Seeding
Flax usually does well on types of land suitable for wheat. It grows best on soils with high water-holding capacity and good inherent fertility. However, one disadvantage of heavy soils is their tendency to crust after heavy rains and interfere with the emergence of the seedlings. The use of zero tillage can greatly alleviate this problem. Flax does not thrive on sandy soils unless a large supply of moisture is available. Imperfectly drained soils may result in yellowing and stunting of flax. However, flax will usually outgrow this yellowing.
Poorly drained land, or land subject to excessive drought or erosion should not be sown to flax. Flax is moderately tolerant to salinity, provided that fertility levels are suitable and adequate moisture is available during germination.
Choice of Seed
Use good, preferably certified, seed of a recommended variety. Certified seed is tested to ensure minimal weed content, genetic purity and good germination. Certified seed consistently yields better than cleaned seed and produces a higher net return from the crop. If farm-produced seed is used, it should be tested for germination, vigor and disease and thoroughly cleaned to remove weed seeds.
SaskSeed® Guides – Saskatchewan Seed Growers’ Association
Seed Quality and Effect on Plant Stands
Reductions in stand must be expected when using untreated, damaged seed. Damaged seed is prone to decay by soil micro-organisms, and the seedlings that do emerge are weak and prone to develop seedling blight. Resulting stands will be poor, uneven, low yielding and lacking in vigour.
Seedlings produced from damaged seed may germinate very slowly and may be weak or show a variety of abnormalities. Common abnormalities include injured root tips, broken or cracked cotyledons, split hypocotyls, twin radicles, radicles trapped inside the seedcoat, and roots that are blunt, broken, long and spindly, or gnarled and distorted.
Seedbed Preparation
Method of Seeding
Flax should be sown shallow, 2.5 to 4.0 cm (1 to 1.5 in.) deep, with a drill that places the seed at a uniform depth in rows 15 to 20 cm (6 to 8 in.) apart. Recent research has shown that up to 30 cm (12 in.) row spacing in zero tillage is acceptable. Depth of seeding trials at the University of Alberta have shown that seeding depths greater than 3 cm (1.2 in.) result in significant reductions to emergence and yield.
The most satisfactory results are achieved by using a drill equipped with press wheels which firm the soil around the seed. If a drill does not have press wheels, a soil packer may be drawn behind the drill, or the field may be packed in a separate operation.
The effect of pre-seeding tillage in terms of the type of implement, the depth of tillage and the effect of packing, either before or after seeding, has not been clearly defined. The same effect was noticed with both pre-seeding packing and post-seeding packing. As a general rule, pre-seeding packing was beneficial even to land that also had post-seeding packing.
Rate of Seeding
Seeding rate should be adjusted according to size of seed, germination percentage, soil fertility, or weediness. Generally, seeding into warm soils, as early as possible at a rate of 50 lb/ac will help achieve the optimum yields. Expect a 50-60% seedling emergence rate.
According to Manitoba Crop Insurance, yields are not significantly affected by reduction in plant stands from 400 to 300 plants/m2 (40 to 30/ft.2), but yields generally tend to drop off as stands drop below 300 plants/m2 (30/ft.2). However, even at plant stands as low as 100 plants/m2 (10/ft.2), yields were reduced only about 20%, as extensive tillering compensated for the lower stands.
Higher seeding rates may be required for varieties with a yellow seedcoat particularly if seed treatment is not applied. Excessively high seeding rates should be avoided where lodging may be a problem.
Reseeding
If seedling stands are thin, a decision must be made whether to reseed or not. Flax seedling emergence is sometimes poor due to damaged seed, soil crusting, seedling diseases, adverse weather conditions, deep seeding, herbicide injury, or other reasons. Generally, yields are lower the later the seeding date, and lower because of loss of soil moisture from additional tillage. The added costs of reseeding must also be taken into account.
Seeding Date
Early Seeding
Early seeding of flax generally produces the best results, for flax is seldom damaged by light spring frosts. Plants just emerging are the most tender, but can withstand temperatures down to approximately -3°C (27°F). After the seedlings have passed the two-leaf stage and are hardened by exposure, they can withstand temperatures as low as -8°C (18°F) for a short time without damage. Unlike cereals, where the growing point of the seedling is protected under the soil surface, the growing point of the flax seedling is fully exposed above the ground and is more vulnerable to frost.
Moderate temperatures and ample soil moisture during flowering and seed development favour high yield, high oil content and high oil quality. Such conditions are more likely to occur with early seeding. As well, seeding in mid-May generally results in somewhat less lodging. High quality straw for fibre is also more likely to be obtained when flax is seeded early.
Late Seeding
Late seeding of flax often results in much lower yields. Tests in Manitoba showed that compared to early seeding in May, a delay of seeding to June 1, June 10 and June 20 resulted in respective yield reductions of 7%, 29% and 52%. Late seeding also reduces oil content and seed size. Because green stems and second growth are more prevalent in a late-seeded crop, harvesting is more difficult.
However, a delay in seeding of flax may be necessary if herbicides are not used to control early starting weeds such as wild oats, or when drought or excessive moisture have delayed field work. When seeding is delayed until after June 1, only early maturing varieties are recommended because of the risk of fall frosts. Flax varieties differ in their performance under conditions of late seeding.
Seed Varieties
Flax belongs to the genus Linum, one of 10 genera in the family Linaceae. The genus contains more than 100 annual and perennial species. Cultivated flax belongs to the species L. usitatissimum, and its varieties are of two types:
- Oilseed flax, grown for oil
- Fiber flax, grown for fiber
Oilseed Dominance and Fiber Revival
In Canada, at present, oilseed flax is the main commercially produced crop. But there is a growing trend back to natural fibers for both industrial applications and textiles. This trend will only continue as pressures increase to produce materials that are recyclable or decomposable.
As a result, Western Canadian businesses are realizing the value of flax straw, and are developing technologies to handle oilseed straw and produce fiber from it for industrial purposes. The extraction and processing of fiber from existing flax straw residue and the dedicated planting of fiber flax will create new production and value-adding opportunities for Western Canadian flax producers.
SaskSeed® Guides – Saskatchewan Seed Growers’ Association
Priorities for flax breeding are shorter straw, herbicide tolerance, and higher yields.
