How to Grow Onion
Onion (Allium cepa) is a vegetable crop that yields 15–50 tonnes per hectare and takes 90–140 days from transplanting to harvest. It grows best in well-drained loam, pH 6.0–7.5; friable topsoil for bulb development; no waterlogging, needs 350–550 mm of water, and is widely grown in Armenia, Georgia, Nigeria, Ghana. The current average farm-gate price on GeraFarm is about $0.25 per kg.
Yield / hectare
15–50 tonnes
Time to harvest
90–140 days from transplanting
Avg. price
$0.25/kg
Top regions
Armenia, Georgia
About Onion
Onions are a universal culinary staple with year-round demand. Armenia's Ararat Valley and Uganda's eastern region produce competitive yields; Nigeria and Ghana have large domestic markets absorbing regional production.
Onion growing facts
- Scientific name
- Allium cepa
- Category
- Vegetable
- Yield per hectare
- 15–50 tonnes
- Time to harvest
- 90–140 days from transplanting
- Growing season
- Varies by zone; Armenia: March–April planting, July–August harvest
- Avg. farm-gate price
- $0.25 / kg
- Soil requirements
- Well-drained loam, pH 6.0–7.5; friable topsoil for bulb development; no waterlogging
- Water requirements
- 350–550 mm; critical at bulbing; water withheld 2 weeks before harvest for storage
How to grow onion, step by step
- 1
Prepare soil to the crop’s needs
Test and prepare your soil to match onion's requirement: Well-drained loam, pH 6.0–7.5; friable topsoil for bulb development; no waterlogging. Correct pH and add organic matter before planting.
- 2
Plant in the right window
Plant during the recommended season: Varies by zone; Armenia: March–April planting, July–August harvest. Use certified seed or healthy planting material to avoid carrying over disease.
- 3
Irrigate to target
Supply 350–550 mm; critical at bulbing; water withheld 2 weeks before harvest for storage. Even, well-timed moisture during the critical growth stages drives yield and quality.
- 4
Scout and protect against disease
Watch for Purple blotch (Alternaria) and Downy mildew. Rotate crops, keep good spacing for airflow, and act early — AI disease-scan apps can warn you days before damage is visible.
- 5
Harvest at the right time
Harvest after 90–140 days from transplanting. Handle gently and cool quickly to cut post-harvest losses, which can otherwise reach 20–40%.
- 6
Sell direct for a better price
List your onion free on GeraFarm, set your own price, and sell direct to verified buyers — keeping the margin a broker would otherwise take.
Diseases & pests to watch for
- Purple blotch (Alternaria)
- Downy mildew
- Neck rot (Botrytis)
- Onion fly
- Thrips
Smart-farming tips for onion
- Downy mildew infection period model (leaf wetness + temperature) reduces fungicide applications by 2–3/season
- Bulb size grading AI enables bulk buyers to specify size requirements before delivery
- Post-harvest neck-rot prediction model (field humidity data) guides pre-storage curing decisions
- AI demand forecasting for West African cities (Accra, Lagos) helps export-oriented growers plan volumes
- Onion price crash alerts (from GeraFarm market data) trigger early-harvest vs storage decisions
Get onion price alerts & growing tips
Seasonal onion price updates, planting reminders and disease alerts, plus when to sell for the best price — straight to your inbox. Free.
Growing onion — frequently asked questions
- How much onion can you grow per hectare?
- A well-managed onion crop yields 15–50 tonnes per hectare. Actual yield depends on variety, soil fertility, irrigation, and disease pressure — Armenia, Georgia, Nigeria, Ghana, Kenya are among the leading growing regions. On GeraFarm, growers selling direct typically earn 40–60% more than through traditional middlemen.
- When is the onion growing season and how long until harvest?
- Onion is typically planted in: Varies by zone; Armenia: March–April planting, July–August harvest. It takes 90–140 days from transplanting to reach harvest. Timing your planting to local conditions is the single biggest factor in yield.
- What soil and water does onion need?
- Onion prefers Well-drained loam, pH 6.0–7.5; friable topsoil for bulb development; no waterlogging. Water requirement: 350–550 mm; critical at bulbing; water withheld 2 weeks before harvest for storage. Matching soil and irrigation to these needs is essential for a healthy onion crop.
- What are the main diseases and pests that affect onion?
- The most common threats to onion are Purple blotch (Alternaria), Downy mildew, Neck rot (Botrytis). Crop rotation, certified seed or planting material, good spacing for airflow, and early scouting are the most reliable defences. AI disease-scan tools can flag many of these before they spread visibly.
- Is onion farming profitable?
- Onion sells for around $0.25 per kg at farm gate, and a hectare can yield 15–50 tonnes. Profitability hinges on yield, input costs, post-harvest losses, and the price you can negotiate — selling direct to buyers on GeraFarm removes the broker margin that usually takes 40–60% of the gap between farm-gate and retail price.
- Where can I sell onion after harvest?
- You can list onion free on GeraFarm and reach verified buyers — restaurants, wholesalers, processors and exporters — in 50+ countries. There are no listing fees, only a small commission on completed sales, and you set your own price in your local currency.