How to Plant, Grow, and Care for Flax

The fibers of this ancient grain have been used for millennia among Roman, Egyptian, and Mesopotamian peoples. Today, people grow flax plants for commercial and home use. 

There’s so much to gain from working with flax. While you may not be interested in the lengthy process of making linen fabric, flax flowers and flax seeds are well worth the effort it takes to grow them. And once composted, your flax remnants can improve your soil, too. 

The whole organism is used among commercial growers for fiber production and feeding livestock. The linseed oil from flax seeds is used in staining wood, and creating paint pigments. With multiple ornamental varieties to choose from, it’s no wonder people grow it in their home garden. 

What is Flax?

Flaxseed (Linum usitatissimum), also known as common flaxseed or linseed, is believed to have originated in upper Paleolithic Georgia. It’s there in Dzudzuana Cave that fibers thought to be 30,000 years old were found.

Egyptian paintings depict production and common flax alongside deities. Pharaohs were wrapped in linen (or flax fibers) in the mummification process. Romans used the fabric for ship sails. These grains made their way to the Americas with the first colonial settlers who viewed them as central to their lives. 

Characteristics

Common annual flax has a round stem that reaches up to four feet tall and begins growth in early spring. The pale green leaves are lance-shaped and grow from the stem and branches alternately.

Their ‘true blue’ self-pollinating flowers are funnel-shaped with five petals. They bloom in late spring to late summer, and die away in one day, revealing a pea-sized capsule that contains 10 distinctly separated seeds.

When the pods dry they turn golden, ready for harvesting. These small, flat, and brown to golden seeds gel together when wet, much like chia does. In large masses where conditions are right, flax plants self-seed and return the following spring. 

Uses

Culinarily, the seeds are used whole, ground into powder, and pressed into oil. Linseed oil is the base for many oil paints and is also one of the most popular furniture and wood oils. The remaining meal leftover from linseed oil production is used to feed livestock and bulk up commercially sold animal food.

The flax plant’s blue flowers are edible too and are used in confections as decoration. The flower is used to make dye. The entire organism is processed and made into fiber linen. 

Flax has medicinal uses too. It’s also grown commercially to treat osteoporosis and provide support to healthy blood glucose levels. Linseed tea with lemon and honey is prized by herbal healers.

The seeds accompany delectable whole-grain bread, crackers, and tortillas, adding fatty acid to meals. Ground nutritious seeds are also great as an egg replacement for vegan diets. Just one tablespoon of flax seeds or flax meal packs a meal full of nutrient content. 

Planting

Before adding flax seeds to the soil, soak them. When they develop a mucosal casing, spread them on the surface of the soil, either directly in the garden or in a flat. One tablespoon will cover a ten square foot (or one square meter) plot of land.

If you’re sowing directly, remove weeds and sow in early spring six to eight weeks before the last frost. For flats, carefully transfer the young seedlings into your garden in one mass, adding dirt to level the area.

Because flax seedlings can get root bound, exercise caution so as not to disturb the root ball. Gently rake directly-sown seeds into the garden. The spot you choose needs full sun, with moist, loamy, fertile soil that is well-draining.

Flax will grow just fine in a well-placed and well-filled container too. Use a pot that can accommodate the taproots. A large planter will give you room for a flush of flax flowers, and a decent harvest too.

How to Grow

Once you’ve sown flax, you’ve won at least one-third of the battle. Let’s cover the basics of caring for this laid-back bloomer. 

Light

Flax likes full sun, with at least 6 to 8 hours of direct light exposure per day. Shady areas will negatively impact flowering and production. If you don’t have the right spot to plant in the ground, plant in containers to take advantage of sunny areas.

Water

Water regularly, and keep the soil moist around flax. Apply water daily in dry weather at the base, wetting the roots and not the foliage. Once they are established, they won’t need much water. In the growth period, water every few weeks.

This drought-tolerant grain doesn’t like wet feet. So if it rains heavily in a season, don’t add extra water. Use soaker hoses or drip irrigation when water is needed. 

Soil

Common flax enjoys fertile, loamy, well-drained soil. It is tolerant of other soil types but thrives in loam. Do not grow flax in heavy clay.

To prepare the soil, amend the earth or your average garden soil with a little bit of well-rotted compost or manure. If you’re working with clay, add more amendments. The optimal pH for growing flax is between 6.0 and 7.5. 

