Potatoes require a cool but frost-free growing season. Grow potatoes through the summer in cool northern regions. Grow potatoes in fall, winter, and spring in hot summer southern regions.
- Plant potatoes as early as 4 to 6 weeks before the average last frost in spring or any time after the soil temperature warms to 40°F (4.4°C).
- Potatoes need 75 to 135 or more cool, frost-free days to reach harvest depending on the variety.
- Harvest late winter or spring-planted potatoes before daily temperatures average 80°F (27°C)
- Potatoes do not grow well in extreme heat or dry soil. High temperatures can cause mature potatoes to discolor inside.
Which potato to plant: Potato Types and Varieties.
Planting Potatoes
Where to Plant Potatoes
- Grow potatoes in full sun.
- Plant potatoes in fertile, well-drained soil rich in organic matter. Add several inches of aged-compost or commercial organic planting mix to planting beds before planting.
- Loosen the soil to 18 inches (45cm) deep or grow potatoes in raised or mounded beds.
- Do not grow potatoes where the soil is compacted, heavy with clay, or constantly wet.
- A soil pH of 5.0 to 5.5 is best for potatoes. Alkaline soil increases the size of the crop but also increases the incidence of scab–a condition that affects the skin of the potato.
Planting Time for Early, Midseason, and Late Season Potatoes
Potato varieties are classified according to the number of days they require to come to harvest. The ideal temperature for growing potatoes is 60° to 70°F (16-21°C); temperatures greater than 80°F (26°C) are usually too warm for potatoes. Grow a variety that can come to harvest in cool to mild, not hot, weather.
- “Early” season (early maturing) varieties require 75 to 90 cool days to reach harvest. Early potatoes are the best choice for southern regions where summers become very warm or hot.
- “Midseason” varieties require 90 to 135 cool days to reach harvest.
- “Late-season” (also called long season) varieties require 135 to 160 cool days to reach harvest. Late-season potatoes are a good choice for northern regions where the weather stays mild all summer.
Spring Planting Potatoes. Plant potatoes 3 to 4 weeks before the last spring frost; in Zone 7 and warmer, plant a second crop in late summer or fall. Time the planting in spring so that new foliage is not killed by the last frost.
In mild summer regions, you can plant early, mid-season, and late-maturing cultivars in spring for an extended harvest season.
Summer Planting Potatoes for Autumn Harvest. Plant potatoes no later than 12 weeks before the first expected autumn frost.
Winter Growing in Mild-Winter Regions. If you live where winters are mild and summers are hot, plant late-season potatoes in winter for harvest in mid to late spring before the weather turns hot or plant early-season potatoes in late summer for a fall crop.
Growing Potatoes in Sub-Tropical and Tropical Regions. In tropical and subtropical regions potatoes can be grown all year round, although they are best planted in summer and autumn for harvest before the rainy season.
Yield. Potatoes are highly productive and can yield 6 to 8 pounds (3-4kg) of tubers per square yard (meter).
Preparing Seed Potatoes for Planting
- Grow potatoes from “seed potatoes.” Seed potatoes can be whole potatoes or pieces of whole potatoes.
- Potatoes are swollen stems, not roots.
- A seed potato must have at least one “eye” to sprout. An “eye” is a bud, a puckered spot where sprouts develop; sprouts develop stems and leaves.
- Plant certified disease-free seed potatoes. Supermarket potatoes have been chemically treated to inhibit sprouting. Seed potatoes can be purchased at a garden center or from mail-order suppliers.
- Store seed potatoes in the refrigerator for up to one month before planting.
- You can plant seed potatoes whole, or cut them to about the size of a medium egg, with two or three buds apiece.
- Two or three weeks before planting, set seed potatoes in a bright, 65° to 70°F (18-21°C) place to encourage sprouting.
- Cut whole seed potatoes into pieces with a sharp knife two days before planting; each piece should have at least two eyes After cutting, you should let the pieces cure for one to two days at 75°F (24°C).
- Even if you are planting whole seed potatoes, it’s best to cure them in a warm place for two days before planting; this will encourage the best growth.
- Plant seed potatoes in a hole or trench 3 to 4 inches (7.5-10cm) deep and cover with 2 inches (5cm) of soil.
- Plant cut pieces with the cut side down.
- If you prefer not to dig, or if the soil is heavy clay or wet, you can lay the tubers on the soil surface and cover them with 4 to 6 inches (10-15cm) of straw or composted leaves.
Planting and Spacing Potatoes
- Early Varieties Spacing: Sow early variety seed potatoes 8 to 14 inches (20-35cm) apart; space rows 12 to 18 inches (30-45cm) apart.
