Vegetable · Solanaceae
Potato
Solanum tuberosum
Tuck a few cut tubers into the soil, keep them hilled and watered, and you will dig up a generous crop by fall.
Full sun
Every 3–7 days
50–77°F · 10–25°C
70–120 days
Overview
The potato belongs to the nightshade family, a relative of the tomato and pepper, and it grows as a cool-season crop. Its story begins high in the Andes, where people bred it for food thousands of years before it traveled to the rest of the world. The part you dig up and eat is the tuber, a swollen underground stem packed with starch, so even though it lives in the ground it is not truly a root.
Most of the wonder with potatoes happens out of sight, under the soil. You set cut pieces of seed potato in the ground, each one carrying an eye, and before long leafy stems rise while small underground shoots quietly fatten into tubers. The one job that matters most is hilling, drawing soil up around the stems so the young tubers stay buried in the dark. Leave one in the light and it turns green and bitter, but a little mounding keeps that from happening.
Give potatoes loose, fertile ground on the acidic side and steady water once the tubers set, and even a small bed can keep your kitchen supplied for months. They also store beautifully, so a single fall harvest can carry you comfortably into winter. There is a lot of forgiveness built into this crop, which makes it a reassuring one to learn on.
Care
The short version: give potatoes full sun, loose slightly acidic soil rich in organic matter, and even moisture once the tubers start forming. Feed them at planting, keep the nitrogen light, and mound soil up the stems as they grow, and they will reward the effort.
Light
Potatoes are happiest in full sun, ideally 6 or more hours of direct light each day. They will manage in partial sun, but the tops grow weaker and the tubers stay smaller, so give them the brightest, most open spot you have. Do not worry if your garden is not perfect; they are patient about most things but genuinely love the light.
Water
Keep the soil evenly moist, which comes out to about 1 to 2 inches of water a week, and be especially steady once the tubers start to swell. Try not to let the ground stay soggy, since waterlogged soil invites rot and disease. A consistent, gentle rhythm is easier on the plants than long dry spells broken by a flood.
Soil
Plant in loose, well-drained sandy loam with plenty of organic matter mixed in. Potatoes prefer things on the acidic side, a pH of 5.0 to 6.0, which happens to keep scab in check as a bonus. That loose, open texture also lets the tubers swell freely, so the crumblier you can make the bed, the better.
Temperature
Potatoes do their best growing in cool weather, somewhere between 50°F and 77°F (10°C to 25°C). When the heat climbs, tuber growth slows down, which is exactly why an early start pays off and lets the plants get going before summer arrives. If a warm spell passes through, do not panic; the plants simply pause and pick back up.
Humidity
Ordinary outdoor humidity suits potatoes just fine, so there is no target number to chase here. What matters far more is good airflow, because damp, crowded foliage is the kind of setting late blight loves. A little breathing room between plants goes a long way toward keeping them healthy.
Feeding
Work a balanced fertilizer into the bed at planting time, then give a small side-dressing of nitrogen as the plants come up and you hill them. Go gently with it, though, since too much nitrogen grows lush green tops at the expense of the tubers you are actually after. A light touch here really does serve the crop better.
Pruning
There is no real pruning to fuss over, which is one more reason potatoes are easy on a beginner. Just pull off any diseased leaves as soon as you notice them, and keep hilling soil up the stems to bury the growing tubers and stop them from greening in the light. That gentle mounding is the main bit of hands-on care they need.
Size & spacing
Plants grow 1 to 3 feet (30 to 100 cm) tall and spread about 12 to 24 inches (30 to 60 cm) across. Give each one a little elbow room and mound the soil generously around it, because that buried space is exactly where your crop takes shape. There is no need to be precise; a comfortable, roomy bed is all they ask.
