Sow hardy unusual roots in Arkansas from mid to late March, and hold tender ones until after April 3. Those two dates come from different frost thresholds, and mixing them up is the most common way a season goes wrong. This page gives the dates as NOAA and the National Weather Service publish them, then covers what fails here, how much the state varies, and where to get a county-level answer.
The short answer for Arkansas
Sow frost-tolerant roots between March 12 and March 28, and plant frost-tender ones after April 3. The March window comes from NOAA’s 1991-2020 Climate Normals for the Little Rock reference station. The April 3 date is the 36°F light-frost date from the National Weather Service in Little Rock.
That March window is a probability, not a date on the calendar. NOAA’s figures describe a 32°F freeze, and the dates mark the 30-70% probability band for the last one in spring. Some years the final freeze comes before March 12. Other years it comes after March 28. The same logic applies in fall, where the first 32°F freeze falls between November 7 and November 20, and the 36°F date is October 31.
The two thresholds matter because plants do not all quit at 32°F. Tender roots can be damaged by a light frost before the thermometer reaches freezing, so they follow the tighter window of April 3 to October 31. Hardy roots follow the looser one.
| Task | Threshold | Date to work from |
|---|---|---|
| Spring sowing of hardy roots | 32°F freeze, 30-70% band | March 12 to March 28 |
| Spring planting of tender roots | 36°F light frost | After April 3 |
| Harvest deadline for tender roots | 36°F light frost | October 31 |
| First freeze for hardy roots in fall | 32°F freeze, 30-70% band | November 7 to November 20 |
Winter is the other half of the picture. The mean daily minimum of the coldest month at Little Rock is 30.9°F, so a typical January night sits right at the edge of freezing rather than deep below it. Roots that tolerate frost can stay in the ground well past the first freeze, and the table above does not set a hard stop for them.
Which crops fall into which column is a separate question, covered in The Best Unusual Roots to Grow in Arkansas. For the wider overview of the category, start with Growing Unusual Root Crops in Arkansas.
What will not work here
Planting tender roots on the March dates is the first failure. The window of March 12 to March 28 is a 32°F window, and it closes about a week or more before the April 3 light-frost date that tender plants need. A gardener who sees a mild stretch in mid-March and sets out tender roots is betting against a frost that, by the numbers, can still arrive.
Starting tender roots late is the opposite mistake. The tender season runs only from April 3 to October 31, and a root that needs the whole stretch to size up has little slack. Every week you wait in spring comes out of the end of that window. Count back from October 31 using the days to maturity on the seed packet, because this page does not carry maturity figures for individual crops.
Seed packets written for northern gardeners cause a quieter problem. Many unusual roots are described as “sow in May” for cold-climate gardens. In Arkansas, May is when a hardy root is already running out of cool weather. This page does not have summer temperature or rainfall figures, but Arkansas summers are hot and humid, and a cool-season root sown late tends to stall or bolt instead of bulking up. Sow it in the March window or leave it for fall.
Humidity punishes close spacing. Foliage that stays wet after a warm night is an invitation to leaf disease, and a tight row of roots keeps the air from moving. Give each plant the wider end of the spacing range on the packet, and thin early.
Expecting a hard winter to do the work is another miss. With a coldest-month minimum of 30.9°F, Little Rock winters will not reliably chill or sweeten roots the way a northern freeze-up does, and they also will not kill the hardy ones. Lifting every root before Thanksgiving out of fear of winter is unnecessary. Mulch and leave them.
The last failure is using one threshold for everything. The 32°F dates are generous. The 36°F dates are the ones a tender plant actually answers to. Pick the right column for the crop.
What changes across Arkansas
Arkansas is not one garden. The USDA Plant Hardiness Zone Map (2023, built on 1991-2020 normals) places the state in zones 6b to 8a. That is a range, not a single answer, and it spans four half-zone steps from the colder north to the warmer south and east. The Little Rock dates on this page are a reference point, not a statewide rule.
