When to Plant Potatoes

Updated August 2026 · Garden Advice Guide

Plant potatoes 2 to 4 weeks before your last spring frost, once the soil at 4 inches deep has warmed to about 45 to 50°F. Potatoes tolerate a light frost on their foliage and the seed pieces sit safely underground, so you can start earlier than you would with tomatoes or beans. In warm zones 8 through 10 the whole schedule flips: potatoes are a fall and winter crop there, planted from September through February, because summer soil is far too hot for tubers to form.

Everything hangs on your last frost date, so get yours first with our free frost date lookup, then count back two to four weeks and check the soil with a thermometer before you dig.

Soil temperature is the real trigger, not the calendar

The frost date gives you a window. Soil temperature tells you which day inside that window to actually plant.

Potato seed pieces need soil at 45°F minimum to start rooting, and they're much happier at 50 to 55°F. Below 45°F they just sit there, wet and dormant, while soil fungi go to work on the cut surfaces. That's how you lose a bed before anything comes up.

Measuring it takes ten seconds. Push a soil thermometer 4 inches deep, first thing in the morning before the sun has warmed the surface, and read it. Do that three mornings running. If all three read 45°F or higher and the trend is upward, plant.

A few things move that reading faster than the calendar does:

• Raised beds warm 5 to 10°F ahead of flat ground, sometimes by two full weeks.
• Sandy soil warms faster than clay. Heavy clay in a cold spring can lag three weeks behind a sandy bed a hundred feet away.
• A sheet of black plastic laid down for 7 to 10 days will pull a cold bed up into range early.
• South-facing slopes and beds against a wall run warmer than open ground.

That's why two gardeners in the same zip code can plant two weeks apart and both be right.

When to plant potatoes by zone

Here's the practical version of the window, zone by zone. Treat the month as your alert and the soil temperature as your go signal.

If you don't know your zone, the USDA Plant Hardiness Zone Map gives it to you by zip code.

Two patterns are worth pulling out of that table. In the North, the constraint is spring cold at one end and first frost at the other, so variety choice matters. In the South, the constraint is summer heat in the middle, so you plant around it rather than through it.

Zones 8 to 10: right now is your planting window

If you're in zone 8, 9, or 10, late August through fall is the most important paragraph on this page.

Potatoes set tubers best when soil sits between 60 and 70°F. Tuber formation slows sharply above 75°F and essentially stops above 80°F, which is why a southern potato patch planted in April makes lush green vines all summer and almost nothing underground. The plant isn't failing. It's just too warm to do the one job you wanted it to do.

So the southern schedule looks like this:

• Zone 8: plant September through mid-October. Vines grow through the mild fall, tubers set as soil cools into the 60s, and you harvest December into January. A second crop goes in late February.
• Zone 9: plant October through November for a January to March harvest, or January to February for a late spring crop before the heat arrives.
• Zone 10: plant anytime from September through February. December and January plantings do well because the soil never gets cold enough to rot seed pieces.

A hard freeze will knock the tops back in zones 8 and 9. That's survivable. Hill soil over the plants before a cold night, or throw a frost blanket on, and the plant regrows from the crown. The ranking of what actually works on a freeze night puts those two near the top. Tubers under 6 inches of hilled soil come through fine.

Fall potato planting pairs well with the rest of the cool-season southern garden. Our roundup of what to plant in September covers what else goes in alongside them.

Seed potatoes vs grocery store potatoes

Buy certified seed potatoes. This is the one place in the vegetable garden where the cheap substitute genuinely doesn't work, for two separate reasons.

Sprout inhibitors. Most potatoes sold for eating are treated after harvest with a sprout suppressant so they stay firm on the shelf for months. That treatment does exactly what it says. Plant a treated potato and you get slow, patchy, or nonexistent emergence. Some sprout eventually and some never do, and you won't know which until three weeks of your season are gone.

Disease certification. Certified seed is grown in inspected fields and tested for the diseases that live inside a tuber and can't be washed off: late blight, ring rot, blackleg, potato virus Y, and common scab among them. Those pathogens go into your soil with the seed piece and some of them stay there for years, which turns one bad bag into a bed you can't plant potatoes in again.

University of Maine Cooperative Extension, in a state that grows a serious share of the country's seed potatoes, makes the same point in its home garden guidance: certified seed is the foundation of a healthy crop, and saved or grocery tubers are a common route for disease into a garden.

Certified seed is inexpensive by the pound. A pound plants roughly 6 to 8 feet of row and returns 8 to 10 pounds of potatoes, so the math is not close.

What about saving your own seed from last year's crop? You can, and gardeners do it successfully for a few seasons. Just know that viruses accumulate invisibly year over year, yields drift downward, and the fix is buying fresh certified stock every third or fourth year.

