Planting Potatoes in August

Yes, an August potato crop needs 90 to 120 days of suitable growing weather before damaging cold, and the soil must cool enough for tubers to form. University of Maryland Extension gives that maturity range for home-grown potatoes, but the exact timing depends on your variety, soil temperature, and local fall weather.

An August planting can work in warm regions with a long fall, or in protected containers and greenhouses. It is usually a poor bet where hard freezes arrive early or where the soil stays hot well into fall.

Use this quick check before buying seed potatoes.

Decision	August Planting Works When	What to Check
Time remaining	Your variety has 90 to 120 days before damaging cold	Check the maturity date on the seed-potato variety information and compare it with your local frost outlook
Soil temperature	Soil is 60°F to 70°F, where tuber formation is strongest	Do not expect tubers to form if soil reaches 80°F
Local planting calendar	Your county still lists a fall-potato window	Maryland guidance extends early varieties only through June 1; Arkansas lists July 15 to August 1 for fall production. Confirm your own state or county Extension calendar.

When August Potato Planting Works

An August crop makes sense only when soil is cooling and fall offers enough uninterrupted growing weather for your variety.

Potatoes can grow leafy vines in warm weather without making many usable potatoes. The underground tubers form best in soil between 60°F and 70°F. At 80°F, tubers fail to form, according to Illinois Extension. That is why an August planting is not simply a matter of being in a warm zone.

Check the soil in the actual bed or container you plan to use. Raised beds, black containers, and dry bare soil can stay warmer than nearby ground. A bed that feels comfortable in the morning may still become too hot during the afternoon.

An August crop is most realistic when:

You can use certified seed potatoes rather than grocery-store potatoes.
You have a sunny bed with loose, well-drained soil.
You are willing to harvest smaller “new” potatoes if the full storage crop does not have time to mature.

Sustained warm autumn weather can let late potatoes continue growing toward a late-fall or winter harvest.

How to Plant Potatoes in August

Step 1: Start With Certified Seed Potatoes

Buy certified disease-free seed potatoes from a reputable supplier. Grocery-store potatoes and potatoes saved from last year’s garden may carry viruses or other diseases without obvious symptoms.
Use small seed potatoes whole when possible. Cut larger tubers into seed pieces that weigh 1½ to 2 ounces, roughly 1½-inch cubes, with 1 to 3 buds, or “eyes,” on each piece.
Discard seed potatoes that are soft, badly shriveled, moldy, or visibly diseased.

For a late planting, use an early-maturing variety if one is available. A variety that needs a long season may produce foliage but not enough mature potatoes before cold weather slows it down.

Step 2: Prepare the Bed and Set the Spacing

Choose a spot with direct sun for at least 6 hours daily; potatoes perform best with 8 to 10 hours of sun.
Loosen the soil and mix in finished compost if the bed is low in organic matter. Remove rocks, clods, and old roots that could distort developing potatoes.
Lay out rows 24 to 36 inches apart.
Place seed potatoes 8 to 12 inches apart within each row. Use the closer spacing if you want smaller new potatoes; use wider spacing if you want larger potatoes for storage.

Avoid a low spot that stays wet after rain. Potatoes need moisture, but seed pieces and young tubers can rot in saturated soil.

Step 3: Plant the Seed Pieces Deeply

Dig furrows or individual holes 5 to 6 inches deep for an August crop.
Set each seed piece cut-side down, with the eyes facing upward or to the side.
Cover with loose soil and water enough to settle the soil around the pieces.

The deeper planting depth helps protect late-season tubers from heat as the soil shifts during fall rains.

Step 4: Water and Feed the Growing Plants

Keep the root zone evenly moist as plants emerge and begin to form tubers. Do not let the bed repeatedly dry out and then become flooded; uneven moisture can lead to misshapen or cracked potatoes.

Side-dress the plants with fertilizer 6 weeks after planting, when tubers begin to form. Use the amount recommended by a soil test or the fertilizer product directions for vegetable beds, and keep fertilizer off the stems and leaves.

Step 5: Hill Soil Around the Stems

As plants grow, pull loose soil around the lower stems to keep developing potatoes covered. Exposed potatoes turn green in sunlight and should not be eaten.

Keep the final hills no more than 6 inches above the original soil grade. A modest hill is enough to cover tubers without burying the plants under a large mound of heavy soil.

Managing Late-Season Heat, Rain, and Cold

Late-season potatoes need management for hot soil, heavy rain, and early frost to support tuber growth and harvest.

Hot Soil in Late Summer

The foliage may look healthy while tuber production remains poor.

Mulch can help moderate soil temperature and conserve moisture, especially in raised beds. Keep mulch loose around the stems rather than packed tightly against them. Closely spaced rows also shade the soil once plants fill in.

In persistently hot conditions, use the space for a crop better suited to late-summer heat.

Heavy Rain and Humidity

Late summer can bring wet weather, especially in humid areas. Avoid walking on the soil around plants, which compacts the root zone.

