Sodate
On this page
Potatoes are grown from certified seed potatoes, planted 10-15cm deep and earthed up as the shoots grow so tubers stay in the dark. First earlies are ready in about 70 days, maincrops in 100-120. Expect 1-2kg per plant, and grow bags work well on a balcony. Critical safety point: green tubers and every green part of the plant contain solanine and are toxic. Never eat a greened potato, store the crop in complete darkness, and keep the foliage away from cats and dogs.
Key facts
- Green patches on a tuber mean solanine has formed. Solanine is toxic and is not destroyed by cooking, so greened potatoes must be discarded rather than peeled and used.
- Grown from certified seed potatoes, not true seed; supermarket potatoes are sprout-inhibited and often carry disease, so they make a poor substitute.
- Earthing up matters because tubers form along the buried stem. Leave them exposed to light and they green and turn toxic.
- The foliage, flowers and green fruits are toxic to cats, dogs and livestock, as with all nightshades.
Growing requirements#
| Plant type | Outdoor cool-season annual grown from seed tubers; frost-tender foliage |
| Growing medium | Loose, free-draining, slightly acidic soil rich in organic matter; avoid fresh lime |
| Light needs | Full sun. 6+ hours daily for the foliage; tubers must stay in complete darkness |
| Water frequency | Even moisture, especially from flowering onward when tubers are bulking; roughly 25mm a week |
| Spacing | 30cm apart for earlies, 38-45cm for maincrops, with 60-75cm between rows |
| Planting season (northern hemisphere) | Plant earlies March, maincrops April to May, after the worst frosts |
| Planting season (southern hemisphere) | Plant August to October in most of Australia and New Zealand; autumn planting suits frost-free subtropics |
| Temperature range | 15-20°C (60-68°F) is ideal; tuber formation slows badly above 27°C |
| Fertilizer | Balanced feed at planting, then higher potassium as tubers bulk; excess nitrogen gives leaf and few potatoes |
| Soil pH | 5.0-6.0: slightly acidic soil suppresses common scab |
| Container suitability | Very good. A 40L grow bag or bin holds 3-4 seed potatoes and yields 2-4kg; add compost as shoots grow |
| Hardiness | Grown as an annual; foliage is killed by frost though tubers survive in the ground briefly |
| Toxicity | Foliage, flowers, green fruits and any green tuber contain solanine and are toxic to people, cats, dogs and livestock |
Harvest, yield & propagation#
| Days to harvest | First earlies 70-90 days, second earlies 90-110, maincrops 100-120 |
| Yield per plant | 1-2kg for a well-grown maincrop; around 1kg for earlies |
| Harvest signal | Earlies once the flowers open; maincrops two to three weeks after the foliage has yellowed and died back |
| Harvest technique | Lift with a fork inserted well outside the plant, on a dry day, and leave tubers on the surface for a few hours to dry |
| Curing & storage | Cure maincrops 10-14 days at 12-15°C, then store in paper or hessian sacks in complete darkness at 4-10°C for 3-6 months. Never store in clear plastic or in light |
| Edible parts | Tubers only, and only while they are free of any green. Leaves, stems, flowers and fruits are never eaten |
| Propagation methods | Certified seed potatoes, chitted for 4-6 weeks in a cool bright spot before planting |
| Companion plants | Beans, marigold and horseradish; keep well away from tomatoes, which share blight |
Common problems & troubleshooting#
| Symptom | Likely cause | Fix |
|---|---|---|
| Green patches on harvested tubers | Light exposure in the ground or in storage, producing solanine | Discard affected tubers; do not peel and eat them. Prevent it by earthing up thoroughly and storing in complete darkness |
| Brown-black blotches on leaves spreading fast in warm damp weather | Late blight (Phytophthora infestans) | Cut off and remove all foliage immediately, then wait 2-3 weeks before lifting so spores on the soil surface die off |
| Rough, corky scabs on the tuber skin | Common scab, worst in dry alkaline soil | Cosmetic only and still edible after peeling. Keep soil evenly moist during tuber formation and avoid liming the bed |
| Tunnels bored through the tubers | Wireworm or slugs, common on newly broken grassland | Lift maincrops earlier, avoid leaving them in the ground into late autumn, and rotate off recently turfed ground |
| Leaves stripped by striped beetles and fat larvae | Colorado potato beetle (in the Americas and parts of Europe) | Hand-pick adults and crush the orange egg clusters on leaf undersides; use Bt or spinosad for heavy infestations |
| Tall leafy plants but tiny tubers | Too much nitrogen, or insufficient earthing up | Feed high potassium rather than high nitrogen, and earth up whenever 15-20cm of shoot appears |
Get a blight warning before the crop is lost
Sodate watches your local humidity and temperature for the exact two-day window that triggers potato blight, so you can cut the haulm in time to save the tubers.
