Production Requirements
Soil Types: Well-drained loam, silt loam or clay loam soils are preferred
Soil pH: >5.6
Preferred Rotational Crops: Corn, cereal crops
Minimum Soil Temperature: 3°C
Optimum Air Temperature: 10°C–27°C
Earliest Planting Date: Early to late April
Required Growing Season: 90–115 days
Flax is a versatile crop that has been an ingredient in oil-based paints, protective coatings, linoleum, printer’s ink, soaps, industrial lubricants and as a salt-resistant coating for concrete. Fibre fax and the health benefits of flaxseed oil in a variety of foods have diversified the market. Flax seed contains 35%–40% linseed oil. After oil extraction, the remaining linseed meal is used as a livestock protein supplement, which averages approximately 35% protein content.
The guidelines provided in this section refer to oilseed-type fax. Production requirements for fibre fax may be different. More information on fibre fax in Canada is available from the Flax Council of Canada website at www.faxcouncil.ca.
Tillage and Seedbed Preparation
A firm, level seedbed for good seed-to-soil contact is best for rapid, uniform emergence. Packing the soil before and/or after planting is suggested. Crop success has been better where there is minimal crop residue. Use rotations similar to those for cereals or legume forages.
Variety Selection
Variety selection will be different for oilseed and fibre purposes. Until now, oilseed varieties have been the only commercially produced fax grown in Canada. Oilseed varieties are grown specifically for the oil extracted from the seed.
Planting
Flax is planted using similar equipment to cereals, in narrow rows 15–20 cm (6–8 in.) apart. Using a grain drill results in a more uniform seeding depth and plant emergence than broadcast seeding. Seed to a maximum depth of 2.5 cm (1 in.), as there is likely to be adequate soil moisture to stimulate germination in the spring. Deep seeding can significantly delay emergence, particularly during cool, wet springs. Optimum seeding rates are 35–50 kg/ha (31–45 lb/acre). Seeding rates higher than 50 kg/ha along with high nitrogen rates can lead to excessive lodging, making harvest difficult.
Early planting results in higher yields and easier harvest. Seedlings can withstand moderate frost. Well-drained loam, silt loam or clay loam soils are preferred. Flax plants have a relatively short taproot which makes plants susceptible to moisture stress on light textured soils.
Crop Development
Flax is an annual plant with a short taproot from which fibrous roots grow to depths of approximately 1.2 m (4 ft) in light soil. The height of the crop varies from 45–91 cm (1.5–3 ft), depending on growing conditions. In thick stands, only a main stem develops but in thin stands four or more tillers can be produced. Flowers may be white, blue, pink or violet, depending on variety. Flowers open late in the morning and drop by early afternoon. Flax flowers for 3 weeks with sufficient fertility. Flax flowers can self-pollinate, but insects can cross-pollinate between varieties. A seed capsule produces up to 10 seeds. Flax seed produces a gel around the seed once they are exposed to water. This gel gives the seed a sticky texture when wet which could make handling more difficult.
Fertility Management
Flax nitrogen needs are the same as for mixed grain (45 kg/ha or 40 lb/acre in southern Ontario and 70 kg/ha or 62 lb/acre in northern Ontario). Excessive nitrogen will make the crop lodge. A soil test is the best method of determining phosphorus and potassium requirements. See Table 7–2, Phosphate guidelines for buckwheat and fax and 7–3, Potash guidelines for buckwheat and fax. Flaxseed is susceptible to fertilizer burn; therefore, broadcast all fertilizer.
Harvest and Storage
Harvest
Flax typically yields 1,200–2,000 kg/ha (1,100–1,800 lb/acre). Flax can be harvested by either direct combining or by swathing prior to combining.
Direct Combining
Since fax will continue to produce new vegetation throughout the season, a pre-harvest dessicant will be required if the crop is being direct combined. When direct combining, use batt reels to prevent wrapping of fax plants with pick-up reels. Consult the product label for specific directions on pre-harvest applications.
Swathing
Swathing, then combining, results in drier seed than with direct combining. Swath when approximately 90% of leaves have fallen and the seeds have turned dark brown. Flax does not shatter as easily as other grains. Swath weedy crops to allow weeds and straw to dry out before harvest. Leave 15 cm (6 in.) of straw stubble to keep windrows of the ground. Under good drying conditions, the crop can be combined 3–4 days after swathing.
Keep combine and swather cutter bars and guards sharp to reduce the accumulation of immature fax straw on the knife. Combine fax when the straw is dry and seeds rattle in the boll. Early-sown fax is easier to thresh than late-sown fax because it matures under the dryer conditions of late summer.
Adjust the combine to narrow the clearance between the cylinders and concave to about half that of cereal grains and slow down the cylinder. Set fan speeds fairly low since seed is easily blown out the back of the combine. A clean-looking sample in the bin is an indication that too much seed is being blown out. It is not unusual to have dockage levels of 5%–10%. Be sure to plug any holes in the grain tank, augers and elevators, because fax seed is extremely slippery and will flow through small holes.
Storage
For storage, fax should be less than 10.5% moisture. Higher moisture percentages will incur a drying and shrinkage charge. Flax spoils quickly; therefore, proper storage is critical. Drying and cleaning prior to storage can help reduce the amount of dockage.
Straw Removal
Oilseed varieties of fax straw are not suitable for linen production due to the short fibres in the stem. Flax straw is slow to rot in the soil and is usually a problem for tillage operations following harvest or in the following crop season. Make every effort to find a use for the straw so that it can be taken of the field. Flax straw is sometimes used in feedlots as bedding. The straw has also been used as a fuel source for burning in large furnaces.
Weed Control
Flax is a poor competitor with weeds. It does not form a dense canopy to shade the ground, so weeds have the opportunity to establish. Perennial and difficult to control weeds are especially problematic since herbicide options are limited. Plant fax in relatively weed-free fields, whenever possible.
For herbicide options, see OMAFRA Publication 75, Guide to Weed Control.
Insects and Diseases
Insects and diseases are typically not a concern in fax production.
Feature Image: Flax Council of Canada