Florida splits Asian greens into two camps. Bok choy, tatsoi, mizuna, komatsuna, choy sum and gai lan are cool-season crops, and in central and south Florida that means roughly fall through winter. Amaranth and sweet potato leaves carry the summer. Choose by season first and variety second, because a great variety planted in the wrong month will still fail.
The short answer for Florida
Match the type to the season. The cool-season brassicas (bok choy, tatsoi, mizuna, komatsuna, choy sum, gai lan, mustard greens) are Florida’s main crop, and the heat-loving leaf crops (amaranth, Okinawa spinach, sweet potato vines) cover the summer gap. Almost every variety named in a seed catalog fits one of those two groups.
The mechanism is simple. Cold is rarely the limit here. In the reference city of Jacksonville, the mean daily minimum of the coldest month is 42.9°F, which these greens tolerate easily. Heat is what ends the crop: warm weather and lengthening days push brassicas to bolt, and the leaves turn bitter or tough.
North Florida has a frost calendar, so use it carefully. At the Jacksonville airport station, NOAA’s 1991-2020 normals put the last spring freeze (32°F) between February 16 and March 7, and the first fall freeze between November 26 and December 13. Those are probabilities, not promises: the dates bracket the band where the odds of a 32°F freeze run between 30 and 70 percent. The airport is also an inland site, and three of thirty falls saw no freeze at all.
Do not apply that window to Orlando or Miami. Central and south Florida are effectively frost-free, so the calendar inverts there. Winter becomes the main season and summer becomes the hard part. For exact sowing windows, see When to Sow Asian Greens in Florida.
| Type | Examples | Best season in Florida | Main weakness |
|---|---|---|---|
| Cool-season brassicas | Bok choy, tatsoi, mizuna, komatsuna, mustards | Fall through early spring | Bolt and turn bitter in heat |
| Stem and flowering types | Gai lan, choy sum | Cool months, with winter the safest stretch | Heat shortens the harvest |
| Heat-tolerant leaf crops | Amaranth, Okinawa spinach, sweet potato leaves | Late spring through summer | Slow when nights are cool |
What will not work here
Napa cabbage heads and slow, large-framed brassicas are the usual casualties. They need a long, steady cool stretch to form dense heads, and Florida’s cool window is short and often interrupted by warm spells. Loose-leaf and baby types finish faster and forgive more. If you want napa, plant it at the very start of the cool season and expect smaller heads than the seed packet photo shows.
Spring sowing is the second trap. A gardener in north Florida who waits for the last frost window of February 16 to March 7 to pass, then sows bok choy, is sowing straight into rising heat. The plants hurry toward flowers before they make a worthwhile head. Sow in fall, or in late winter if you want a quick spring crop, and finish before the warmth arrives.
Summer brassicas are mostly a waste of seed in central and south Florida. With no real frost there, nothing stops the heat from running the show for months. Heat, heavy rain and humidity also invite fungal leaf spots, and flea beetles riddle the tender leaves of mizuna, arugula-type mustards and tatsoi. Floating row cover helps against the beetles. It does not help against the heat.
Humid air also punishes tight spacing. Florida’s wet season keeps leaves damp for hours, and a crowded bed of bok choy stays wet longer than a thinned one. Give plants room for air to move, water at the base in the morning, and expect rot where leaves overlap.
Water spinach (kangkong, ong choy) needs a warning. It grows happily in Florida’s heat, which is exactly the problem: it is a restricted invasive plant in the state, and growing it can be illegal. Check with your extension office before planting it. Amaranth, Okinawa spinach and sweet potato leaves are safer summer choices.
Sandy soil, common across much of the state, causes one more failure. It drains fast and holds few nutrients, so greens fed lightly and watered irregularly stall and turn bitter. Compost and steady moisture matter more here than almost any variety choice.