When to plant
Potatoes like to go in early, while the ground is still cool, so there is no need to wait for warm weather. Set the seed pieces out 2 to 4 weeks before your last frost, once the soil has warmed to around 45°F to 50°F (7°C to 10°C). From there you can slip a few new potatoes from the soil in midsummer and lift the main storage crop in fall, after the tops have died back on their own.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Early spring, about 2-4 weeks before the last expected frost once soil reaches roughly 45-50°F
- Harvest: Harvest new potatoes about 60-70 days after planting; harvest mature storage potatoes about 90-120 days after planting once tops die back
Hardiness
USDA hardiness zones: 3–9
Temperature: down to -40°C
Troubleshooting
Nearly every potato trouble turns up in one of two places: on the leaves while the plants are growing, or on the tubers once you dig them. The good news is that only a handful really matter, and catching them early keeps them small. Look through the ones below, find the one that matches, and deal with it gently while it is still easy to handle.
Dark, greasy patches and foliage that suddenly wilts in damp weather
Those spreading dark blotches are late blight, caused by the same Phytophthora that troubles tomatoes, and it can move fast through a bed after a cool, wet stretch. On humid mornings you may spot brown-black lesions rimmed with pale edges and a soft white fuzz on the leaf undersides. Do not lose heart: pull and destroy the affected plants right away instead of composting them, and sort out any rotted tubers before they ever reach storage.
Fix:
- Remove and destroy infected plants immediately
- Do not compost infected material
- Apply an approved fungicide preventively where blight is present
- Harvest carefully and cull infected tubers before storage
Striped beetles and plump red grubs eating the leaves
The Colorado potato beetle is the crop's most serious pest, and a big group can chew a plant down to bare stems in short order. Turn the leaves over and look for orange egg clusters, soft red larvae, and the adults marked with ten black stripes. It is very manageable, though: handpick them into soapy water, tuck row cover over young plants, and shift the planting to fresh ground each year.
Fix:
- Handpick adults, larvae, and egg masses into soapy water
- Use row covers early in the season
- Apply an approved insecticide if infestation is heavy
- Rotate planting location yearly
Green skin on the tubers, sometimes with a bitter taste
A tuber turns green wherever light reaches it near the surface, and that green tissue carries solanine, the toxin that leaves a potato bitter and unsafe. More often than not it comes down to thin hilling that left the tubers exposed. The fix is gentle and simple: mound soil over them as the plants grow, discard any heavily greened potatoes, and store your harvest somewhere cool and dark.
Fix:
- Hill soil up over exposed tubers as plants grow
- Discard heavily greened tubers
- Store harvested potatoes in cool, dark conditions
- Cut away minor green areas before cooking
Rough, corky, scabbed patches on the tuber skins
Those corky patches are common scab, a soil bacterium that tends to flare when the ground dries out during tuber set or the pH drifts too high. Peel one tuber and you will likely find the lesions are only skin deep, with sound flesh underneath, so the harvest is still good to eat. Keep the soil evenly moist while the tubers form, hold the pH down around 5.0 to 5.5, and skip fresh manure, and it usually fades away.
Fix:
- Maintain even soil moisture during tuber formation
- Keep soil pH slightly acidic (around 5.0-5.5)
- Plant scab-resistant cultivars
- Avoid fresh manure and alkaline amendments
Toxicity
The cooked tuber on your plate is a safe, everyday food, and that part you never have to worry about. The rest of the plant is a different story: the leaves, stems, sprouts, and any green or raw potato hold a natural toxin called solanine that can make both people and animals ill. Trim off any green spots, throw away badly greened tubers, and keep the vines and sprouts out of reach of pets, livestock, and children.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds
Safe for
People
Cats Caution
A cat that chews the leaves, stems, or a green sprouted tuber takes in solanine, and drooling and vomiting usually follow, with diarrhea and low energy close behind. A large dose can reach the heart and nervous system, so if more than a nibble went down, it is worth calling your vet to be safe.
Dogs Caution
Dogs that dig up and gnaw raw or green tubers, or browse on the foliage, tend to get an upset stomach, loose stools, and a sluggish mood. Keep a close eye on them, since larger amounts of glycoalkaloid can affect the heart rhythm and are worth a vet's attention.
Horses Caution
The vines and any green or sprouted potatoes are best kept away from horses entirely. Solanine can bring on colic, drooling, and a dull, unsteady stance, and a horse grazing fallen foliage may take in enough to need a vet's help.
