Growing Onions in Hydroponics

Onion
(Allium cepa)
Planting Info:
Grown from seed and transplanted
Seeds per Gram: 250
Space between rows: 5 cm (3”)
Space between seeds: 0.5 cm (1/4”)
Depth: 1 cm (1/3’)
Germination: 10 days
Germination and Transplanting: 30-35
Transplanting and Harvest: 80
Transplanting Distances:
Between Rows: 12 cm ( 5”)
Between plants: 10 cm (4”)
Plants per m2: 67
pH from 5.5 to 7.0
Onions are used with garlic and ginger as the basic flavorings
added to food. They are not really roots but part
of the allium family. Because they grow above the media
they can be grown in a 6” bed grower.
Pests: Onion maggots and thrips. Onions are used in
bed growers as a companion plant to repel insects.
Diseases: Downy mildew, neck rot, pink rot, and smut.
Molds and mildew: onions can get molds and mildew.
Mold around the root is caused by extra moisture near
root. Make sure the water level is lower in the tub, or
pour nutrient in a place in the tub where it does not
wet the roots. Also, mildew can build up from stale air,
so good air ventilation is needed.
Harvest: After the bulbs have reached maturity, place
them in an old onion or orange sack. This loose netting
will allow air to flow through and finish curing
the onions. Hang the sack of onions in a protected area
with plenty of ventilation. Onions will keep for several
months if left in a dark, cooler place.

From: "Home Hydroponic Garden" by Peggy Bradley & Cesar Marulanda