- Late Varieties Spacing: Sow late variety seed potatoes 12 to 14 inches (30-35cm) apart; space rows 30 to 36 inches (75-90cm) apart.
- When seedlings (developing sprouts) emerge, add the remaining 2 inches (5cm) of soil to the hole or trench.
- Keep adding light soil as plants grow tall. Leave the top two sets of leaves exposed.
- Potatoes also can be planted on top of the ground if they are covered with a 12-inch (30cm) thick mulch of straw or hay.
- Each plant will produce about 5 to 10 potatoes or 3 to 4 pounds (1.3-1.8 kilo).
Crop Rotation. Potatoes are related to bell peppers, chili peppers, and eggplants; all are prone to the same diseases. Don’t grow potatoes where any of these vegetables have grown in the past four years.
Container Growing Potatoes
- Potatoes can be grown in containers. Use a shallow wooden box or a half barrel with the bottom removed; use stacked old tires or use special potato-growing bags or barrels.
- Plant seed potatoes at the bottom of the container.
- When plants grow from 8 to 10 inches (20-5cm)all, add enough soil to cover all but the top 2 or 3 sets of leaves. Continue this process until the maturity date for the variety you are growing then harvest.
Growing Potatoes in Trenches, Mulch or Containers.
Companion Plants for Potatoes
- Grow potatoes with beans, cabbage, corn, eggplant.
- Avoid planting potatoes near cucumbers, pumpkins, squash, sunflowers, tomatoes, or raspberries. These plants are attacked by the same pests and diseases as potatoes.
Caring for Potatoes
Watering Potatoes:
- Keep potatoes evenly moist but not wet; water before the soil dries out.
- Potato tubers will rot if the soil is too wet.
- Even soil moisture is important; fluctuations in soil moisture—wet, dry, wet—can lead to cracked or knobby tubers.
- Mulch to protect tubers from the sun, conserve soil moisture, prevent the soil from becoming too warm, keep weeds down, and discourage pest insects.
Feeding Potatoes:
- Feed potatoes by sprinkling 5-10-10 fertilizer across the planting bed before planting; add this again as a side dressing at midseason. Choose a fertilizer that includes calcium and magnesium.
- Avoid giving potatoes too much nitrogen; too much nitrogen will encourage foliage growth over tuber growth.
- Where the soil is poor, drench the soil with a cup or more of compost tea shortly after planting. Spray-mist foliage with compost tea every two weeks through the season.
Maintaining Potatoes:
- Be careful not to compact the soil around potatoes. Use boards between rows to avoid walking on the soil.
- Protect maturing tubers from sunlight by hilling up soil over plants or applying additional mulch to all but cover the plants. Exposed tubers will sunburn or their shoulders will become green (called greening). Green potatoes produce a chemical called solanine. Solanine is both bitter-tasting and toxic.
- Carefully cultivate around plants or mulch to keep weeds down.
Hilling Potatoes:
- Exposure to light can cause potato tubers to turn green; the green skin is slightly toxic.
- Protect the tubers from light by “hilling up” soil when the green shoots or stems are about 4 to 5 inches (10.12.5cm) tall. Use a hoe to mound up soil leaving just a few leaves exposed to sunlight. Hilling will also keep the tubers cool and moist. Hill the plants again two or three weeks later.
- Surface-planted potatoes can be filled by piling mulch deeply around the plant; you can use straw or composted leaves rather than soil.
Potato Pests and Diseases
Potato Pests:
- Potatoes can be attacked by Colorado potato beetles, leafhoppers, flea beetles, and aphids. Potato beetles and flea beetles chew holes in leaves. Cover plants with floating row covers until midseason to exclude these pests.
- Handpick both adults and larvae Colorado potato beetles and destroy them.
- Use Bacillus thuringiensis to control potato beetles, leafhoppers, and flea beetles.
- Knock aphids off plants with a strong blast of water.
- Stunted plants with puckered or yellow leaves, small bumps on the tubers, or hard galls on the roots have been attacked by root-knot nematodes; destroy infected plants. To prevent nematode problems, plant a cover crop of marigolds,and apply beneficial nematodes to the soil.
Potato Diseases:
- Potatoes are susceptible to blight and scab.
- Spray plants with compost tea every two weeks to control blights.
- Scab can cause potatoes to have rough skin but does not affect the eating quality of the potato. Cut away the corky areas
- If scab is a problem, adjust the soil pH to 5.5.
- Plant disease-resistant varieties and practice crop rotation.
More on potato problems: Potato Growing Problems: Troubleshooting.
Harvesting and Storing Potatoes
Harvesting Potatoes:
- Potato stems and leaves turn brown and flowers fade as tubers below ground mature.
