In north Florida, sweet potato slips go into the ground once the last freeze risk has passed and the soil has caught up. At Jacksonville, the last spring freeze lands in a window of February 16 to March 7. Farther south the rules flip: Orlando and Miami are effectively frost-free, so the main season runs through winter and summer becomes the hard part. Below: the north Florida calendar first, then heat, rain and the choice of type.
When the soil is warm enough in Florida
Start with the date. For Jacksonville, the NOAA NCEI 1991-2020 Climate Normals (station USW00013889, the airport) put the last spring 32F freeze in a window of February 16 to March 7, using the 30 to 70 percent probability band. A frost date is a probability, not a promise, and the later edge of that band still leaves room for one more cold snap. The station is an inland airport, so a garden near the coast or in a low frost pocket can run differently.
Frost is a proxy, and soil is the real gate
Sweet potatoes are tropical vines, grown from rooted cuttings called slips. A frost date tells you when killing cold stops. It says nothing about the temperature of the ground a slip is standing in. Soil is slow. It warms behind the air the way a cast-iron pan warms behind the burner, which means planting condition arrives after the frost risk ends, not alongside it. Slips set into cold, wet ground sulk, stall and sometimes rot.
The practical move is a soil thermometer pushed into the planting row, read in the morning after a cool night. Then compare it with the planting threshold your county extension office publishes. This page does not quote a number, because the local figure beats a generic one. A warm afternoon after a chilly night is not warm soil, and that is the trap in a Florida March, when the days can feel like May.
Central and south Florida run a different calendar
Everything above is north Florida. Central and south Florida are effectively frost-free, so there is no last-frost date to wait for, and the growing calendar inverts. The main season runs through winter, and summer is the hard part. Never apply the Jacksonville window to Orlando or Miami.
The state spans zones 8b to 11b on the USDA Plant Hardiness Zone Map (2023 edition, built on 1991-2020 normals). That system rests on one variable, the average annual extreme minimum temperature. A spread that wide is exactly why one statewide planting date would be wrong. Gardeners south of Jacksonville should get winter planting dates from their local extension office. The general handling of slips, from sprouting to setting out, is the same everywhere.
How long the season lasts here
Jacksonville’s first fall freeze lands between November 26 and December 13, from the same NOAA NCEI normals. Set that against the spring window and the arithmetic is generous. March 7 to November 26 is 264 days. February 16 to December 13 is 300. Counting the calendar straight across, that is 264 to 300 days between freezes.
The fall end is softer than it looks. At that airport, three of the thirty autumns in the record saw no freeze at all, so the band describes a typical year and not a guarantee.
What a window that long allows
A long window allows a second sowing. Plant a second batch of slips weeks after the first and the harvest spreads out, and a failed first set costs a replant instead of a season. A short window does the opposite. The first sowing is the only one, and gardeners have to decide whether transplanting is worth the root check, that inspection of the slip’s roots before it goes in, since every week lost to transplant shock is a week the season cannot spare. Here the slack forgives a slow start.
The succession sowing guide on this site covers how to space plantings. The constraint specific to sweet potatoes is the fall band. Take the days-to-harvest listed for the type you buy (from the seller or your extension office, not from this page), count back from November 26, and that is your last sensible planting date. Use the early edge, because the crop finishes on the crop’s schedule, not the calendar’s.
Dig ahead of a forecast freeze, not after it. Cold ground can injure roots, and that damage shows up later in storage. For a sense of how different a season can be, the Growing Sweet Potatoes in Nunavut page sits at the far end, where the question is whether the crop can be grown at all. Florida’s problem is the reverse: too much time, and then too much heat and water inside it.
Heat and water in Florida
Sweet potatoes want accumulated warmth, and warm nights as much as warm days. At the Jacksonville reference station, the 1991-2020 normals count 73.2 days a year reaching 90F or more. That is more than ten weeks of days at or above that mark. It is a station count, not a portrait of the whole state, and it measures heat load, not average summer temperature. In a humid climate the nights tend to hold that warmth, and that is what the crop is after.
