coast sit months apart, so the dates below are a starting point to adjust.

The short answer for Texas

For Houston, the reference point used here, sow most Asian greens from late September through February. A last round of quick baby-leaf crops can go in during early March. Fall is the main season because the crops mature as days shorten and nights cool. Spring sowing works only while the weather is still cool.

The frost dates explain the timing. At the Houston Bush Intercontinental station (IAH), NOAA’s 1991-2020 Climate Normals put the last spring 32°F freeze between February 4 and March 1. They put the first fall freeze between December 1 and December 19. Those dates are probabilities of a 32°F freeze, taken from the 30-70% band. Early in each range, a freeze is still fairly likely. By the end of the range, it has become unlikely.

The coldest month at that station has a mean daily minimum of 43.7°F. That is the average night low, not the record low, so a hard freeze can still arrive. Most winters, though, are mild enough for hardy Asian greens to keep growing. Hobby airport on the other side of Houston runs about two weeks milder than IAH, so the dates shift even within the city.

When should you sow Asian greens in fall?

Start in late September or October with fast leaf crops such as mizuna, tatsoi and baby bok choy. They sprout quickly and tolerate the warm soil that still lingers. From October through November, sow everything, including larger bok choy, komatsuna and mustard greens. Sow directly in the ground and thin as they grow. The days to harvest on a seed packet count from sowing.

Can you sow Asian greens in spring in Texas?

Yes, but the window is short. Sow hardy leafy types from late January through February, then stop except for quick baby-leaf crops. Waiting for the last frost to pass, the usual advice in colder states, puts seedlings into warming weather too late. Lengthening days and rising heat push Asian greens to bolt, meaning they send up a flower stalk and turn bitter.

For crop choices that suit each window, see The Best Asian Greens for Texas. The wider overview is in Growing Asian Greens in Texas.

What will not work here

Summer sowing fails. Houston’s cold-month nights average 43.7°F, which tells you how early warmth returns. By the time the last spring freeze has passed (between February 4 and March 1), the cool season is nearly spent. A bok choy seedling started in May or June bolts before it makes a usable plant. Wait for fall.

The northern rule of sowing after the last frost also fails. In colder states, that rule makes sense. Along the Gulf, the last freeze comes so early that “after the last frost” lands in a month when the weather is already turning warm. Sow in late January or February, before the window has closed, and be ready to cover seedlings if a freeze is forecast.

Sowing too early in fall backfires as well. Late summer and early fall stay hot, and seed sown in a warm bed either sprouts poorly or bolts as it matures. Many gardeners in the northern states sow fall greens in August, and copying that calendar in Houston puts the crop into heat it cannot handle. Watch the forecast and start when the soil has cooled enough for the crop you are sowing.

Weekly watering will not carry a seedling bed through a hot, dry spell. Shallow-rooted greens dry out between waterings, and seed that dries after sprouting is lost. Sow in a spot where the soil stays evenly damp, or water lightly more often until true leaves form. Mulch helps hold moisture without crowding the plants.

Close spacing is a problem in Gulf humidity. Packed leaves stay wet after rain and dew, and fungal diseases and slugs follow. Thin seedlings to the spacing on the seed packet, and give heading types, such as full-size bok choy, room for air to move. Caterpillars and flea beetles stay active through fall and often attack tender young leaves. A lightweight row cover over the bed blocks both pests.

Slow, heading types, such as napa cabbage, also need care. Sown late, they run out of cool weather before the head forms. Choose quick varieties for late sowings and keep slower types to the early part of the fall window.

What changes across Texas

Texas spans USDA hardiness zones 6a to 10a, according to the 2023 USDA Plant Hardiness Zone Map. Gardeners in the northern high country face winters much colder than those on the Gulf, so there is no single answer for the state. The zone is built on one variable, the average annual extreme minimum temperature. It does not capture summer heat or the exact frost dates.

Houston is the mild Gulf end of that range. The Panhandle freezes months earlier in fall and months later in spring. Hill Country and North Texas fall somewhere between the two and differ from each other as well.

