Onion Cultivation, Thrips Control & Scientific Storage (Kanda Chawl) Guide

Onion Cultivation & Scientific Post-Harvest Storage Guide

Onion (Allium cepa) is India's most price-volatile vegetable crop. Over 65% of national production originates during the Rabi season (harvested in April–May). Because fresh Kharif onions do not store well, scientific post-harvest storage of Rabi bulbs in naturally ventilated structures (Kanda Chawl) is essential for stabilizing market prices and avoiding 30–40% storage rotting losses.

1. Seasons & Certified Varieties

• Kharif (June–July Sowing, Nov Harvest): Bhima Super, Bhima Dark Red, Agrifound Dark Red. (Yield: 8–10 tonnes/acre; poor storage life of 1–2 months).
• Late Kharif / Rangda (Aug–Sept Sowing, Jan Harvest): Bhima Red, Phule Samarth.
• Rabi (Oct–Nov Sowing, April Harvest): Bhima Kiran, Bhima Shakti, N-2-4-1, Agrifound Light Red. (Yield: 14–18 tonnes/acre; exceptional storage life of 5–6 months).

2. Nursery Management & Field Transplanting

• Seed Rate: 4 to 5 kg per acre for nursery sowing.
• Nursery Area: 2.5 Gunthas (approx. 250 sq meters) raised beds for 1 acre of transplanting.
• Seed Treatment: Treat seeds with Trichoderma viride @ 5g/kg seed + Thiram 75% WP @ 2g/kg seed to prevent damping-off.
• Transplanting: Transplant 45 to 50 day-old seedlings at 15 cm row-to-row and 10 cm plant-to-plant spacing on raised broad beds (BBF).
• Calculate Population: Use the KhetiSetu Plant Population Calculator.

3. Integrated Weed & Pest Management

1. Pre-Emergence Weed Control: Spray Oxyfluorfen 23.5% EC @ 1ml/liter water or Pendimethalin 38.7% CS @ 2.5ml/liter within 48 hours of transplanting in moist soil.
2. Onion Thrips (Thrips tabaci): Tiny yellowish-brown insects rasping leaves, causing silvery streaks and curling. Spray Fipronil 5% SC @ 1.5ml/liter OR Spinetoram 11.7% SC @ 1ml/liter mixed with a silicone spreader.
3. Purple Blotch (Alternaria porri): Sunken purple-centered oval lesions with yellow halos on leaves. Spray Azoxystrobin 11% + Tebuconazole 18.3% SC @ 1.5ml/liter or Mancozeb 75% WP @ 2.5g/liter.

4. Scientific Post-Harvest Curing & Storage (कांदा चाळ)

Over 80% of storage losses (rotting, sprouting, and desiccation) are caused by poor pre-harvest management:

• Neck Fall & Pre-Harvest Withholding: Stop all irrigation 12–15 days before harvest when 50% of the plants show natural neck fall.
• Field Curing: Harvest carefully without bruising. Field-cure bulbs under their foliage for 3–5 days to shade them from direct sunburn.
• Shade Curing: Remove tops leaving 2.5 cm neck stem attached. Cure under well-ventilated shade for 10–12 days until outer scales turn crisp paper-dry.
• Kanda Chawl Construction Parameters:
  • Structure orientation: North-South to minimize direct heat absorption.
  • Bottom floor elevated 1.5 to 2.0 feet above ground with slatted wooden or bamboo mesh floors.
  • Maximum bulb storage depth: not more than 4 to 5 feet to prevent lower-layer crushing.
  • Naturally ventilated sides (chain-link mesh) with asbestos/tin roofs insulated by thatch.
  • Subsidies available under the MIDH Horticulture Mission and State Agricultural Marketing Boards.