Onions can be grown from seed or plugs. To start from seed prepare a small area for the seedbed. It can be either raised (if water is no problem) or sunk, to capture more water. It should be 1,2m (4ft) wide, with 8 rows 10-15cm apart. Make 1 cm deep furrows along the rows. Mix the seeds with the same amount of sand and fill the furrows evenly with the sand-seed mix. Cover thinly with high quality fine compost and water thoroughly. Water several times per day for the first 14 days until all seedlings have emerged. Even afterwards daily watering is important. After emergence apply mulch between the rows to suppress weeds and pull out any emerging weeds carefully by hand as onions do not compete well with weeds. After 4 weeks apply a liquid fertilizer made from stinging nettle.
Transplant when the seedlings are the size of a pencil and have 4-5 leaves. Prior to transplanting water the seedbed heavily to ease the uprooting and also irrigate the field into which the onions will be transplanted. To help seedlings recover quickly after transplanting prepare a liquid fertilizer from comfrey and mix it with some soil and fresh cow manure until it forms a thick sludge. Pull up the seedlings from the seedbed carefully and dip their roots in the manure-comfrey mix. Bunch about 50 seedlings together and cut off 50% of the green tops. Transport to the field and transplant immediately.
Drip irrigation with 4cm emitter spacing between the rows is advisable as irrigation of 3-5mm per day is necessary, but overhead irrigation and water logging must be avoided as onions are prone to fungal diseases and rot. Mulching between the rows is important. Irrigation should completely stop for the last three weeks before harvest. Lift up the whole plant and bunch onions together at their leaves. Hang them up in an airy space for about a week until the outer parts are completely dry and the leaves can be pulled off easily. Cutting off green leaves will reduce storage life and promote rot.
Time of Sowing/Transplanting
9 plants / sqft
Pests and Diseases