Temperature & Humidity

This plant thrives in USDA hardiness zones 5 through 9, in a temperature range of 65°F to 70°F (18-21°C). It can be grown across zones 2 and 11, though. Flax will grow and bloom in cool weather best but can withstand lows in the mid-20s, and highs in the 90s for brief periods(~-7-32°C). At temperatures above 100 degrees, flax decreases pollen production.

If you expect a snap freeze in spring, grow flax plants under frost cloth. Excessive heat reduces seed development. A shade cloth could assist in seed production in high heat.

Fertilizing

Mature plants don’t need any fertilizer. However, they appreciate a thin layer of well-rotted compost or other organic matter applied to the soil surface at planting. Reapply this annually in early fall and spring. This gives self-sown flax and perennial flax a little boost.  

Maintenance

Some guides recommend cutting perennial flax back in its fifth year to prevent legginess. Most scientific studies, however, suggest practicing crop rotation with a grain crop of flax every three years.

If you want to control their spread, remove seed heads from the planting area before more flowers appear to prevent any further germination. Remove any brown and diseased leaves on the plants in the growing season to keep the short-lived flowers healthy. This way, they’ll produce enough seeds for you to enjoy. 

Propagation

Most home gardeners know about propagating flax by seed. This is an easier propagation method. Either allow the flax flower to bloom, die, and for seed pods to form. Then allow the seed capsules to fall to the earth. The flax seed will then germinate on its own.

You can assist in flax production by removing the seeds and sowing them in an area with similar characteristics to the one from which you just extracted seeds. See the planting section for more details.  

Another way to rotate your plants is to divide them and carefully proceed with planting them elsewhere. Dig up the stems and entire root system of the section, remove weeds from the new planting area, prepare the soil, and add your plants to the new section.

Harvesting  

The blue flowers of flax should be picked and used immediately because they bloom and die in just one day. Seed pods are fully mature and ready when the flowers have bloomed and died and you can hear the seeds within the pod when you shake them.

After the blue flowers have died, look at the pods. If they are golden in color, shake them for the seed sounds.

To harvest, grab a bunch of stems near the base, and cut them with a sharp knife. Then, shake the stems over a clean sheet or cloth. If seeds come out of the pods, they are ready for post-harvest processing. If not, dry them in an area with good air circulation for a few weeks.

Thresh the pods, and sift the plant matter from the seed. Make linseed oil by pressing the seeds, or by boiling them in a slow cooker. 

If you’re using the plants for fiber, bind the stems at the center and stand them in direct sunlight to dry. This is how growers prepare flax grown for a commercial crop of fiber.

When the flax is brittle, they’re ready for the retting process, where the stems are laid out in a thin layer and dew-retted. Turn them every week testing the stems with each turn. When the fibers separate from the stalks easily, they’re ready. 

Storing

Store fresh seeds in an airtight container for one to two years at room temperature or in the freezer. In the refrigerator, they keep for one year. Ground seeds expire at six months in the refrigerator or freezer. At room temperature, flax seed meal keeps for a couple of days.

Keep flaxseed oil in an airtight container in the refrigerator for up to one year. In the freezer, store it for 6 months. Use flax flowers right away, or dry the flower and store it in an airtight container. Raw material fiber kept in cool dry conditions lasts for an indeterminate time. 

Common Problems

Flax has quite a few pests and diseases, and a few growing problems. Let’s discuss what to look out for, so you can enjoy linseed oil or flax fibers at harvest. 

Overwatering

Since it’s drought-tolerant, underwatering isn’t often an issue. Overwatering can weaken the root system making the plant more susceptible to disease. So can a lack of drainage. Since it’s a fast grower, it’s difficult to remediate these issues and you might have to try again next season. 

Incorrect Temperature

Too much heat will cause lower yields, and too much cold causes stunted growth. A snap freeze will damage the leaves. If there is a small amount of cold damage present, remove damaged leaves and let the plant bounce back. 

Shade

Plants in too much shade won’t reach peak performance either. Indoors, supplement with a grow light. Outdoors, try to divide and move the plant in a sunnier location. Avoid disturbing the roots too much as they’ll experience transplant shock. If you’re careful, the plant can return from shock with gentle and proper care.  

Worms

Army cutworm, bertha armyworm, pale western cutworm, and red-backed cutworms all love to snack on the leaves of common flax. If you notice them on your plants, you may notice they consume only the green parts of leaves. As only the vasculature of leaves remains, they take on a lace-like appearance.