Chitting: is pre-sprouting worth it?

Chitting means setting your seed potatoes out to sprout before they go in the ground. Put them in a single layer in an egg carton or shallow tray, eyes facing up, somewhere bright but cool, around 50 to 60°F, for 2 to 4 weeks before planting.

You want short, stubby, green-purple sprouts about half an inch to an inch long. Those are strong. The long white bean-sprout shoots that form in a dark closet are weak and snap off during planting, so light matters more than warmth here.

Is it worth doing? Honest answer: sometimes.

• Worth it for first earlies, where chitting can pull the harvest forward by a week or two. In a short season that's real.
• Worth it in cold, slow springs, because a pre-sprouted piece emerges faster and spends less time vulnerable in cold soil.
• Not worth much for main crop varieties. They have plenty of season either way, and the yield difference is small.
• Skip it if your seed already has sprouts. It's already done the job for you. Just handle the tubers gently.

Cutting and curing seed potatoes

Small seed potatoes, roughly egg-sized or smaller, go in whole. Larger ones get cut.

Aim for pieces of about 1.5 to 2 ounces with at least two eyes each. That's roughly the size of a large ice cube or half a small potato. Smaller pieces run out of stored energy before the roots take over, and pieces much larger than 2 ounces are just wasted seed.

Cut with a clean knife, and wipe the blade with rubbing alcohol between tubers if you're working through mixed stock, since a knife will happily carry ring rot from one potato to the next.

Then cure the cut surfaces for 2 to 3 days. Spread the pieces in a single layer somewhere around 60 to 70°F with decent humidity and air movement, out of direct sun. The cut face dries and forms a corky skin, which is the whole point: a healed cut resists rot in cold soil, a fresh wet cut invites it.

If you're planting into warm, well-drained soil you can get away with planting the same day. Into cool spring soil, curing is close to essential.

Planting depth, spacing, and layout

The standard layout, and it works nearly everywhere:

1. Dig a trench 4 inches deep. Some gardeners go 6 inches in sandy soil, 3 inches in heavy clay.
2. Set pieces 12 inches apart, cut side down, sprouts pointing up.
3. Space rows 30 to 36 inches apart. That gap isn't for the plants. It's the soil you'll pull up over them when you hill.
4. Cover with 3 to 4 inches of soil. Don't fill the trench completely yet if you're using the trench-and-fill method.
5. Water once, well, then leave the bed alone until sprouts appear in 2 to 3 weeks.

Tighten the in-row spacing to 10 inches if you want more, smaller potatoes for boiling. Widen it to 15 inches for fewer, larger bakers.

Skip fresh manure and go easy on high-nitrogen fertilizer. Too much nitrogen gives you a beautiful leafy plant and a disappointing dig, and fresh manure is associated with worse scab.

Hilling, and why it decides your yield

Here's the thing that surprises first-time potato growers: tubers form on stems above the seed piece, not below it. The seed potato makes roots downward and stolons upward, and the stolons are where potatoes come from.

That means the amount of loose soil above your seed piece more or less sets your yield ceiling.

Hilling is how you add it. When the plants are 6 to 8 inches tall, pull soil from between the rows up around the stems, burying the lower half of each plant and leaving the top few inches of leaves showing. Repeat 2 to 3 weeks later when they've grown another 6 to 8 inches. Two hillings is standard, three is better.

Hilling does three jobs at once:

• More tuber-bearing stem means more potatoes per plant.
• Buried tubers stay dark. Any potato that pokes into daylight turns green and produces solanine, which is bitter and shouldn't be eaten.
• Weed control and moisture retention come free with the soil you move.

Straw, shredded leaves, or compost work as hilling material if your soil is heavy. The tubers form clean and lift out easily.

Get the hilling right and the harvest end takes care of itself; our guide on when to harvest potatoes picks up from there.

Containers and grow bags

Potatoes do genuinely well in containers, and the timing rules don't change: same soil temperature target, same window relative to your last frost. The one advantage is that container mix warms faster than ground soil, so you can often plant a week or two ahead of the bed.

What works:

• Minimum 10 gallons per plant, 15 gallons if you can. A 15-gallon fabric grow bag holds 2 to 3 seed pieces comfortably.
• Start with 4 to 6 inches of mix in the bottom, set the seed pieces on it, cover with another 3 to 4 inches.
• Add mix as the plant grows, burying the lower stems each time until the bag is full. That's hilling, just vertical.
• Water more than feels necessary. Containers dry out fast, and uneven watering is what causes hollow heart and knobbly tubers.
• Fabric bags beat plastic pots because they drain better and don't cook the roots in afternoon sun.

Expect 2 to 4 pounds per 15-gallon bag from an early variety. It's not a season's supply, but it's the easiest way to grow potatoes on a patio.

