Onion Seed

For onion sets please click here.

Sow in open ground 1cm (^1/2") deep in rows 23-30cm (9 to 12") apart as thinly as possible. Thin seedlings to final spacing required in two stages. For show onions sow in greenhouse at the turn of the year hardening off in March for planting out in April. Sow outdoors as soon as ground conditions permit, late February to end of March. The Japanese variety - Senshyu should be sown at the end of August to the first week of September, 2.5cm (1") apart and thinned to 10cm (4") in the spring.

Sow salad onions successionally from March to August.

For general garden crops the site should be moved each year to prevent the build up of diseases like White Rot. A well prepared bed should be provided with a fine tilth and good drainage. Good weed control is essential (as it is with sets) especially early on. Most commonly noted problems are onion fly, white rot and bolting. The effect of onion fly can be reduced by careful thinning and destroying all thinnings immediately, as will using sets or pot grown plants thereby avoiding any thinnings. An eight year break from onions and their relatives is the only long term cure for white rot.  Bolting can be almost eliminated if care is taken, avoid planting in cold wet soil.