For gardeners in the north or at altitude, the shift is large. Fall sowing moves earlier so plants can size up before the first hard freeze arrives. Spring sowing moves later, because the last freeze comes later. The cool window is narrower, which favors quick baby-leaf crops over larger heading types. Winter growing needs cover or a cold frame, since a hard freeze can kill seedlings that a Houston winter would spare.

Gardeners nearer the Gulf have the opposite situation. For them, winter is the main growing season, and the risk is early spring heat rather than cold. Sow earlier and plan to harvest before warm weather arrives.

Look up your own zone on the USDA Plant Hardiness Zone Map rather than guessing from a neighbor or a nursery tag. Two places in the same zone can still have different frost dates, so treat the zone as a rough guide, not a calendar.

Where to check this for your own county

Texas A&M AgriLife Extension is the place to go. Every county has an office, and the staff there know local soil, frost patterns and pests. A county recommendation beats a state one, and any statewide calendar, Houston’s included, only gets you started.

When you search the site or call the office, ask for these things:

• The local vegetable planting calendar for your county, which lists cool-season crops and the dates to sow them.
• The vegetable varieties trialled in your county, since a variety that thrives on the coast may bolt in the hills.
• The typical first and last freeze dates for your area.
• Any local notes on pests, such as caterpillars and flea beetles on brassicas.

County offices often run Master Gardener programs. Volunteers there can tell you what has worked in nearby gardens this year, which no published calendar captures. Ask whether any local trials included bok choy, mustard greens or other Asian greens, because results from a few miles away are worth more than a statewide average.

Keep the Houston dates handy while you check. They show how the pieces fit: sow before the last freeze window closes in spring, and get fall sowings started with enough time to mature before the first freeze window opens. Your county numbers will move those dates, but the logic stays the same.

Checking this against your own garden

Your own observations outrank every date here. A garden on a south-facing wall behaves differently from one in a low, shaded corner, and three simple checks will show you how yours behaves.

Soil warmth by feel. Push your hand into the top inch of the bed in the morning. In early fall, soil that still feels warm will make seedlings bolt, so wait until it feels cool and damp. In spring, once it feels warm by midmorning, the window for sowing is closing. A bed that warms early is a sunny, sheltered spot, so sow that one first in fall and last in spring.

First true leaves. Seedlings first show seed leaves, and the first true leaves follow. If the true leaves come quickly and the plants stay compact, your timing is working. If seedlings stretch tall and pale or bolt early, the bed is too warm or too shaded for that sowing date. Move the next round later in fall or earlier in winter.

Where frost shows up first. On a cold morning, look at which parts of the yard are white. Low spots collect cold air and frost earlier, while beds near a house wall or fence stay a few degrees warmer. That pattern tells you which beds need cover first and which can go without.

Common questions

Can you grow Asian greens in Texas in summer?

Mostly no. Heat makes them bolt quickly, and the leaves turn bitter. Wait until fall, when nights cool down, and sow then. Gardeners in the northern high country have a longer cool season in summer, but it is still short.

How late can you sow Asian greens in fall near Houston?

Into late fall for most types. The first fall freeze falls between December 1 and December 19 at the IAH station, and many Asian greens tolerate light frost. Quick baby-leaf crops sown in November are usually ready before a hard freeze. Cover beds on nights when a hard freeze is forecast.

Should you start Asian greens indoors or sow directly?

Most are sown directly in the ground, which suits quick leaf crops. Starting seedlings in trays helps only when you want to get a head start during a warm spell. Seedlings in trays can sit in shade until the bed cools. Either way, the days to harvest on the packet count from sowing for direct-sown crops.

Does the Houston calendar work for Dallas or San Antonio?

Not exactly. North Texas has an earlier fall freeze and a later last freeze, so the cool-season window is shorter and shifted. San Antonio and the Hill Country differ again. Use your county extension office for local dates. Even within Houston, Hobby airport runs about two weeks milder than IAH, so a gardener there can sow a little later in fall and start a little earlier in winter.