How to grow onions at home in India — from sets, seed, and scraps

Onions are one of the most-used vegetables in every Indian kitchen, and there are three very different ways to grow them at home: from sets (small pre-grown baby bulbs), from seed, and by regrowing spring onions from scraps. Each gives a different result, and it helps to be honest up front — growing full-size storage bulbs on a terrace is genuinely hard, while growing spring onions (green onions) is easy and quick.

This guide walks through all three methods, the kharif and rabi planting windows across India, which varieties to look for, how deep a pot you actually need, and how to feed and water so you get bulbs instead of just leaves. It also explains the single most common home-grower complaint — "all leaf, no bulb" — and how to avoid it. Read the honest expectations section before you commit a whole terrace to onions.

Bulb onions vs spring onions — decide first

These are the same plant grown two ways, and mixing them up causes most disappointment.

Spring onion (green onion / hara pyaz): you eat the whole young plant — green tops and a small white base — before it forms a bulb. Fast, forgiving, thrives in a shallow pot, and you can start any time of year. This is the reliable terrace crop.
Bulb onion (the storage onion you chop for sabzi): the plant must grow leaves for months, then swell a bulb in response to day length and cool weather. It needs the right season, deeper soil, and patience — and terrace results are often modest.

If you want a steady kitchen supply with little fuss, grow spring onions. If you want the challenge of real bulbs, read on and plant in the correct season.

When to plant onions in India

Onion bulbing is triggered partly by day length and temperature, so season is everything for bulb onions.

Kharif (monsoon crop): sow seed in nursery around June–July, transplant in August, harvest November–December. Good for early bulbs but rain and humidity bring disease.
Late kharif: nursery August–September, transplant October, harvest January–February.
Rabi (main crop): nursery around October–November, transplant December–January, harvest April–May. This is the biggest and best-storing crop across most of India, and the easiest window for a home grower to get real bulbs.

Spring onions ignore all of this — sow any time, though the cool rabi months (October–March) give the lushest growth in the north.

Choosing sets, seed, or scraps

Sets are small immature bulbs (about 1–2cm) that you replant; they're the fastest, most reliable route to a bulb because the plant has a head start. Sets are less common in Indian nurseries than in the West, but you can sometimes buy small "chhoti gaanth" onions or grow your own from a thick seed sowing. Push a set into soil and it grows straight to a bulb.

Seed is the standard commercial route and the cheapest. A packet costs roughly ₹40–₹90. Seed is slow — you raise a nursery for 6–8 weeks, then transplant pencil-thick seedlings. Onion seed loses viability fast, so buy fresh each season.

Scraps — the root end of a shop onion or a spring onion — will regrow green shoots in water or soil. This gives you usable green leaves quickly, but a scrap rarely makes a good new bulb. Treat it as free spring onion, not a bulb crop.

Varieties to ask for:

Pusa Red, Pusa Ratnar — popular red bulb onions for the north.
N-53 (Nasik Red) — a well-known kharif red for western India.
Agrifound Dark Red — widely grown kharif red.
Agrifound Light Red, Bhima Shakti, Bhima Super — rabi and multi-season types from ICAR's onion research work.
Arka Niketan, Arka Kalyan — from IIHR Bengaluru, good for the south.

Container size and soil

Onions are shallow-rooted, but a bulb needs room to swell.

Spring onions: a shallow trough 15cm deep is enough. Any wide grow bag or even a repurposed paint bucket works.
Bulb onions: at least 20–25cm of soil depth and, more importantly, width, because bulbs need horizontal space. Space seedlings/sets 10cm apart in every direction.
Volume: a 10–15 litre grow bag holds 5–6 bulb onions or a thick clump of spring onions. Wide and shallow beats tall and narrow for onions.

Soil mix: loose, rich, free-draining. Roughly 40% loam, 30% compost or vermicompost, 30% cocopeat or sand. Onions like fertile soil but hate waterlogging — see our potting mix recipe for Indian terraces and the best grow bag size guide.

Step-by-step planting

From seed:

Sprinkle seed thinly in a nursery tray or corner pot; cover lightly with fine soil.
Keep moist and shaded until germination (7–12 days).
When seedlings are pencil-thick and about 15cm tall (6–8 weeks), lift gently.
Trim the very tips of the leaves and roots, then transplant into the final container 10cm apart, roots just covered — don't bury the growing point deep.