Seasonal care#
Varieties & cultivars#
| Variety | Distinguishing trait | Note |
|---|---|---|
| 'Charlotte' | Second early, waxy salad potato | Excellent boiled, holds shape |
| 'Maris Piper' | Maincrop, floury texture | The UK standard for chips and roasting |
| 'Yukon Gold' | Early maincrop, yellow flesh, all-purpose | North American favourite |
| 'Sarpo Mira' | Maincrop with strong blight resistance | Best pick for wet summers |
| 'Dutch Cream' | Large creamy-fleshed maincrop | Popular in Australia |
Buying checklist#
- Buy certified seed potatoes, not supermarket potatoes, which are sprout-inhibited and can carry disease
- Choose first early, second early or maincrop deliberately, based on how long you can leave the ground occupied
- Look for firm tubers with small strong sprouts, not long white weak ones
- Pick a blight-resistant variety if your summers are warm and wet
- Reject any seed potato with soft rot, mould or green patches
Pricing by region#
| Region | Price range | Typical unit | Basis |
|---|---|---|---|
| US | $8 – $18 | 1-2kg bag of certified seed potatoes | Nursery + mail-order retail |
| UK | $5 – $13 | 1-2kg net of seed potatoes | Garden centre retail |
| India | $0.6 – $1.8 | 1kg seed tubers | Agri supply + local market |
| Australia | $8 – $17 | 1kg certified seed potatoes | Nursery + garden centre |
| Canada | $7 – $16 | 1-2kg certified seed potatoes | Garden centre retail |
USD figures are approximate conversions for comparison; switch the dropdown to see each region's actual local-currency listing price.
Often confused with#
Name confusion warning#
Do not confuse potato with sweet potato. They are in different plant families and grow in completely different ways. In India "aloo" always means potato and sweet potato is "shakarkandi"; in parts of the US southern states sweet potatoes are confusingly labelled "yams", which is a third, different plant again. Also note that "seed potato" means a tuber for planting, not actual seed.
Where it's actually grown#
Seed potatoes for gardeners come from certified schemes in cool, aphid-free regions, notably Scotland, the Netherlands, Canada's Maritime provinces, Idaho and Tasmania, where virus pressure is low enough to keep stock clean over successive multiplications. This is the whole reason certified seed exists: potatoes accumulate viruses through their tubers, so the industry constantly refreshes stock from high-latitude nurseries rather than letting growers save their own indefinitely.
Import & biosecurity restrictions#
| Region | Note |
|---|---|
| Australia | Seed potato imports are effectively prohibited and even interstate movement is restricted; buy certified stock domestically. |
| US | State-level quarantines apply to seed potato movement; buy certified seed within your state where possible. |
| UK | Certified seed potatoes are widely sold; post-Brexit imports from the EU require phytosanitary certification. |
| India | Domestic certified seed is supplied through state agriculture departments; imports need quarantine clearance. |
| Canada | CFIA regulates seed potato certification and interprovincial movement; use certified domestic stock. |
Similar plants
Did you know?
Frequently asked questions
Are green potatoes poisonous?
Yes. Green colouring indicates solanine, a toxic glycoalkaloid that forms when tubers are exposed to light. Cooking does not destroy it, so green potatoes should be thrown away rather than peeled and eaten. Store your crop in complete darkness to prevent it.
Why do I need to earth up potatoes?
New tubers form along the buried section of stem. Earthing up gives them more dark soil to develop in, increases the yield, and stops tubers near the surface from being exposed to light and turning green and toxic.
Can I plant potatoes from the supermarket?
It is a poor idea. Supermarket potatoes are usually treated with sprout inhibitors and are not screened for the viruses and diseases that certified seed potatoes are. Certified seed costs little and avoids importing blight and virus into your soil.
Are potato plants toxic to cats and dogs?
Yes. The leaves, stems, flowers and green fruits contain solanine and are toxic to cats, dogs and livestock. Cooked, non-green tubers are safe, but keep pets away from the foliage and from any greened potatoes.
How many potatoes does one plant produce?
Typically one to two kilograms for a healthy maincrop plant, and around one kilogram for an early variety. A 40 litre grow bag with three or four seed potatoes will usually give two to four kilograms.