The one real risk: planting into cold, wet soil

Potatoes are tough, but the seed piece is vulnerable for the two or three weeks between planting and emergence. During that window it's a chunk of starch sitting in the ground with a cut surface on it.

In cold soil, growth is slow and the piece stays exposed for longer. In wet soil, fungi and bacteria are active and oxygen is scarce. Cold and wet together is the combination that produces seed piece rot: you dig up a soft, foul-smelling lump three weeks later and nothing ever came up.

How to avoid it:

• Wait for 45°F soil at 4 inches, measured, not guessed.
• Never plant into ground that's still saturated from rain. Squeeze a handful of soil, and if it stays in a tight ball and glistens, wait.
• Cure your cut surfaces properly.
• Plant shallower, 3 inches instead of 5, in a cold spring, then hill more aggressively later.
• Use a raised bed if your soil is heavy and your springs are wet.

Planting two weeks late into good conditions beats planting on time into a mud bath every year.

Worked example: zone 5 with a May 15 last frost

Take a zone 5 garden with an average last frost of May 15. Here's the whole plan on a calendar.

Around March 28: buy certified seed and start chitting. Set the tubers eyes-up in trays by a cool bright window at about 55°F.

April 17 to May 1: this is the planting window, 2 to 4 weeks before May 15. Start checking soil temperature at 4 inches each morning around April 15.

April 22: three consecutive mornings read 47, 48, and 50°F. Green light.

April 22: cut seed into 2-ounce pieces with two eyes each, spread them out to cure.

April 25: plant. Trench 4 inches deep, pieces 12 inches apart, rows 32 inches apart, covered with 3 to 4 inches of soil.

May 10 to May 15: sprouts break the surface, right around the last frost date. If a frost is forecast, pull soil over the shoots or cover the row overnight. Frosted tops regrow, they just cost you a week.

May 25 and June 12: first and second hilling.

Mid July (day 80): first earlies are ready to dig.

Early September (day 130): main crop vines yellow and die back. Wait two weeks for the skins to set, then dig around September 20. Zone 5's first fall frost is typically around October 1, so there's a comfortable margin.

Notice the total: from planting to a stored main crop is about five months, and the whole schedule was set by one measurement in late April.

If you're mapping a full season rather than one crop, our planting calendar by zone lays out the same kind of math for everything else in the bed. And if you're planting potatoes this fall in the South, garlic goes in around the same time and wants a similar soil temperature.

FAQ

When can I plant potatoes, exactly?

Plant 2 to 4 weeks before your average last spring frost, as soon as soil at 4 inches deep reads 45°F or higher on three consecutive mornings. In zones 8 to 10 the answer is different: plant in fall and winter, from September through February, and skip the summer entirely.

What is the best time to plant potatoes in a cold northern zone?

In zones 3 and 4, wait for late May when the soil finally reaches 45°F, and choose first or second early varieties that finish in 70 to 100 days. Raised beds and black plastic can pull that date forward by a week or two, which matters a lot when the season is short.

Can potatoes handle a frost after planting?

The seed pieces underground are safe from any spring frost. Emerged foliage gets damaged around 30°F and killed near 28°F, but the plant regrows from the crown and just loses about a week. Hilling soil over young shoots or covering the row overnight avoids the setback.

Can I plant potatoes from the grocery store?

You can try, but expect disappointment. Most eating potatoes are treated with a sprout inhibitor, so emergence is slow or fails outright, and untested tubers can introduce soil-borne diseases that persist for years. Certified seed potatoes are inexpensive by the pound and remove both problems.

Do I have to chit potatoes before planting?

No, chitting is optional. It gains you a week or two on early varieties and helps in cold, late springs, but main crop potatoes do fine planted straight from the bag. If your seed potatoes have already sprouted in storage, that's chitting done for you.

How deep should potatoes be planted?

Four inches deep is the standard, with pieces 12 inches apart in rows 30 to 36 inches apart. Go shallower, around 3 inches, in heavy or cold soil and hill more aggressively later. Depth at planting matters less than the total soil you pile on during the season, since tubers form above the seed piece.

When do you plant potatoes for a fall harvest?

In zones 7 and warmer, plant a fall crop roughly 110 to 120 days before your first expected frost, which usually means late July through September depending on how far south you are. In zones 8 to 10 that fall planting is the main crop, not a bonus, and it typically outyields anything planted in spring.

How long from planting to harvest?

First earlies take 70 to 90 days, second earlies about 95 to 110, and main crop varieties 120 to 135 days. New potatoes can be dug earlier, around 60 to 70 days, once the plants have been flowering for 2 to 3 weeks. Add two weeks after die-back before lifting anything you plan to store.

Updated August 2026