- Potato tubers can be harvested at any size. Potatoes harvested before they mature are called new potatoes.
- New potatoes can be harvested when plants are in full bloom.
- As potatoes mature their skins harden. The skin of a new potato will easily peel off when rubbed. New potatoes cannot be stored but must be used right away.
- A potato plant will produce 3 to 6 regular-size potatoes and a number of small ones.
- Use a spading fork to dig up potatoes. Lift potatoes gently to avoid bruising or damaging the skins. Use your fingers to harvest potatoes if need be.
- You can harvest the whole plant or gently break off tubers, removing a maximum of two tuber per plant if you intend to let the plant grow on and harvest again.
- To harvest mature tubers, wait until the tops of the plants die back. Leave the tubers in the ground for a few weeks after the tops die back; this will allow the skins to toughen and the potatoes will store better.
- Test one or two potatoes before lifting the entire crop. Use damaged potatoes immediately and store the rest in a dark, dry place, with good air circulation.
- Potatoes can be left in the ground past maturity until the first frost, but they are most nutritious if harvested when they mature.
- If first is not imminent and vines are not dying back, knock the vines flat or cut them with a knife to kill them. You can then proceed to harvest.
- Early potatoes take about 60 days to reach maturity; mid-season potatoes take about 80 days; late-season potatoes need 90 days or longer to mature.
- Protect harvested potatoes from sunlight; potatoes exposed to light will green and produce a bitter chemical compound called solanine.
- Allow potatoes to cure before storing them. Curing will harden the skins for storage. Set tubers in a single layer in a dark place at 50° to 60°F (10-15°C) for two weeks to cure.
- Brush excess dirt off the tubers, but don’t wash them; they are best stores with dirt on, as this helps exclude light and stop them from turning green.
- Store potatoes at about 40° (4.4°C).
- Potatoes will also store well in the ground as long as the weather is not too wet or warm.
- Save the best tubers for planting next season. Don’t save potatoes that are soft or discolored. Don’t save potatoes if any of the plants have been hit by a disease.
When to harvest: Potato Harvest Calendar.
Storing and Preserving Potatoes:
- Store potatoes in a dark, well-ventilated place at about 40°F (4.4°C). Do not wash them before storing; allow them to air dry at 50-65°F (10-18°C) for five days before storing.
- Potatoes will keep for about 6 months.
- Do not refrigerate potatoes.
- Prepared or new potatoes freeze well. Potatoes also can be dried.
Potato Varieties to Grow
- There are more than 100 varieties of potatoes.
- There are four basic potato categories: long whites, round whites, russets, and round reds. You can also grow potatoes with yellow or bluish-purple skins.
- Potato flesh may be white or match the skin color: red, yellow, or blue.
- Potatoes can be round, cylindrical, or finger-like, called fingerlings
- Potatoes can be categorized as moist or dry. Dry potatoes are good for baking and mashing (varieties include ‘Russet Burbank’ and ‘Butte’). Moist potatoes fall apart when cooked; they are a good choice for soups.
- Check your cooperative extension service for specific recommendations for your area.
Recommended Varieties: Here are potato varieties to grow in a home garden:
- ‘All Blue’: midseason medium-sized potato with blue skin and blue-purple flesh; use mashed, steamed, baked, roasted, and in salads.
- ‘Butte’: early season; baking.
- ‘Caribe’: early season; drought tolerant; all-purpose use.
- ‘Carola’: late-season; yellow flesh; all-purpose use.
- ‘Cranberry Red’: early- to midseason; red skin and pink, smooth flesh; use mashed, steamed, roasted, and in salads.
- ‘French Fingerling’: late-season; use roasted, baked, and in salads.
- ‘Katahdin’: midseason; use French-fried, baked, mashed, or roasted.
- ‘Purple Peruvian’: late-season; use roasted, baked, and in salads.
- ‘Red Gold’: midseason: all-purpose use.
- ‘Red Norland’: early season; use boiled, steamed, mashed, or in salads.
- ‘Red Thumb’: early season fingerling; roasting.
- ‘Rose Finn Apple’: late-season; all-purpose use.
- ‘Russian Banana’: late-season; use roasted, baked, or in salads.
- ‘Yellow Finn’: midseason yellow-fleshed variety; all-purpose use; good for mashing and baking.
- ‘Yukon Gold’: early season; use boiled, mashed, or in a salad.
Related articles: Potatoes for Cooking; also Potatoes: Kitchen Basics
About Potatoes
- The potato is a perennial vegetable grown as an annual.
- Botanical name: Solanum tuberosum
- Origin: Chile, Peru, Mexico
Grow 80 vegetables: THE KITCHEN GARDEN GROWERS’ GUIDE