The zone system is built on one variable, the average annual extreme minimum temperature. It says how cold the worst night of a typical year gets. It does not say when the last spring frost falls. Two places in the same zone can have different frost dates, so use the zone for the question of whether a perennial root like a Jerusalem artichoke survives winter, and use frost dates for the question of when to sow.
A reader in the north of the state or at elevation in the Ozarks should expect colder winters and a tighter frost-free season than Little Rock. The shift runs in a predictable direction, though this page has no figures for it:
- Treat the March 12 to March 28 window as the earliest you would sow, not the middle of it.
- Treat April 3 as an earlier-than-reality date for tender roots, and wait longer.
- Treat October 31 and the November freeze dates as dates that may arrive sooner.
Nobody should read their own zone off this page. Look up your location on the USDA Plant Hardiness Zone Map and read your own half-zone from it. In the southern and eastern parts of the state, the Little Rock dates may run closer to your actual season, but the same rule holds: the reference city is a starting point, and your own frost record outranks it.
Where to check this for your own county
The University of Arkansas Cooperative Extension Service is the place to take this page next. It runs offices at the county level, and those offices know what actually grows in local soil and local weather.
Two things are worth looking for there. The first is the local planting calendar for vegetables, which will show spring and fall sowing windows adjusted for your part of the state. The second is the list of varieties that have been trialled in your county or one close to it. A variety that did well in a trial garden under local conditions is worth more than one that sounds promising on a seed catalog page.
Be plain about the limits of this page. It is the state-level view, built on one reference station at Little Rock plus the National Weather Service light-frost dates. It does not contain a county calendar, a county variety list, or soil-specific advice. A county recommendation beats a state one, because the county office is looking at your actual frost pockets, soil types and rainfall patterns.
When you call or visit, bring the name of the root you want to grow and the planting window you got from this page. Ask whether it has been grown locally, which dates the office would use, and whether the variety needs a different spacing or fertility plan in your soil. The county answer should replace the state one wherever the two differ.
Checking this against your own garden
Your own observations outrank every date above. Three things are worth watching, and none need an instrument.
The first is soil warmth by feel. Push a bare hand into the bed at planting depth. If the soil feels distinctly cold, tender roots will sit and sulk. Compare a sunny raised bed with a shaded corner, and you will learn which spot warms first and which lags. That gap tells you where to put early plantings and where to wait.
The second is the first true leaves on a seedling you sowed early. The first pair to appear are seed leaves, and the true leaves follow. If true leaves show up promptly on a March sowing, the bed is warm enough and drains well. If they stall for weeks, your site is colder or wetter than the reference station suggests, and you should shift later.
The third is the first flush of male flowers on squash or cucumber plants. Male flowers open before female ones, and their arrival means warm-season conditions have settled in. Note the date each year. If it comes late in your garden, your tender-root window starts late too.
Write all three dates down, along with the last frost you actually see. After two or three seasons you will have a calendar that fits your own lot better than any published one.
Common questions
Can I plant unusual roots in fall in Arkansas?
Hardy roots can go in during fall, since the first 32°F freeze falls between November 7 and November 20 and the coldest-month minimum is 30.9°F. Count back from those dates using the days to maturity on the packet. Tender roots cannot, because October 31 is the 36°F light-frost date.
Is March 12 safe for every root?
No. March 12 to March 28 is the 30-70% probability band for the last 32°F freeze, so a freeze after those dates is still possible. Tender roots should wait for April 3.
Does my hardiness zone tell me when to plant?
No. The USDA zone is based on the average annual extreme minimum temperature, which speaks to winter survival, not frost timing. Arkansas spans zones 6b to 8a, so check the USDA map for your own location and use frost dates for timing.
Does this page have a county planting calendar?
It does not. This page uses one reference station at Little Rock and the National Weather Service light-frost dates. For a county calendar and trialled varieties, contact your county office through the University of Arkansas Cooperative Extension Service.