Potato

Mid-October to end of November across most of northern India, timed so tuber bulking lands in the coolest weeks of winter. Planting outside this window measurably caps final tuber size, whatever else is done right. Hill states such as Himachal Pradesh grow a separate spring/summer crop instead, since elevation keeps temperatures in potato’s preferred range even in those months.

Roughly 10–12 quintals per acre (25–30 q/ha) of whole or cut seed tubers — about 20–24 bags of 50 kg each. Seed alone is 40–50% of the total cost of growing potato, far higher than for a cereal crop, because certified, disease-free tubers cost several times what grain seed does per kilogram.

Farm-saved or uncertified seed is the single most common way a viral or bacterial disease — including potato leaf roll virus and black scurf — carries over from one season to the next. A field grown from certified, disease-free tubers starts every season with a clean slate.

A common recommendation is 180:80:100 kg/ha of N:P:K, with full phosphorus and potash plus half the nitrogen at planting, and the rest of the nitrogen top-dressed at earthing-up. Potato removes more potassium per tonne of produce than almost any other crop grown in India, so the potash dose matters more here than for a cereal.

Roughly 6–8 light irrigations, since potato is grown almost entirely under irrigation rather than on rainfall. The two irrigations to never skip are at tuber initiation (30–40 days), which sets how many tubers the plant carries, and through tuber bulking (50–80 days), which sets their final size.

250–350 quintals per hectare under normal irrigated management; over 350 q/ha is achievable with certified seed, timely planting and no major late blight outbreak.

When the haulm (foliage) yellows and dries naturally, or is deliberately cut 7–10 days before lifting to toughen the skin — usually 90–120 days after planting depending on variety. Tuber skin that no longer rubs off easily when pressed with a thumb is a reliable sign the crop is ready.

Cure freshly lifted tubers in a shaded, ventilated spot for 10–15 days to heal minor cuts, then hold them in a cold store at 2–4°C and 90–95% relative humidity — good for 4–6 months, against just 4–6 weeks in ambient storage during warm weather. Cold storage access, more than field yield, decides how much of a bumper crop reaches a good price.

No — potato has no central Minimum Support Price. Several states run a Market Intervention Scheme (MIS) to support prices in a glut year, and the live mandi price on this page is the most useful real-time signal for when to sell from storage.

Yes, under PMFBY (Pradhan Mantri Fasal Bima Yojana). Potato is classified as an annual commercial/horticultural crop, so the farmer’s premium is capped at 5% of the sum insured — higher than the 1.5–2% cap for food-grain crops. Enrolment is seasonal, so check your state’s cut-off date before planting is complete.

Sunlight reaching the tuber through thin or rain-washed ridges triggers chlorophyll and solanine formation together — the green tinge and the bitterness/mild toxicity go hand in hand. Earthing-up at 25–30 days, and again if rain washes the ridges down, is the only real prevention; a green potato should not be eaten.

Uniform yellowing that starts on older, lower leaves usually points to nitrogen deficiency — check whether the second (top-dress) dose of nitrogen at earthing-up was applied on schedule. Yellowing with browning leaf margins instead suggests potassium deficiency, which shows up more in potato than in cereals since the crop removes exceptionally high potash per tonne. If it appears late in the season alongside natural drying of the haulm, that is simply the crop maturing, not a problem. Persistent yellowing with wilting despite normal watering can also mean waterlogged roots or early bacterial wilt — check drainage first.

Upward, leathery rolling that starts on the lower leaves and spreads up the plant is the classic sign of potato leaf roll virus (PLRV), spread by aphids — infected seed tubers are the most common source, which is exactly why certified seed matters so much. If curling instead shows up on a hot, dry afternoon and the leaves flatten out again by evening or after the next irrigation, it is ordinary moisture-stress curling, not disease, and irrigation on schedule fixes it. Uproot and destroy any plant confirmed with virus-pattern curling so aphids don’t spread it further in the field.

Fertilizer alone doesn’t set tuber size — irrigation and timing usually matter more. The two biggest causes are irregular watering during the 50–80 day tuber-bulking window, since potato needs even, undisrupted moisture through this stage rather than just total water, and planting too late, which cuts the bulking period short before summer heat arrives. Overdoing nitrogen without matching potash can also push the plant into leafy growth at the tuber’s expense — check the potash dose specifically, not just total NPK. Small or poor-quality seed tubers, or planting too densely, are the other common causes.

Growth cracks usually come from a sudden flush of water after a dry spell during tuber bulking — the outer tissue cannot stretch fast enough for the sudden growth. Even, light irrigation every 7–10 days through bulking, rather than one heavy watering after a gap, prevents it.

This is “hollow heart”, a physiological disorder rather than a disease — it happens when a tuber grows unusually fast and large, most often in oversized tubers after a sudden flush of water following a dry spell, similar to what causes external cracking. Wide plant spacing, low plant population, or excess nitrogen that pushes tubers to grow oversized also raise the risk. Even, scheduled irrigation through the bulking stage and standard plant spacing (20 cm within rows, 60 cm between ridges) keep tuber size — and hollow heart risk — in check.

Sudden wilting in patches, especially in warm, waterlogged soil, is the classic sign of bacterial wilt (Ralstonia solanacearum) — cut a wilted stem near the base and look for a milky ooze; there is no chemical cure once it has set in, so remove and destroy affected plants and avoid replanting potato in that patch for 2–3 years. Wilting that comes with blackened, water-soaked stems during a foggy spell instead points to late blight moving from leaves into the stem, which needs an immediate fungicide spray. Waterlogged or poorly drained soil after heavy rain or over-irrigation can also cause root rot and wilting even without disease — check drainage first before assuming infection.

Late blight (Phytophthora infestans) starts as small, dark, water-soaked patches on leaf tips and margins, with white fungal growth visible on the underside of leaves in humid mornings — it spreads through a field within days once cool, foggy, humid weather sets in and can destroy an entire crop within ten days if an infected week goes untreated. Spray a preventive fungicide such as mancozeb as soon as a foggy spell begins, before any lesions appear; once lesions are visible, switch to a curative fungicide like cymoxanil + mancozeb or a metalaxyl-based product, since a plain protectant no longer stops an infection that has already established.

Waterlogged, poorly drained soil is the most common cause — standing water after heavy rain or over-irrigation starves tubers of oxygen and lets bacterial soft rot (Pectobacterium/Erwinia) set in, usually entering through wounds from insects, poor earthing-up, or careless intercultural operations. Tubers can also rot from late blight itself: spores washed off infected foliage during rain move down into the soil and infect tubers directly, which is why continuing to spray for foliar blight matters even close to harvest. Good ridge drainage, avoiding irrigation right before a heavy rain spell, and lifting tubers promptly once mature all reduce the risk.

The largest, lowest-cost yield gains come from getting the basics right rather than adding more inputs: certified, disease-free seed tubers planted in the first half of the recommended window, standard spacing (20 cm between plants, 60 cm between ridges), and irrigation that stays even and uninterrupted through the 50–80 day tuber-bulking stage. Working 15–20 tonnes/ha of well-rotted farmyard manure into the soil before planting improves both yield and tuber quality without raising the chemical fertilizer bill, and treating seed tubers with a biofertilizer/fungicide dip before planting cuts the early disease loss that otherwise eats into the final harvest. Timely earthing-up at 25–30 days protects tuber number and size just as much as any nutrient input does.