Where days like that pile up, the crop is routine. Gardeners in cooler places turn it into a project of black plastic, raised ridges and an early type. In north Florida, ridges still help, but for drainage instead of heat. The heat itself is on your side until it becomes too much, which in central and south Florida happens in summer. Those regions have their own numbers, and these are not them.
Rain that arrives all at once
The same station records about 21.2 inches of rain across June, July and August, out of 53.4 inches for the year. That is close to 40 percent of the annual total in three months. Month by month it runs 7.6 inches in June, 6.77 in July (the driest of the three) and 6.88 in August. This is the normal that decides whether roots swell steadily or split, because sweet potatoes react badly to a long dry stretch followed by a soaking.
Those inches never read alone. On sand, which is common across Florida, rain drains through within the day, so a wet summer can still mean watering every second day. On clay, the same inch can sit for a week, and roots in waterlogged rows rot instead of swelling. Heat pushes evaporation up, and a single summer thunderstorm mostly runs off instead of soaking in. A wet and muggy season also favors foliage and soil diseases, the same pattern gardeners fight across the humid Gulf coast, as in Growing Sweet Potatoes in Louisiana.
These are normals for one airport over 1991-2020. They are not a forecast and not your garden, and a slope, a city or a rain shadow changes them. A rain gauge on your own plot settles it. Read it after each storm and water only when the gauge and the soil both say the roots are dry.
Which sweet potatoes suit Florida
Choose by type, and let the territory’s own numbers set the criteria. This page names no varieties, and that is the right answer, not a gap. The only recommendation that means anything is the list of varieties trialled locally, and this page does not have those trials. A name recalled from memory is worse than no name, because a variety that thrives in one state’s sandy plots can fail in another’s.
| What Florida’s facts show | What it favors |
|---|---|
| A long window between freezes (264 to 300 days at Jacksonville) | Full-season types are workable; the earliest types earn their place mainly for a second planting. |
| 73.2 days a year at 90F or more | Vigorous vining types that shade the ground, planted on ridges with airflow between rows. |
| About 21.2 inches of rain from June through August | Disease resistance as the first criterion, in well-drained rows. |
Of the three, humidity ranks first. Ask whether a type has resistance to the soil diseases and pests common in sandy Florida ground, such as root-knot nematodes, and put that ahead of flavor or flesh color. Resistance is a trait you can look up. Taste is a matter of opinion.
Then take the question to your county extension office, reachable through UF/IFAS Extension. Ask which types have been trialled in your county, what soil pests to test for, and what planting dates fit your zone.
One mislabel to clear up while choosing: a sweet potato is not a yam, and the supermarket label is wrong. It is also not a potato and not a nightshade, so it does not follow potato rotation rules, and a bed that grew tomatoes or potatoes is not a reason to skip it.
Common questions
Can I plant sweet potatoes in Florida in summer?
In north Florida, a later planting can fit inside the window, provided it finishes before the fall freeze band. Farther south, summer is the hard part, with heat and heavy rain working against a young slip, and the main season runs through winter. Local planting dates from your extension office settle it.
Does the Jacksonville frost date apply to Orlando or Miami?
No. Central and south Florida are effectively frost-free, so there is no last-frost date to wait for, and the calendar inverts. The February 16 to March 7 window is a north Florida figure, taken from one airport station.
How should I store sweet potatoes after harvest?
Cure them first, then keep them somewhere that stays above the cold-injury range. Never put sweet potatoes in a refrigerator or a cold cellar. Cold injury is irreversible, and it is the most common way a good home crop is ruined after harvest. Inspect roots regularly. A soft patch or a weeping spot ends the question, and a root that merely looks sound is not proof that it is safe to eat. The full curing walkthrough is in Growing Sweet Potatoes: Slips, Heat, and a Careful Cure.
What happens if a freeze comes after I plant?
A freeze kills the leaves and can chill the soil around young roots, which is why the frost band is treated as a probability, not a promise. If one is forecast after planting, cover the row or be ready to replant. The long window here makes a replant affordable.