In north Florida, plant sweet potato slips in spring once the last freeze has passed and the soil has warmed. Keep planting into early summer, as long as the crop can still be dug before fall cold. Central and south Florida run on a different clock, because frost barely matters there and summer is the hard season. Where your garden sits decides the date.
The short answer for Florida
For Jacksonville, the last spring frost falls between February 16 and March 7, and the first fall frost between November 26 and December 13. Both ranges come from NOAA’s 1991-2020 Climate Normals and describe the span where the odds of a 32°F freeze sit between 30 and 70 percent. They are probabilities of a freeze, calculated from thirty years of nights. Sweet potato slips are tender and a freeze kills them, so the first planting date comes after the spring range closes, not inside it.
Soil temperature sets the actual start. Slips set into cold, wet ground sit idle and can rot, so the practical date is a few weeks past the last frost range, when the ground holds warmth overnight. On the other end, the crop needs time to size up its roots before the fall range opens on November 26. That gives north Florida a planting window that begins in spring and stretches into early summer, with the later plantings squeezed against the first cold.
When do you plant sweet potatoes in north Florida?
Think spring through early summer. Plant when the soil is warm and there is a long runway before frost. A planting that goes in during the heat of summer can still work, but it leaves fewer weeks to fatten roots, and every week matters if cold arrives early. Cold does not always arrive: three of the thirty falls in the Jacksonville record saw no freeze at all. That is a reason to plan for the freeze, not to count on skipping it. Jacksonville’s airport is also an inland site, so a garden near the coast may stay frost-free longer.
Does the same window work in Orlando or Miami?
No. Central and south Florida are effectively frost-free, so the frost dates above do not apply there. The growing calendar inverts. The main season runs through winter, and summer is the hard part of the year. A gardener in Orlando or Miami who copies a north Florida spring calendar ends up planting into the most punishing months. The full picture for the state, from soil prep to harvest, is in Growing Sweet Potatoes in Florida.
What will not work here
Most failures in Florida come from a calendar borrowed from somewhere else. Gardeners in cooler states plant late in spring and harvest in early fall, and that rhythm fits a short season. Florida’s season is long, so variety speed is not the main concern. The problems are cold at the front end in the north, heat and water through the middle, and the wrong calendar altogether in the south.
Can you plant sweet potato slips before the last frost?
It is a gamble that rarely pays. Jacksonville’s last frost range runs from February 16 to March 7, and a warm spell in February can tempt a gardener to start. A single freeze after that kills exposed slips outright, and even without a freeze, cool soil keeps them from rooting. Waiting a few weeks costs very little. Slips planted into warm soil catch up with early ones fast.
Does Florida’s summer heat and rain cause problems?
Jacksonville averages 73.2 days a year at 90°F or more. That heat does not stop mature sweet potato vines, but it punishes freshly set slips. A transplant dropped into afternoon sun on a hot day wilts hard, so set slips late in the day and water them in until they root.
Rain is the second trap. Summer brings about 21.2 inches across June, July and August, out of 53.4 inches for the whole year. July is the driest of the three at 6.77 inches, with June at 7.6 and August at 6.88. That sounds like plenty, and on heavy clay it can be too much. A flat bed that holds water invites rot and cracked roots, so build ridges or raised rows and give the vines room.
On sandy soil the story flips. A sandy surface lets rain through within the day, and a summer thunderstorm often drops its water fast and runs off before soaking in. A grower on sand who waters once a week can watch vines dry out between storms even in a wet summer. Those rainfall numbers are normals for the Jacksonville airport over thirty years. A rain gauge on your own plot tells you what actually landed.
What happens if you plant too late in north Florida?
Roots need weeks of warm weather to bulk up. A planting that goes in very late in summer will run into the first fall frost range, which opens November 26, before the roots have sized up. Vines blackened by a freeze stop feeding the roots, and what is in the ground is what you get. In a year with no freeze, the late planting may do fine, which is exactly why it tempts people. Plan for the frost year.
