Sow Asian greens in Missouri twice a year: in early spring, around the average last freeze of April 6 to April 20, and again in late summer, so the crop is established before the first fall freeze of October 18 to October 29. Both ranges come from the Kansas City airport station. Your own week will shift with your location.
The short answer for Missouri
Start the hardy, fast crops outdoors as soon as the soil can be worked in late winter or early spring, and sow the main fall crop from late summer onward. The frost dates are the frame for both windows. They are not the starting gun.
What the frost dates actually measure
Each date is a probability, not a deadline. NOAA’s 1991-2020 Climate Normals give the dates when the chance of a 32°F freeze falls in a 30% to 70% band. In spring, that band runs April 6 to April 20. In fall, it runs October 18 to October 29. Inside the spring range, a freeze is still close to a coin flip. That is why a lot of gardeners get burned by planting on “the last frost date.” You can read the underlying station data in the NOAA NCEI normals file.
| Marker | Missouri figure (Kansas City reference) | What it means for sowing |
|---|---|---|
| Last spring freeze (30-70% band) | April 6 to April 20 | Hardy greens can go in around and before this range; tender transplants should wait for the later end |
| First fall freeze (30-70% band) | October 18 to October 29 | Count backward from here for fall sowings |
| Mean daily minimum, coldest month | 19.5°F | Winter is cold enough to end most uncovered crops |
Reading the window
Spring is the shorter opportunity. Cool-season greens like to mature before the heat arrives, so sow early and treat any hot spell as the end of the season. Fall is the more forgiving window, because the days cool as the crop grows instead of warming against it. Most gardeners who struggle with these crops in Missouri are fighting the calendar in spring and winning in fall.
One caution on the reference point. The airport station sits well north of the city. Downtown typically runs about five days earlier in spring, and southern Missouri is milder still. Shift your spring dates earlier the farther south you garden, and do the reverse in fall.
For the full picture on crop choice and bed prep, start with Growing Asian Greens in Missouri. For help matching a crop to a window, see The Best Asian Greens for Missouri.
What will not work here
The spring freeze band is the first trap. A sowing date that looks safe in a table can still fall on a freeze, because the range is a 30% to 70% chance, not a zero. Tender seedlings set out on April 6 can be killed by a night at 32°F, and the odds are about even that one arrives. Hardy leaf crops shrug it off. Seedlings that have not hardened off do not.
Late spring and summer sowings
Sowing heading types in May or June is the second failure. By then Missouri’s heat and lengthening days push cool-season greens to bolt, sending up flower stalks before the plant has made a harvest. Bok choy and mizuna that should have given a month of cutting turn bitter and tall. No watering routine fixes this, because the trigger is heat and day length, not thirst. The Missouri summer is also humid, which makes crowded plants a bigger risk. Close spacing that works in a dry climate holds moisture in the canopy here, and the result is leaf spots and rot. Give plants room and water the soil, not the leaves.
Waiting too long in fall
The third failure is the late fall sowing. Count backward from October 18 to October 29, the first-freeze band. A seed sown close to that date has almost no growing time, and growth slows sharply as nights cool. You end up with seedlings that never size up. The sowings that pay off are the ones made in late summer, when soil is still warm enough to germinate fast and the plant has weeks of mild weather ahead.
Expecting winter survival
The fourth is assuming a crop will overwinter bare. The coldest month’s mean daily minimum at the Kansas City reference station is 19.5°F. That is an average night, not a record low, so many nights run colder. Tender Asian greens do not sit through that uncovered. If you want a winter harvest, plan on a cold frame, row cover, or a low tunnel, and treat anything that survives in the open as a bonus. This page does not have trial data on which varieties hold up best, so I won’t claim any do.
What changes across Missouri
Missouri is not one garden. The USDA Plant Hardiness Zone Map (2023, built on 1991-2020 normals) places the state across zones 5b to 7b. That is a spread of several zones, so there is no single answer for the whole state. Remember also that the USDA system rests on one variable, the average annual extreme minimum temperature. It tells you about winter cold, not about spring frost timing or summer heat.