Rabbits Caution
Keep rabbits away from the leaves, stems, and green tubers, because their small size means even a little solanine can cause real trouble. A poor appetite, a bloated belly, and weakness are the signs to watch for if any is eaten.
Livestock Caution
Cattle, sheep, pigs, and goats can make themselves ill on discarded vines or piles of green and cull potatoes left in a field. The solanine sets off digestive upset, and once enough builds up it can add staggering and trembling, so it is safest to clear those scraps away.
Birds Caution
Keep chickens and other birds away from the foliage, sprouts, and any greened scraps, since all of them hold solanine. A little cooked plain potato is perfectly fine for them, but the green, raw parts are the ones to avoid.
People Cooked tuber safe
A cooked, properly stored potato is a safe everyday staple you can enjoy without concern. The trouble sits only in the green skin, the sprouts and eyes, and all the foliage and stems, which carry solanine that turns a potato bitter and can make you ill, so cut away green spots, toss any badly greened tuber, and keep the vines off the plate.
Cooked, properly stored potato tubers are a safe food. The hazard is the foliage and any green, raw, or sprouted tubers, which contain solanine.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
There are hundreds of potato varieties out there, grouped mostly by skin color, flesh texture, and what they cook up best for. The four below are friendly, dependable choices you will find in most gardens and grocery bins.
Yukon Gold
Yukon Gold is a thin-skinned yellow potato with buttery, all-purpose flesh, and it has become the reliable standard many kitchens reach for first.
Russet Burbank
Russet Burbank is a large, oblong potato with brown skin and flesh so starchy that it is the classic pick for baking and frying.
Red Pontiac
Red Pontiac is a red-skinned, white-fleshed variety loved for its steady yields and how gracefully it keeps in storage.
Kennebec
Kennebec is a vigorous white potato that crops heavily and shrugs off more disease than most, which makes it a comforting choice for a first garden.
Companions
Potatoes do well beside nitrogen-fixing beans and a few traditional partners, and badly beside their nightshade relatives and sprawling vines that crowd them and trade diseases.
Plant near
Bush beans: Legumes fix nitrogen and are reported to help repel some potato pests.
Corn: Traditional companion that does not compete heavily and shares no major potato diseases.
Cabbage-family crops: Generally compatible bed companions that do not share potato's key diseases.
Horseradish: Often planted near potatoes and is said to improve overall plant vigor and pest resistance.
Keep apart
Tomato: Another solanaceous crop that shares late blight and other diseases, increasing risk to both.
Cucumbers and squash: Sprawling cucurbits crowd potatoes and can increase disease pressure.
How to propagate
There are two ways to start potatoes, but for almost every home gardener one of them is the clear and comfortable choice.
Bulbs & cormsEasy
Early spring, 2-4 weeks before the last frost · Sprouts emerge in about 2-4 weeks after planting
Nearly everyone grows potatoes from certified seed-potato pieces, each cut so it carries one or two eyes and left to cure for a day or two before planting. Set them out in early spring, 2 to 4 weeks before the last frost, about 4 inches deep, and the sprouts will push through in roughly 2 to 4 weeks. From there, just keep mounding soil up the stems as the plants climb, and they take it from there.
SeedDemanding
Indoors in late winter · Several weeks to germinate and grow on before transplanting
Starting from true botanical seed is a much bigger undertaking, sown indoors in late winter and grown on for several weeks before it can be transplanted. Because the offspring come out so variable, home gardeners rarely take it on, and the method stays mostly with breeders. For a first crop, the seed-potato route is by far the kinder path.
Myths
Because the tubers are a familiar food, every part of the potato plant must be safe to eat.
Only cooked tubers that have been stored well and never turned green are safe to eat. The leaves, stems, sprouts, and any green or raw tuber all carry solanine, which really is toxic, so the plant as a whole is not something to nibble freely. Enjoy the tubers with confidence, and simply leave the rest of the plant alone.
Potatoes must be grown from true seed, the way other vegetables are.
Almost every home gardener plants certified seed-potato pieces instead, each cut to include one or more eyes. True botanical seed is rarely used outside plant breeding, since it gives a mixed, unpredictable set of offspring. So there is no need to hunt for potato seeds; a few good seed potatoes are all you need to begin.