Cultivation

Seeding rate — bulb onion

Allium cepa L. var. cepa

The seeding rate for bulb onions is determined by the target plant density required to obtain marketable bulbs of a specific size, ranging from 600,000 to 800,000 plants per hectare.

In the reference 9 varieties crop Onion, where this is mentioned in the description.

For the production of marketable onions in an annual cropping system, an optimal density is considered to be 650,000–800,000 plants per hectare; the seeding rate is calculated based on the number of viable seeds rather than weight alone. The weight-based rate is typically 3.0–8.0 kg/ha, depending on seed characteristics and the sowing pattern.

Bulb onions are highly sensitive to intraspecific competition and growing space, which requires strict adherence to planting patterns to prevent premature bulb formation. Due to the long germination period and slow initial growth, the seeding rate calculation must include an adjustment for field emergence and potential plant losses during the growing season.

Cultivation technology significantly alters seeding rate parameters: in direct seeding of onion seeds, the rate is higher to ensure the required density, whereas when using sets, calculations are based on the characteristics of the planting material. To obtain larger bulbs, a sparser planting pattern is used, reducing the number of plants to 600,000 per hectare.

General information about the subject — on the page Seeding rate.

Sources8

Varieties of Onion mentioned in the description

Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.