Monday, 14 May 2012

Flax (Linum usitatissimum)

Flax (Linum usitatissimum) is an annual plant from the Linaceae family. It is also known as common flax.

Flax has been used throughout the world for food (seed, oil) and fibre (linen, paper) thousands of years. Although there are around 220 different species of flax, L. usitatissimum is the one usually grown commercially

Pretty blue flax flower growing in Kent

Flax seed/oil

Flax is also called linseed and is an edible seed and oil. It is a good source of Omega-3 essential fatty acids, lignans and soluble and insoluble fibre. It is a popular raw food and is commonly used as an ingredient for crispy flax crackers. Two types are usually available in the UK: a brown seed and a yellow or golden seed which is much lighter in colour. See photo below.

The oil is also used in paints, linoleum flooring and as a wood preservative which is safe and natural for indoor and outdoor use. There are two types commonly sold diy/hardware stores; raw linseed and boiled linseed. The raw linseed is more natural but takes longer to dry. Boiled linseed dries more quickly, is darker in colour, may have added chemical driers and is non edible. It shouldn't, therefore, be used on things like wooden bowls.

Flax seed (shop bought)
Flax Fibre

The flax plant also produces a fibre which can be spun into a yarn or made into paper. The yarn can be used for knitting, to make string or woven to make a fabric called linen. Flax is a perfect alternative to cotton which cannot be grown commercially in the British Isles.

Buying seed to grow

Buy edible organic seed from a wholefood store or supermarket as these are the cheapest. Mail order plant catalogues sell small packets of seeds for an extortionate price so making the whole process of growing seed for home consumption a non starter. We've been growing these organic seeds for years and they are always absolutely fine.

The flax grown for the edible seed is usually a short straw which yields little fibre. If requiring fibre for spinning or weaving choose the long straw fibre varieties. A long stemmed variety called 'Marylin' can be bought from Wild Fibres. We have the seed but I'm afraid we haven't actually grown these yet although we often spin flax. It is also possible to get seed from the long straw varieties but it doesn't produce as much seed.

Growing flax seed

Flax is easy to grow in the British Isles since it prefers a moist cool climate. Sow seeds in March outside where they are to grow using about 13g per square metre. We usually sow in rows about 10cm wide and 2.5cm deep leaving about 40-50cm between rows. Plants grow to about 75 cm tall. The pretty blue flower only lasts for about 3 weeks and seeds can be harvested from June onwards. The round seed heads formed after flowering go from soft green to a papery brown as they mature producing several seeds to each pod. Flax plants are robust and generally crowd out other plants.

Harvesting and storing

Allow the seed head to mature before harvesting them. Just before harvesting ensure a few dry warm so the plants are nice and dry. Grab a handful of stems and pull them up. The root is fairly small. Shake the soil off, tie with string in bundles and hang up for another week or so to further dry out. Sometimes we lay them out on the ground in the sun if it is very hot and dry. Once they are properly dry, the seeds can be shaken out. Gently rub and shake the heads and the seeds will drop out together with lots of bits of papery chaff.

To remove the chaff, we lay the seeds out on a large tray with a lip or low sides in a windy place for a day. It is usually all be blown away by the evening. Further dry the seeds off in a dehydrator at the lowest setting (20°C or less) and store whole in an airtight container in a cool dry place. It can be stored for up to three years like this. Don't store seed ground down to a fine powder as it will go rancid quickly.

Bundles of flax ready to hang to dry out

Raw edible parts

The raw edible parts of the flax plant are the seeds. The seed can be used whole, ground down to a powder or sprouted. It is a mucilagenous seed and should be sprouted in a clay dish sunk in a bowl of water. Seeds can also be grown on a wet paper towel or compost and harvested as micro greens. The health benefits of flax seed have been widely reported.


There are a couple of issues with flax that people should be aware of. However, these issues shouldn't discourage anyone from using flax.

This is what the Flax Council of Canada say:

"Illness from eating too much uncooked flax seed, in a diet with little variety, can arise because flax seeds are among 12,000 plant seeds, such as almonds and cassava, which contain moderate amounts of natural compounds called cyanogenic glucosides. These glucosides occur naturally in many plants ... In an unbalanced diet, one which is based mainly on a plant containing cyanogens, a concentration of the cyanogenic compounds can build up in the body, leading to unpleasant and, on occasion, life-threatening reactions."

Eating 50g of flax daily shows no increase in glycoside buildup in the body and is fairly safe. Cooking, something which most of us reading this probably won't do, also renders the compounds harmless. Cyanogenic glucosides found in flax can inhibit the uptake of iodine. Therefore, anyone taking flax seed regularly should ensure their intake of iodine is good. Kelp is a good source of iodine for those on a raw food diet. It is bad to have too little iodine but equally as bad to have too much so don't overdue it.


  1. What about the small leaves that are all over the stems? Can I eat those?

  2. if I plant the edible flax seeds I have will they produce the pretty blue flowers?

  3. Yes..I did small plants came in my kitchen garden...