Kentucky gardeners get two windows for Asian greens: early spring, around the last frost, and late summer into fall, counted back from the first freeze. Midsummer is the gap. The dates below come from Louisville’s 1991-2020 climate normals, so they shift with your location. For the full crop overview, start with Growing Asian Greens in Kentucky.
The short answer for Kentucky
Sow Asian greens in Kentucky in early spring, starting right around the last frost, and again in late summer so the crop finishes before the first hard freeze. Skip midsummer. That is the whole calendar, and the frost dates explain where its edges fall.
For the reference station at Louisville, NOAA’s 1991-2020 Climate Normals put the last spring frost at March 24 to April 4, and the first fall frost at November 2 to November 12. Those ranges are probabilities, not promises. Each one marks the stretch of dates when the chance of a 32°F freeze sits between 30 and 70 percent. Inside the spring band, a freeze is close to a coin flip. After it, a freeze gets less likely, but nothing in the data makes it impossible.
That is why the spring window opens before the band, not after it. Tatsoi, mizuna and bok choy are cool-weather crops, and a seedling that goes in as the soil becomes workable has weeks of mild weather to put on leaves before the heat arrives. Sow in small batches through the band and into April, and keep a sheet of row cover handy for the nights when the forecast drops to freezing.
Fall works in reverse. Pick the November 2 to 12 band as your finish line and count backward, so plants are well grown when the first freezes arrive. The cooling nights of late summer and early fall are what these crops want, and a fall sowing rarely bolts the way a late spring one does. The earlier sections of the calendar below put numbers on the anchors, using only the dates NOAA supplies.
| Window | Anchor from the frost dates | What to do |
|---|---|---|
| Early spring | Last spring frost: March 24 to April 4 | Start sowing the hardiest types as soil can be worked, then sow in small batches through April. Cover on freezing nights. |
| Midsummer | Between the two frost bands | Mostly skip. Heat, bolting and pests win. |
| Late summer to early fall | First fall frost: November 2 to November 12 | Sow so plants are established well before the band. |
| Winter | Coldest-month mean daily minimum: 27.8°F | Treat as covered growing only, with no guarantees. |
One caution comes attached to the Louisville numbers. The National Weather Service in Louisville warns that this urban station runs later in spring and earlier in fall than the rural countryside around it. a farm or an exposed lot in Jefferson County should expect a tighter window than the one above.
What will not work here
Length of season is not Kentucky’s problem. From the late end of the spring band (April 4) to the early end of the fall band (November 2) there are roughly seven months, which is plenty for fast leafy crops. The trouble is where the heat falls inside those months, and four habits tend to fail.
The first is sowing in May and expecting a spring harvest. By then the days are long and the weather is warming, and bok choy and its relatives respond by sending up flower stalks before the heads fill out. The crop is not dead, but the leaves turn bitter and the useful part of the plant is gone. Sowings that come after mid spring are a gamble. The ones that work are in the ground early enough to be eaten before that switch flips.
The second is planting in open ground through midsummer. Kentucky summers are humid, and humidity changes how you should space a crop. Tight rows of baby greens stay damp, hold leaf diseases, and shelter slugs. Heat adds flea beetles, which turn tender leaves into lace. A bed thinned for airflow does better than a dense one, and in July and August even a well-spaced bed often loses to the weather. If you want help choosing types that stand heat or resist bolting better, The Best Asian Greens for Kentucky sorts them by type.
The third is counting on winter survival. The mean daily minimum of the coldest month at Louisville is 27.8°F. That is an average, so an ordinary winter night is already below freezing, and the colder nights sit below the average. Tender bok choy will not carry through uncovered. Tatsoi and mizuna are tougher and can come through under a low tunnel or heavy row cover in a mild winter, but treat anything that survives as a bonus, not a plan.
The fourth is reading the frost dates as a guarantee. A band of 30 to 70 percent says a freeze can still arrive after you have planted. Seedlings of cold-tender types need cover for that. Copying Louisville’s dates straight into a rural bed without adjusting for the warmer-city effect is a related error. Out in the country, the last spring freeze tends to land later and the first fall freeze earlier, so the safe sowing window is shorter at both ends.
