Woad Leaf Harvesting – How To Pick Woad Leaves For Dyeing

Woad Leaf Harvesting – How To Pick Woad Leaves For Dyeing

By: Liz Baessler

If you’re at all interested in natural plant dyes, chances are you’ve heard of woad. It may not look like it, but in its plain looking green leaves there’s a very effective blue dye hiding. You just need to know how to get it out. If you’ve already planted dyer’s woad, the next important step in the process is harvesting the leaves. Keep reading to learn more about when and how to pick woad leaves for dyeing.

When to Harvest Woad Leaves

The color in dyer’s woad can be found in its leaves, so harvesting woad for dye is a matter of letting the leaves reach a certain size and picking them. Woad is a biennial plant, which means it lives for two years. In the first year, it focuses only on growing leaves, while in the second year it puts up a flower stalk and produces seeds.

Woad dye harvest is possible in both seasons. In its first season, dyer’s woad grows as a rosette. You can begin harvesting the leaves when the rosette reaches about 8 inches (20 cm.) in diameter. If this is the second year of growth for your plant, you should harvest before it puts up its flower stalk.

Dyer’s woad can spread very prolifically by seed, and is actually invasive in many areas, so you don’t want to give it the chance to flower or put out seeds. Second season woad leaf harvesting should include digging up the entire plant, roots and all.

How to Pick Woad Leaves

There are two ways you can go about picking the leaves during a first season woad dye harvest. You can either remove the entire rosette, leaving just the roots intact, or you can pick only the largest leaves (the ones that are 6 inches/15 cm. or longer) and leave the shorter leaves in the middle of the rosette.

In either case, the plant will continue to grow, and you should be able to get several more harvests out of it. If you pick the entire plant, of course, you’ll get fewer harvests, but you will have more leaves to work with this time. It’s completely up to you.

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Read more about Woad Plant

Extracting Woad: a natural blue pigment for dyeing and soap making

Making your own natural blue dye

Growing and extracting blue pigment from Isatis tinctoria, known as Woad. Extracted from green leaves, this natural color is used in dyeing & soap making

Originating on the steppes of central Asia, Woad, also known by its Latin name Isatis Tinctoria, has been cultivated throughout Europe and the Mediterranean for millennia. Though its seeds have been found in French Neolithic sites, the first evidence of it being used in the dyeing of cloth comes from ancient Egypt. Later evidence of Woad dyes come from Roman, Viking and Medieval sources and sites.

If I ever meet anyone who isn’t familiar with this plant I tend to refer them to Braveheart which nearly everyone has seen. Once I mention Mel Gibson painting his face blue it tends to flip a switch for people, though there’s some debate over whether the Britons ever used Woad for this purpose.

Infusing woad leaves in water around 80 degrees Celcius

It’s hard to believe that these obviously green leaves contain such a vivid blue pigment and I wonder how the first people actually discovered it. So many of our past discoveries seem to be purely accidental so I don’t doubt that it was the same with Woad. However there are quite a few steps in the extraction process which makes me wonder how on earth someone could have stumbled upon it.

To extract Woad you need to first infuse leaves in nearly boiling water – preferably soft water such as rain water. After ten minutes the leaves are removed and squeezed of any juice before being discarded on the compost pile. The resulting liquid is strained and then soda ash is added which starts the process of extraction. Soda ash is a type of carbonic acid which can be sourced from the ashes of various types of plants – it’s also commonly used as a water softener. Through a process of aeration, settling, rinsing, filtering and drying you’re left with a natural blue pigment which can be stored and used indefinitely. For more information on the process please visit Woad.org.co.uk.

Aerating the infusion with a mixer

Allowing the pigment to settle in the liquid

Recently I’ve come across a few people who have asked me about the use of woad in skincare and whether it is safe. My answer is that Woad is a non-hazardous natural product that is completely safe to handle and use externally. In fact the chemist who conducted the safety assessments for my products actually allows me to use more than ten times the amount that my soap actually contains.

Woad can also be taken internally, though I’ve never tried it myself. Used in both European and Chinese herbal medicine for at least two thousand years, compounds in Woad are said to combat certain types of cancer and anti-inflammatory diseases. Human studies from China have also shown that Woad has antimicrobial, antibacterial, antiviral and antiparastic qualities. [1]

There is also some misinformation on the internet on whether Woad will stain your skin. I can imagine the deduction work in this assumption: Since Woad is used to dye cloth wouldn’t it also colour anything else it comes into contact with? I’d like to assure you that Woad as a powdered pigment colours only the soap. It works in much the same way as mineral pigments and suspends as tiny granules only giving the illusion of dyeing the soap. To use woad as a dye, additional chemicals such as Alum and Spectralite are required to get it to ‘fix’ to the cloth or wool.

