Potential of Adelaide, Cradock and Middelburg, South Africa, for out-of-season onion production using different planting materials and planting dates

Abstract

Out-of-season onion production is used to produce onions for the early market (April to September) when onion prices peak. No information with regard to this production method is available for the Eastern Cape. Field experiments were therefore conducted in Adelaide, Cradock and Middelburg (situated in the Fish River catchment, Eastern Cape, South Africa) to determine its viability in this area. The short-day onion cultivar ‘Z516’ was established with sets (bulbs 10–12 mm diameter) and seed on five planting dates (late January, mid February, late February, mid March and late March) in a randomised block with four replications. Marketable and unmarketable yields were recorded and percentage marketable yield of total yield calculated. Results indicated that seed is not suitable for out-of-season onion production. Sets produced the highest marketable yields and marketable yield percentage when planted in Adelaide in late February (39.68 t ha⁻¹ [93%]), mid-March (62.60 t ha−1 [92%]) and late March (50.40 t ha−1 [89%]) and matured from April to September when onion prices peak. Cradock is marginal and Middelburg is unsuitable for out-of-season onion production because of low winter temperatures, especially from May to September.

Keywords:

• bolting
• marketable and unmarketable onion yield
• planting date
• seed
• sets