What changes across Kentucky
Kentucky is not one garden. The USDA Plant Hardiness Zone Map (2023 edition, built on 1991-2020 normals) places the state in zones 6a to 7a, which is a spread of one full zone. There is no single answer for the whole state, and the Louisville dates here describe one place, not all of it.
The zone system rests on one variable: the average annual extreme minimum temperature. It tells you how cold the worst nights get, which matters for overwintering, but it says nothing directly about when the last spring frost comes or how long the growing season runs. For sowing dates, use the frost bands. For deciding whether anything might live through winter, use the zone.
The direction of the shift is easy to state. A garden in a colder part of the state, in the north along the Ohio River valley’s higher ground, or in the eastern hills at elevation, should push spring sowing later and pull fall sowing earlier, both from the Louisville numbers. A warmer garden can lean the other way. I won’t give a day count, because the data on this page does not support one, and a made-up adjustment would be worse than none.
Terrain matters too. Cold air pools in low spots and river bottoms, so two gardens a mile apart can see their last frost days or weeks apart. A south-facing slope or a spot against a house wall warms sooner. Those local differences can be as large as the gap between zones.
Which zone you are in is something to check, not to guess. Look up your location on the USDA Plant Hardiness Zone Map and read the zone for your own address.
Where to check this for your own county
The best next step is University of Kentucky Cooperative Extension, the state’s land-grant extension service. Every county has an extension office, and the agents there know the local frost patterns, the soils, and which pests are showing up this year.
Two things are worth looking for. The first is the local planting calendar or vegetable planting guide, which usually lists dates for cool-season crops by region. If it covers Chinese cabbage, bok choy or similar crops, use those dates over mine. The second is any variety trial data from your area: which cultivars were grown nearby, how they handled heat, and which bolted. Trial results from your own county beat any general list, because they come from conditions like yours.
A county recommendation outranks a state one. This page is the state one. It rests on a single reference station in Louisville, plus a hardiness range that covers the whole state, and it has no county-level planting dates. Where an extension recommendation and this calendar disagree, trust the extension office.
If you cannot find a leafy-greens calendar online, call or visit the county office. Ask what the typical last spring frost is for your part of the county, and whether fall frost has tended to come early in recent years. Those two answers will let you move the Louisville bands to fit your own ground.
Checking this against your own garden
Your own observations outrank every date above. The calendar gets you to the right month, and the garden tells you the right week. Three signals are worth watching, and none needs equipment.
Soil warmth by feel. Push a hand into the bed in the morning. If the soil feels cold and clammy and stays that way for a minute, seeds will sit and may rot. Cool-season greens tolerate cold soil better than most crops, but they still need it workable and not soggy. A bed that thaws and drains first is your early-spring bed. One that stays cold a week longer tells you where not to sow first.
The first flush of male flowers. Watch for the dangling male catkins on a hazel or birch, if you have one nearby, or the first blooms on the early flowering trees in your yard. Plants register warmth over weeks and not just on one mild afternoon, so a tree that flowers early compared with the same species down the road points to a warm pocket, and one that lags points to a cold one.
The first true leaves. The first two seed leaves are not the real thing. Once the true leaves appear, the seedling has established. If you sow a succession, note how long each batch takes to reach that stage. In a cool, shaded corner it takes longer than against a sunny wall, and that difference is your microclimate measuring itself. In fall, true leaves that arrive before cold nights mean you sowed in time. If they haven’t, the plant is already behind the frost band.
Common questions
Can I sow Asian greens in July in Kentucky?
You can, but results are poor in open ground because of heat, bolting and pests. A better plan is to wait until late summer and count back from the November 2 to 12 first-frost band, sowing in cooler weather.
Do Asian greens survive Kentucky winters?
Not reliably. The coldest month’s mean daily minimum is 27.8°F, so nights below freezing are the norm. The hardier types may survive under row cover or a low tunnel, but plan on a harvest before winter.
Is the March 24 to April 4 date a safe sowing date?
It is the last spring frost band, meaning a 30 to 70 percent chance of a 32°F freeze. Hardy greens can go in before it, with cover for cold nights. Tender seedlings should wait until the odds of a freeze drop.
Do these dates apply to my county?
Only roughly. They come from the Louisville reference station, which runs warmer than the countryside around it, and Kentucky spans zones 6a to 7a. Check with your county extension office for local dates.