The biggest mistake in the other direction is moving the north Florida calendar south. In central and south Florida, planting in the summer months puts slips into the hardest season of the year there.
What changes across Florida
Florida is not one garden. The USDA Plant Hardiness Zone Map (2023 edition, built on 1991-2020 normals) places the state across zones 8b to 11b. The system rests on a single variable, the average annual extreme minimum temperature. Four zones inside one state means there is no single planting date for Florida, and anyone who offers one is describing a particular part of it.
The north, where Jacksonville sits, is the cold end of that range. Freeze danger shapes both ends of the season there: the spring start waits on the last frost, and the fall harvest races the first one. Gardeners in the northern tier should hold off on spring planting until soil is warm and dig before the first hard freeze. The variety trade-offs are laid out in The Best Sweet Potatoes to Grow in Florida.
Farther south, the frost calendar stops mattering. Central and south Florida gardeners work from the inverted pattern: the main season runs through the cooler months, and summer’s heat and heavy rain are what they plan around. Elevation barely enters into it, since Florida is low and flat. Latitude and distance from the coast do most of the work, along with whether the soil is sand or clay.
To find your own zone, use the USDA Plant Hardiness Zone Map and look up your ZIP code. Keep in mind that a zone number reports winter cold only. It says nothing about summer heat or rainfall, which matter just as much for sweet potatoes.
Where to check this for your own county
Your county’s UF/IFAS Extension office is the best next stop. Your county has one, staffed by people who work with local soils and local weather. Two things are worth asking for. First, the local planting calendar for sweet potatoes, which will give dates fitted to your area. Second, the varieties that have been trialed in your county.
While you are there, ask how your local soil behaves and whether the office can help with a soil test. In Florida, soil type changes the watering schedule and the rot risk more than most gardeners expect.
A local recommendation beats a general one, every time. The dates here are the state-level view, anchored to Jacksonville’s weather record. They show the shape of the season, but a county agent knows whether your area runs warmer, wetter or sandier than that reference point, and can adjust accordingly.
Checking this against your own garden
Dates on a calendar are averages. Your yard has its own weather, and what you see there outranks every number above. Three observations cost nothing and tell you a lot.
- Soil warmth by feel. Push your hand into the bed in the morning, about as deep as your fingers reach. If the soil feels cool and damp, wait. If it feels mild, the slips will root. Beds against a south-facing wall warm sooner than low spots.
- New leaves on your slips. Slips set into good conditions put out fresh growth. If they sit with no new leaves, the soil is still too cold, or it is drying out faster than you are watering. Sandy beds usually point to the second.
- The first frost damage nearby. In the fall, watch where tender plants in your yard first show blackened leaves. Those low, open spots catch cold first, and a sweet potato bed there needs digging earlier than one tucked near the house.
Over a season or two, those three notes become your own calendar, tuned to your soil and your yard. Write the dates down each year. They will be more reliable than any state average, this one included.
If you follow the almanac, here is when to plant sweet potatoes by the moon. It is a tradition, not a proven method.
Common questions
Can you plant sweet potatoes in Florida in summer?
Yes, in north Florida a planting in early summer can still finish before fall frost, though it has less room than a spring planting. Water new slips until they root and mulch to hold moisture. In central and south Florida, summer is the hard season for the crop, so the main planting happens in the cooler months instead.
When is the last frost in north Florida?
At Jacksonville, the last spring frost falls between February 16 and March 7, based on the 30 to 70 percent probability range for a 32°F freeze from NOAA’s 1991-2020 normals. Planting waits until after that range closes and the soil has warmed.
Do central and south Florida gardeners need to worry about frost?
Rarely. Both regions are effectively frost-free, which is why their calendar runs differently, with the main season through winter and summer as the difficult stretch. The Jacksonville frost dates should never be applied to Orlando or Miami.
Does Florida’s rain rot sweet potatoes?
It can on heavy, poorly drained soil. Jacksonville gets about 21.2 inches over June, July and August, and clay holds that water for days. Planting on ridges and spacing vines generously helps. On sand, the opposite problem shows up, and vines may need more frequent watering despite the rain.