If you garden in the north
Northern Missouri sits at the colder end of that range. Nights stay cold longer in spring and return sooner in fall. Expect the spring window to open later than the Kansas City figures suggest, and the fall deadline to arrive earlier. Sow your fall crop on the early side of late summer, and keep row cover on hand for the first hard nights.
If you garden in the south or at higher elevation
The south is milder, as the frost data note. Spring opens earlier and fall lasts longer, which gives you more room to sow a second or third round. The same warmth pushes heat stress earlier, so the spring crop has less time before bolting weather. Higher ground, such as hills and ridges, can behave more like a colder zone than its surroundings, and low pockets collect cold air on still nights. Those microclimates can move a bed’s frost date by days.
I won’t tell you which zone you are in. Look up your address on the USDA Plant Hardiness Zone Map and compare it with the Kansas City reference. If you land colder, shift your dates later in spring and earlier in fall. If you land milder, do the opposite.
Where to check this for your own county
Your state extension service is the next stop. University of Missouri Extension runs county offices across the state, and their staff know local conditions that no statewide table can capture. Look for two things there: the local planting calendar for your county and any vegetable varieties that have been trialled near you.
A county recommendation beats a state one. Frost dates, soil, and elevation can differ enough within a short drive to change when you should sow. This page is the state-level view, built from the Kansas City reference station and the statewide hardiness range. It is a starting point, not a final answer for your garden.
A note on what this page does not have. The facts here include no Missouri-specific extension calendar for Asian greens. The extension calendars on file for this page are Clemson Cooperative Extension lawn guides, which cover tall fescue, bermudagrass and zoysiagrass in South Carolina. They are not relevant to leafy vegetables in Missouri, so I have not used them. If a Missouri county office has a vegetable calendar or a variety trial report, it will serve you better.
When you contact an office, bring your town, a sense of whether your yard is on high ground or in a low spot, and the crops you want to grow. Ask when they recommend sowing for spring and fall, and which varieties have performed well in local conditions. Those two answers are worth more than any date printed here.
Checking this against your own garden
Your own observations outrank every date on this page. Three things are worth watching, and none requires equipment.
- Soil warmth by feel. Dig a handful from a few inches down in early spring. If it crumbles and feels cool but not icy, it is workable. If it clumps wet and cold in your fist, wait. A bed that warms sooner than your neighbor’s tells you it has good drainage or a sunny exposure.
- The first catkins. The male flowers on trees such as birch, hazel and oak loosen and shed pollen as spring settles in. Note when they appear near your yard each year. A tree in a sheltered spot will run ahead of one in an open, windy one, and the gap hints at how much your site holds heat.
- The first true leaves. Seedlings first show seed leaves, then the first true leaves. Watch how fast your earliest sowing gets there. Slow, pale growth means the soil or nights are still too cold. Quick, dark green growth means your bed is warm.
Write these dates down each year. After two or three seasons you will have a calendar that fits your own yard, and it will be more accurate than a statewide table.
Common questions
When is the last spring frost in Missouri?
At the Kansas City reference station, the 30% to 70% probability band for a 32°F freeze runs April 6 to April 20. Downtown runs about five days earlier, and southern Missouri is milder still.
When is the first fall frost in Missouri?
The same station shows October 18 to October 29 for the 30% to 70% band. Count backward from these dates when planning fall sowings, and expect earlier dates in the north.
Can Asian greens survive a Missouri winter outdoors?
Not reliably without protection. The coldest month’s mean daily minimum at the Kansas City reference station is 19.5°F. Use a cold frame, row cover or low tunnel if you want winter harvests.
Does one planting calendar work across all of Missouri?
No. The state spans USDA zones 5b to 7b, so dates shift between north and south. Use the Kansas City figures as a baseline and adjust with your county extension office.