From sets: push each small bulb into the soil so the tip just shows, 10cm apart. Done.

For spring onions: sow seed thickly and don't thin much, or plant sets/scraps close together. Harvest young.

Give onions full sun, 6+ hours. Less sun means weak plants and poor bulbs.

Watering and feeding

Watering: keep soil consistently moist during leaf growth — uneven watering stresses the plant. Once bulbs start swelling, keep it steady, then stop watering 1–2 weeks before harvest so the bulbs cure and skins firm up. Never let onions sit in water; rot spreads fast in humid weather.

Feeding: onions need nitrogen early to build the leaf frame (more leaves early means a bigger bulb later), then more phosphorus and potassium as bulbs form.

Mix compost or vermicompost into the soil at planting.
3 and 6 weeks after transplant, feed a nitrogen source — diluted cow-dung slurry, vermicompost tea, or mustard-cake water.
As bulbing begins, switch to a potassium-leaning feed (wood ash worked lightly into the top, or a low dose of an NPK like 13:00:45 / 00:52:34).
Stop nitrogen once bulbing starts — late nitrogen is the number one cause of "all leaf, no bulb."

For the organic slurry and cake recipes, see organic feeding for leafy greens.

Pests and problems

Thrips: the main onion pest in India — silvery streaks and curled leaf tips, worst in warm dry weather. Spray neem oil (5ml/litre + a drop of soap) in the evening, repeat weekly.
Purple blotch / leaf blight: purple-brown patches on leaves in humid kharif weather. Improve airflow, avoid wetting the foliage, remove affected leaves.
All leaf and no bulb: wrong season (day length not triggering bulbing), too much nitrogen, too little sun, or crowding. Grow in the rabi window, feed nitrogen early only, and give full sun.
Bolting (flower stalk): cold snaps or stress make the plant flower; snap the stalk off, but that bulb won't store well — eat it soon.
Small bulbs: usually crowding, poor sun, or short season. Space wider and start on time.

Photograph anything odd and check it with /diagnose.

Harvest, cure and store

Spring onions: harvest any time from about 4–6 weeks — either pull the whole plant or snip the green tops and let them regrow a couple of times.

Bulb onions: the sign is the tops falling over and the necks going soft, with lower leaves yellowing — around 4–5 months from transplant depending on season. When about half the tops have flopped:

Stop watering and let them sit a few more days.
Lift on a dry day and leave the bulbs on the surface or a shaded rack to cure for 1–2 weeks until the skins are papery and necks fully dry.
Trim roots, cut or plait tops, and store in a cool, airy, dry place. Well-cured rabi onions store for a couple of months at home.

Yield expectations — the honest version

Growing full-size storage onions on a terrace is one of the harder home projects in India. Limited soil volume, city day-length and heat, and disease pressure mean home bulbs are often small — think 3–5cm, not the fist-sized ones from the mandi. A 15 litre bag of 5 plants might give five smallish onions after four months, which is not a great return on space or time.

Spring onions are the opposite: a single wide trough gives you cut-and-come-again green onions for weeks, and they regrow from scraps for free. Our honest advice — grow spring onions for the kitchen, and try a bag or two of rabi bulb onions as an experiment rather than your main supply.

FAQ

Q: Why are my onions all leaf and no bulb?

A: Usually the wrong season (day length isn't triggering bulbing), too much nitrogen fertiliser late in growth, too little sun, or overcrowding. Grow in the rabi window, feed nitrogen only in the early weeks, give full sun, and space plants 10cm apart.

Q: Can I grow onions from kitchen scraps?

A: You can regrow green shoots from the root end of a shop onion or spring onion — great for green tops. But a scrap rarely forms a good new bulb, so treat it as free spring onion, not a bulb crop.

Q: How deep should the pot be for onions?

A: Spring onions need only about 15cm depth. Bulb onions need 20–25cm and, more importantly, width — bulbs swell sideways, so wide, shallow containers beat tall narrow ones.

Q: Sets or seed — which is better for home growing?

A: Sets are faster and more reliable because the plant already has a head start toward a bulb. Seed is cheaper and more available in India but slow (6–8 weeks of nursery first). For a quick result, use sets; for volume on a budget, use fresh seed.

Q: When should I plant onions in India?

A: The rabi crop is best for home bulbs — nursery in October–November, transplant December–January, harvest April–May. Kharif sowing is June–July. Spring onions can be sown any time of year.

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