Another positive point on woad is that it breaks down much more easily and naturally than commerical oxides. This property makes this product a much more environmentally sensitive alternative to micas, oxides and other laboratory-created soap colouring agents.

In short, Woad is safe, won’t stain your skin and is a lovely and authentic natural colourant for use in soaps. I enjoy using it and growing it in my own garden and would encourage anyone else who is interested in Woad to try it out as well.

Growing and harvesting woad

Woad is a relatively easy plant to grow. It is from a mustard family. It isa biennial plant that forms leaves in its first year. Then flowers and goes to seed the next year. It’s the first-year during summertime its leaves that produce the blue dye. Although it is known to produce blue dye in the winter and second year. It does happen but rare.

To grow woad obtain some seeds. I got mine online on eBay. Do buy a few packets of seeds as germination can be unreliable. Sow the seeds in early spring or early fall. Spread them out when sowing as woad has a taproot. Therefore it does not like to be disturbed and best not to transplant too much. If it has to be transplanted do take care not to damage its taproot. Plant them apart about 30 cm apart. Grow woad in full sun and water regularly. Feed them with some manure compost and water regularly so it produces strong leaves.


Woad is ready to harvest for dyeing when it becomes establish and produces nice strong big leaves. Harvest them regularly so as to produce more leaves. It’s been in the books and web that to harvest the leaves in the morning, during July and August. Use the leaves as soon as it is harvested so that to obtain the bluest dye. It is also known some to leaves latter and still able to obtain blue dye out of it.

In its second year, once the plant starts to flower cut back the flowers and leave one or two flower stalks to seed. Once the seed mature cut them off and store seeds for sowing new plants. The seeds can be stored for several years before they lose viability. It is also possible to harvest the seeds for the dye pot by using mature seeds. This is done by cutting the stalks and removing seeds.

Thank you for reading and dropping by. Do have a look at my other blog post on preparing indigo for fabric dyeing.

Adventures in Natural Dyeing: Growing Woad

Cooler temperatures and cleaning up the end-of-season garden inspire us to plan for next year’s growing season. Do your plans include a dyer’s garden?

Using both the indigo method and traditional dyeing methods brings an amazing array of colors from woad.

Cooler temperatures and cleaning up the end-of-season garden inspire us to plan for next year’s growing season. Do your plans include a dyer’s garden? Some plants used for natural dyeing should come with a warning, and woad is one such plant. In this excerpt from Spin Off Summer 2018, contributor Gayle Vallance shares the basics about cultivating this problematic plant.

Woad (Isatis tinctoria) is a hardy member of the Brassicaceae (also called Cruciferae) family. It is easily cultivated in any reasonably temperate climate (zones 3 to 8), but it requires fertile soil and plenty of sunshine for greater dye production. It is a biennial, forming a rosette of leaves in its first year and a flowering stalk up to 4 feet (1.2 meters) tall in the second. The flowers produce thousands of seeds that detach easily when the pods turn purple. Seeds need only be collected every couple of years, since they store well in a jar or freezer. You can test seeds for potency by placing them onto wet paper a violet color cast on the paper indicates a higher indigo content.

A close-up of a woad plant. Photos by Gayle Vallance

Plant the seeds ½ to 1 inch deep when the soil is warm. They germinate in 10 days, and the plants should be thinned to 8 to 10 inches apart. Spread straw mulch between the rows to retain moisture and discourage weeds. You can harvest leaves every 3 to 4 weeks between June and August.

In North America, woad is considered a noxious weed, and therefore it must be controlled. A dyer should dig out the plants at the end of the first growing season, remove the spreading roots, and leave only one plant to produce seeds the following year. Pull seed stalks before the seeds are fully ripe and store them to ripen in a closed paper bag. Check local, state, and federal agricultural regulations before growing woad, which may be quarantined, prohibited, or targeted for eradication in your area.

Gayle Vallance earned a Master Spinner Certificate at Olds College, Level I of the Certificate of Excellence (Spinning) through the Handweavers Guild of America, and the basic level of the master weaver program through the Guild of Canadian Weavers. She teaches at conferences around North America.

Woad seeds can be purchased from www.wildcolours.co.uk or from www.richters.com in Canada. Richters cannot ship seeds to California, Idaho, or Montana in the United States or to Alberta, Canada. Consult your local extension office before attempting to grow woad. To read more about using woad for natural dyeing, download the Summer 2018 issue ofSpin Off. Plus to learn more about the ins and outs of natural dyeing, download a copy of our free eBook,Guide to Dyeing Yarn: Learn How to Dye Yarn Using Natural Dyeing Techniques, gathered from the pages of _Spin Off magazine.

Featured Image: Using both the indigo method and traditional dyeing methods brings an amazing array of colors from woad.

Watch the video: Organic Fabric Dyeing with Natural Dyes in Industrial Scale