What changes across Florida
Florida is not one garden. The USDA Plant Hardiness Zone Map (2023 edition) puts the state in zones 8b through 11b, and that spread is wide enough that there is no single answer for the whole state. The USDA system is built on one variable, the average annual extreme minimum temperature, so it says how cold the worst night gets and nothing about summer heat or rain.
North Florida and the Panhandle
Here the cool season is real, with frosts and freezes. Cool-season greens can run from fall into spring, and a hard freeze can still burn tender leaves, especially toward the end of the spring frost window. Keep a frost cloth handy and plant a little earlier in fall than you would farther south. Some hardy greens, such as mustards and tatsoi, can shrug off a light freeze, but baby bok choy and gai lan are more sensitive.
Central and south Florida
Move south and the calendar flips. With frost essentially absent, winter is the productive season, and summer belongs to amaranth, Okinawa spinach and sweet potato leaves. Gardeners in the Keys or in far south Miami-Dade have a very short window for cool-season brassicas and should lean on the heat crops the rest of the year.
Zones will not tell you which side of that line you are on. Look up your location on the USDA Plant Hardiness Zone Map rather than guessing from the nearest big city. Microclimate matters too: coastal gardens tend to be milder, and inland low spots can be colder.
Where to check this for your own county
Your county office of the University of Florida IFAS Extension is the next stop. Every county has one, and the staff know which varieties actually grew in local soil, which pests are active this year, and what the local sowing windows are.
Look for two things in particular. First, the local planting calendar for leafy greens or Asian vegetables, which will list sowing months for your county instead of the state as a whole. Second, any variety trial results: lists of cultivars tested in nearby gardens or research plots, which tell you what bolted, what resisted disease, and what tasted good.
A county recommendation beats a state one, and this page is the state one. It sketches the shape of the year across a very long, very varied peninsula. It cannot tell you whether your sandy lot near the Gulf or your clay yard in the Panhandle behaves differently from the reference city of Jacksonville.
Ask about restricted plants while you are there, since water spinach is not the only plant with a regulatory catch in Florida. For a broader overview of the crop family, see Growing Asian Greens in Florida.
Checking this against your own garden
Dates are averages and your garden is a single location. Three observations outrank every window above.
- Soil warmth by feel. Push your hand into the bed in the morning. If the soil feels cool and damp, brassica seed will germinate well. If it feels warm even before the sun is up, the bed is too hot for bok choy and you are in amaranth territory. A bed that stays warm longer than your neighbor’s tells you about sun exposure and mulch.
- The first flush of flowers. Watch the first plants to bolt in spring, whether a stray mustard or a crowded bok choy. The week they send up flower stalks tells you when your cool season really ended this year, which is worth writing down for next year.
- The first true leaves. Seedlings that stall at the first true leaves, or grow thin and stretched, are telling you the bed is too hot, too shaded or too dry. Seedlings that thicken up quickly are in the right spot at the right time.
Keep a simple note of sowing date, first harvest and first bolting. After one season it becomes a calendar built for your own yard, and a more reliable guide than any statewide window.
Common questions
What is the easiest Asian green to grow in Florida?
Mustard greens and bok choy are the most forgiving in the cool season, since both grow quickly and tolerate cool nights well. For summer, amaranth is the easiest because it thrives in heat that would ruin the brassicas.
Can I grow bok choy in Florida summer?
Rarely with good results. Heat and long days push it to bolt, and humidity encourages leaf diseases. Save bok choy for fall through early spring and use heat-tolerant greens in summer.
Does the frost window apply to all of Florida?
No. The February 16 to March 7 last-freeze window and the November 26 to December 13 first-freeze window come from the Jacksonville airport station in north Florida. Central and south Florida are effectively frost-free, so do not apply those dates to Orlando or Miami.
Is water spinach safe to plant in Florida?
Check first. It grows vigorously in warm, wet conditions and is restricted in Florida as an invasive plant. Ask your county extension office before sowing it, and consider amaranth or sweet potato leaves instead.