All armyworms and cutworms are prolific and easily devastate a crop. Thankfully, there are several ways to control them. Hand pick them. Neem oil diluted in water and sprayed all over the plant is one way to keep them away. Alternatively, try Bt spray (Bacillus thuringiensis). Pyrethrin can handle severe pest outbreaks as well.

Wireworms are the larvae of click beetles, and they feed on the ungerminated seeds and roots of your plants. In infestations, they prevent the emergence of sprouts. Prevent them by aerating the soil before planting.

Bury potatoes on a stick 2 to 4 inches deep in the earth with the stick poking out so it can be removed. In a week, take the potato out and there you’ll have wireworms feasting. Throw them out. Beneficial nematodes are a great measure for reducing wireworms in the soil before planting too. 

Grasshoppers

Grasshoppers feast on all parts of the plant above the soil. Spray kaolin clay in water on every part of the plant to keep them off. Neem oil spray is another option. Diatomaceous earth on the soil and plants works too. If worse comes to worse, spread the grasshopper-specific pathogen Nosema locustae via a broadcasting tool. Grasshoppers will eat the bait and die. 

Leafhoppers

The aster leafhopper can be devastating to plants. Leafhoppers suck the sap from leaves and spread diseases in the process. They shelter in garden debris left behind, so keep your planting area clear. Insecticidal soap applied every couple of days will prevent them from laying eggs on your plants. Kaolin clay powders work too. In the event they just won’t go away, try pyrethrin spray once every 7 to 10 days. 

Aster yellows is caused by a phytoplasma injected into plants by leafhoppers. Symptoms include the yellowing and deformations of the tops of plants, including the flowers. Infected flowers won’t produce seeds. Seed early to reduce the spread of phytoplasma by leafhoppers. Sadly, there is no known organic control. Remove affected plants and destroy them. Do not compost plant materials infected with aster yellows.

The oat blue dwarf virus is also spread by leafhoppers. Colloquially referred to as “crinkle”, this virus causes leaves to crinkle, and the plants may experience stunted growth or reduced yields. There are no known controls for this viral pathogen beyond preventing leafhoppers from reaching your crop. Destroy infected material so that the virus will not spread further.

Rust

Rust is a fungal disease that overwinters in the detritus of flax debris leftover from last year’s crop. It is caused by the Melampsora lini fungus and presents as bright orange pustules on flax leaves, stems, and bolls. It proliferates in humid and cool nights in a garden. As they progress, the spores on stems turn black.

Copper fungicide has some effect against rust, but prevention is better than treatment. In preparation for growing flax for fiber or seeds, remove any weeds and debris. Thin plants after they germinate to promote better air circulation. Remove damaged foliage as it crops up. If your plants get severely infected, remove them and dispose of the entire plant. 

Fusarium Wilt

Fusarium wilt is another fungal ailment caused by Fusarium oxysporum f.sp lini which invades from the roots upward. The organism interferes with water and nutrient uptake, especially in the seedling phase of growth. The dying plants have ashen roots, and a characteristic “shepherd’s crook” appearance.

By rotating crops, you can prevent infections of fusarium wilt from spreading to other areas. Some forms of mycorrhizae or soil bacteria are proving useful to combat Fusarium fungi. You should remove any plants with fusarium wilt and throw them away to prevent spread.

Pasmo

Pasmo, caused by the fungus Septoria linicola, occurs at the soil surface and above parts of the plant. Infected leaves display brown lesions, and stalks display brown and green bands.

This infection will make it impossible to use the plant for fibers. Use cultural controls listed in the two previous paragraphs to prevent fungal disease. Early seeding also helps. There are no known natural controls for pasmo. If your plant is infected, remove and dispose of it.  

Blight

Seedling blight is caused primarily by the fungus Rhizoctonia solani. Before seedlings have a chance to get started in spring, they turn yellow and then wilt and die. Look for gaps in your planting areas to determine if seedling blight has hit.

To prevent seedling blight, apply a copper fungicide spray in dilution every 7 to 10 days to support healthy growth. If a couple of weeks of application doesn’t work, remove the seedlings and dispose of them. 

Powdery Mildew

Powdery mildew is caused by multiple fungal strains, particularly on flax the fungus Oidium lini. It appears as white powdery masses on the leaves. Thin your newly germinated seedlings to promote air circulation.

Neem oil or a copper fungicide can be used to treat light infections, and neem oil works as a preventative spray as well. Remove damaged leaves as needed. Water at the root level. You can still have a fiber or seed harvest if the infection isn’t too bad. 

Frequently Asked Questions