Colouring Soap Naturally: Woad & Madder Root


When making soap I like to keep the ingredients as natural, local and earth-friendly as possible. I generally choose to use essential oils rather than fragrance oils and try to source local products such as rapeseed oil and herbs. Though one of my greatest challenges is finding natural ways to colour my soaps without using artificial ingredients.

Conventional soaps are coloured with an assortment of chemicals – even some which are coloured “naturally” are often tinted with pigments such as oxide powders which are created in the laboratory rather than mined from the earth. I’m not sure which one of those sources is worse though! Other conventional colouring methods include the use of liquid dyes, micas and even food colouring – all of which can produce lovely soaps but are not necessarily ingredients you want to put on your skin.

There are lovely herbal and flower infusions (teas) that can help give colour to your soap base though: I use goldenrod and calendula for yellows and alkanet for violets. Honey added into your lye water can give a warm camel brown and chai tea leaves can bleed into beautiful brown specks throughout your bars. But the biggest challenges for me are are blues and reds.

This week I’ve experimented with two new natural colours which haven’t quite given me the tints I was originally after but still led to shades which I think are beautiful. The two new ingredients are woad and madder root powder.

Woad and Madder Root powders

Woad has been used for hundreds of years in the dyeing of cloth and wool and even in native British tribal decoration. Remember when Mel Gibson painted his face blue in Braveheart? That’s woad! It keeps secret its vibrant blue personality as a plant though – it looks rather like goldenrod and extracting the blue powder is a time-intensive process. Even so, a textile artist in our allotment grows some on her plot and I’ve already purchased seeds to grow my own next year. For the soap, I added about 1/8tsp of woad powder to a 400g recipe which uses oils that are primarily yellow. Though I’d hoped to get a blue out of that I was instead rewarded with a gorgeous green-blue – obviously due to my oil colour. The soap that I allowed to go through gel phase turned out much deeper in colour than the non-gelled but I think I can find purposes for both shades. To get a more blue colour I imagine that I’ll just need to up the amount of woad powder.

Madder has also been traditionally used in the dyeing of wool, but in achieving a crimson red. I have some seeds for this plant as well but am a wee bit hesitant about sowing it in my garden due to tales of its invasive habits. The roots of the plant are what provide the colour and when ground up they can either be used to infuse oils or be added in to the soap recipe directly. I opted for the second method in my experiment and ended up with a soft feminine pink for the un-gelled soap and a deep salmon colour for the gelled. This time I used 1/4 tsp of the powder and added it to the soap before trace. Though the un-gelled soap was a bit sticky in getting out of the mould, if I’d have left it another day or two it would have come out whole.

I’m quite happy with the results of both these natural ingredients and will definitely be adding them to my must-haves for soap making. If you come across any and want to give it a go I’d love to hear about your experiences as well.

Woad and Madder plants

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Tanya from Lovely Greens shares DIY ideas for making natural soap, beauty products, and items for the home and garden. Passionate about the 'Grow your own' movement she also shares organic gardening tips and green living ideas. Find her line of handmade bath and beauty products at

20 Discussion to this post

  1. Those are amazing!! 🙂

  2. Dani says:

    LOL – now I have to find out if woad and madder seeds are available here… 🙂

    Love the colours of your soap!

  3. What a fascinating post Tanya. I have never tried anything like this but I find it interesting that even soaps labelled as ;pure' may have chemicals in them. The farmer has quite a sensitive skin so he has to be careful what he uses for showering.

  4. A very creative friend grows woad on her allotment and gave me some seeds. I've yet to grow them as I'm not sure what I would do with the plants! Other natural dyes that work on playdough (so I'm not sure if they'd be strong enough for soap) are red cabbage (turns blue, turn it back to fuschia pink with lemon juice), beetroot, blueberries, turmeric, etc. These tasty combos found via Just a thought, but maybe you knew all this already ; )

  5. Melissa – Thanks so much 🙂

    Dani – So many fun things to make, so little time! My pinterest is going mad with all the project ideas I'm picking up myself 😉

  6. Pat – You think you know what's in a product by the label and in so many cases the true processes and ingredients aren't listed! Take fragrance oils for instance – their ingredients are actually patented and secret so can't actually be displayed. Or processed chicken that's washed in ammonia to kill off bacteria – I'll bet no one's ever seen that on a label before either. The world of processed goods is a scary one!

  7. Caro – Thanks for the tips and am really interested in how you make homemade play-doh! That sounds fun 🙂 I know about most of your natural colours already but most of them are unfortunately unsuitable for soap making. Due to the high heat and the chemical process between oils and lye, most natural colours morph. For example, beetroot and blueberry juice turn a horrible brown. Tumeric can be used but if you use too much of it your soap (any your skin) smells like it as well! lol I've never tried red cabbage but have heard it can also give a nice blue colour to soap. Thanks for the reminder of that!

  8. I really admire the fact that you go to all this trouble making soap. Have you ever seen the film 'Fight Club' he makes his own soap using the fat taken out from liposuction operations. Not something you indulge in I hope.

  9. Elaine – LOL!! Wouldn't that be handy after Christmas? Alas, my soaps are all vegetarian 😉

  10. Christine says:

    Thank you for this post Tanya it was very interesting. Looking at the photo of Woad, I'm almost certain there is lots of that growing wild a hundred yards from my gate. I shall have to investigate.
    Thanks again

  11. Sue – Thank you 🙂

    Christine – Woad is a wild plant in most of Britain so definitely harvest it if you can find it! It doesn't seem to grow on the IoM though so I sadly would have to grow it like a garden plant. Lucky you!

  12. Jo says:

    It's amazing how plants give a different dye colour to what you would think. Your soaps are so pretty, I love the moulds you've used.

  13. Mr. H. says:

    I'm glad you brought these to my attention, both plants are hardy enough to grow in my climate. The extracted colors are fascinating.

    We have a plant that grows around here called Oregon Grape whose stems and roots yield a yellow dye, we once used it to dye curtains, not sure if it would work in a soap mixture.

    Lovely soaps in the above picture. Have you ever made your own lye using wood ash?

  14. Jo – Thank you 🙂 I chose the mould since the triple-spiral is the ancient symbol of the island I live on. It's kind of evolved into a medieval three legged thing now but originally was a type of trinity meaning sea, sky and earth.

  15. Mr H. – I had to look that one up but know exactly which plant you mean – It's mainly referred to here as Mahonia and is used in herbal medicine. It's effective in the treatment of skin conditions such as acne and even psoriasis…very cool that it also can be used as a dye!

    I know the method of making lye from wood ash but it results in a slightly different lye called Potassium Hydroxide opposed to Sodium Hydroxide which I use. I like to make solid soap bars and the lye you get from wood ash is only good for making liquid or slushy textured soaps. Would be an interesting exercise to try though!

  16. Leigh says:

    This is absolutely brilliant. Being a handspinner, I've dyed with these and other natural dyes numerous times, but always on fiber. I used to make soap (eons ago) and never dreamed of coloring them with natural dyes! As I said, absolutely brilliant.

  17. Hi Leigh – Thanks so much 🙂 There are a few people out there who colour their soaps with natural dyes, though extracts of alkanet and madder seem to be a bit more popular (and easier) than using woad. If you ever try your hand at soap-making again let me know how you get on! In chatting with the folks at it seems that the (woad and madder) dyes they sell for fibre colouring aren't safe to use in cosmetics. So maybe have a look around for pure plant extracts if you decide on some experiments.

  18. Pam says:

    Have you ever tried mixing woad and madder to form purple?

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