Check the plants regularly for declining vines, damaged stems, or potatoes pushing through the soil.

Early Frost Risk

A light frost may slow the vines, but a hard frost can stop late growth before the crop reaches full size. If cold weather is approaching and the tubers are usable, harvest rather than waiting for a perfect storage crop.

Containers offer an advantage here: you can move them to a bright, frost-free location for a short extension of the season. Ground-grown potatoes are harder to protect once repeated freezes begin.

Harvesting and Storing an August Potato Crop

Harvest new potatoes 6 to 8 weeks after planting, while mature potatoes need curing before dark, humid winter storage.

Harvesting New Potatoes

Harvest small, tender new potatoes 6 to 8 weeks after planting, usually once the plants have flowered.

Loosen the soil at the side of a plant instead of pulling the whole plant immediately.
Feel for a few potatoes and remove only what you need.
Replace the soil around the remaining roots so the plant can keep growing.

I use a hand trowel for this because it lets me uncover a few potatoes without spearing the rest of the developing crop.

Use new potatoes soon after harvest. Their skins are thin and they do not keep as long as mature storage potatoes.

Harvesting Potatoes for Storage

For potatoes you want to store:

Wait until the vines die back naturally.
Leave the tubers in the ground for 2 weeks after the plants die back so their skins can thicken.
Dig only when the soil is reasonably dry. Lift gently with a shovel or garden fork placed well outside the plant’s center.
Brush off loose soil, but do not wash the potatoes before storage.
Cure the potatoes for 10 to 14 days at 50°F to 60°F with high humidity so small cuts and wounds can heal.
Move cured potatoes to a dark, humid place at 38°F to 40°F for winter storage. Temperatures below 38°F can cause internal damage.

Discard green potatoes rather than trying to store them. Green skin is associated with solanine, a bitter toxic compound.

August Potatoes in Containers and Greenhouses

Containers are useful when your garden soil is too warm, too wet, or unavailable. Use a large container with drainage holes, loose potting mix, and enough room to add soil around the stems as they grow.

A black pot sitting on hot concrete can become warmer than an in-ground bed, so place it where the root zone is protected from intense reflected heat.

For a winter crop in a greenhouse, use cold-stored seed potatoes. That approach can also work in parts of the U.S. where a small greenhouse stays bright without becoming excessively hot.

Do not use an ordinary unheated greenhouse as a solution to hot August weather. It may raise soil and air temperatures instead. The greenhouse approach is most useful later in the season, when frost protection, not summer cooling, is the problem.

How to Tell Whether the Crop Is Progressing

Healthy foliage alone does not prove that potatoes are forming. When plants are established, carefully check beside one plant for developing tubers without disturbing the entire root system.

A crop is progressing well when:

The plants stay green and upright through the cool part of the season.
Soil remains covered by foliage, mulch, or modest hills.
Small tubers are present when you gently inspect beside a plant.
The bed drains after rain instead of holding water.

If the vines are vigorous but there are few or no potatoes, the soil may have remained too warm during tuber formation. In that case, harvest any usable small potatoes, clear the bed after the crop finishes, and plan the next potato planting for a cooler part of the year.

Frequently Asked Questions

Can Yukon Gold potatoes grow if planted in August?

Yes, Yukon Gold can grow from an August planting if the soil cools enough for tubers to form and your local fall season is long enough for the variety to mature. Yukon Gold is not a special exception to late-season timing; check the maturity information from the seed-potato supplier before planting. If cold arrives early, you may still harvest small new potatoes rather than a full storage crop.

Can I plant potatoes in August in Zone 8b?

Sometimes, but Zone 8b alone is not enough information to decide. Check your county Extension planting calendar, soil temperature, and the maturity time listed for your seed potatoes. In Arkansas, midseason and late varieties may be planted as late as July 15 to August 1 for fall production.

When Should I Plant Potatoes in Zone 7a?

For a regular main-season crop, plant in spring when the soil is workable and the weather is cool. Maryland’s planting period is March 15 to May 1, depending on location. An August planting may be grown as a fall crop.

Can I Plant Potatoes in August in Zone 5?

Usually not for a full in-ground storage crop. Check your local frost dates before planting. A protected container, greenhouse, or a plan to harvest small new potatoes gives you a better chance of getting something useful from the crop.

What Potatoes Can I Plant in August in the UK?

Use prepared cold-stored seed potatoes intended for a late greenhouse crop. Plant them in July or early August in a large container inside a greenhouse or another bright frost-free location. The goal is a protected autumn or winter harvest rather than a normal outdoor main crop.

Will potatoes planted in August have time to develop?

Potatoes planted in August may develop, but a full crop needs 90 to 120 days to mature under suitable conditions. If the season is shorter, you may still be able to dig small new potatoes about 6 to 8 weeks after planting. Tuber production is strongest when the soil is 60°F to 70°F and stops at 80°F.