Seed rate: average figures are 40 kg/ha for oil varieties, 120 kg/ha for fibre
varieties. However in order to achieve the optimum plant population in oil crops
oil varieties.
Seed spacing: 1000–1300 seeds per square metre are sown, in rows 15 cm apart for
oil crops, closer together for fibre crops.
Depth: 2–2.5 cm, in a fine seedbed.
Germination: seed can remain viable for 5–10 years if stored dry and cool.
GROWTH CONDITIONS
Day length: there are both long-day and day-neutral varieties of linseed.
Growth period: 120–150 days.
Temperature: linseed is a cool weather crop, and is sown in late autumn in regions
with mild winters and hot summers. Seedlings may be killed by a heavy frost, which
also reduces yields if it occurs at flowering. During and after flowering, about 32°C
is the maximum. Seed of linseed should be stored at less than 10% moisture.
Rainfall: oil varieties can grow with only 300 mm, but are normally grown in 450–
750 mm/year rainfall areas, or with irrigation. Fibre varieties need more water than
oil ones.
Rotation: should not be grown on the same land more often than every five or six
years. In a rotation, linseed can substitute for cereals, such as after legumes or
pasture. If weeds can be controlled it is a good first “pioneer” crop on newly cleared
land.
Pests: rarely a problem, but yields are sometimes reduced by grasshoppers,
cutworms, armyworms, chinch bugs, stinkbugs and flaxworms.
- Flax Fleabeetle—this can completely decimate the crop, as the seedlings are just
emerging. Control is with seed dressings, insecticide and/or later (warmer) planting
for more rapid seedling emergence.
Diseases: three of the most troublesome, all caused by fungi, are: - Flax Wilt—stems of young plants turn brown and dry up, normally in small areas
all over the field, or on individual plants. Worse when linseed has been grown for a
long time on the same land. Control: crop rotation, but as spores can remain viable
in the soil for 25 years it is better to use resistant varieties. - Flax Rust—bright orange or red spots appear on all aerial parts just before
flowering which become black and shiny. Worse in wet conditions. Control is with
seed dressings, crop rotation, or, best of all, resistant varieties, though these may not
resist all races of the fungus. - Pasmo—leaves have dark brown patches which then spread to the stem where the
seed (treatment is not effective), destroy infected plants, crop rotation and resistant
varieties.
- Botrytis, Mildew, Alternaria and Sclerotinia (see Horse Bean) can also be
damaging.
There are also two virus diseases—Aster Yellows and Curly Top - both are
transmitted by leafhoppers, which can cause some loss of yield.
these may use 80–100 kg/ha. 1000 seeds weigh about 3–4 g for fibre varieties, 7 g for
patches are brown or black. Occurs above about 20°C, spread by rain. Control: clean