Article updated on: August 19, 2026
Few things are as disappointing as spending an afternoon colouring your hair and finding the result barely changed. If that has happened to you, it is worth knowing that plant colour rarely fails at random. It fails for physical reasons, and almost all of them are things you can control.
This guide applies to any henna and indigo based colour, not just ours. The chemistry is the same whoever made the powder.
1. Not enough processing time
- What's happening: plant pigment attaches to the outside of the hair fibre rather than being forced into it, and that takes longer than a chemical reaction driven by peroxide. Cut it short and less pigment has attached.
- What to do: allow around an hour. If your hair has resisted colour before, go to the longer end of whatever range your product specifies. Warmth helps — a shower cap keeps the paste warm and moist, and both speed the process.
2. The paste was the wrong consistency
- What's happening: too thick and the paste won't spread — it sits in clumps and leaves thin patches you won't notice until the colour develops. Too thin and it runs off before it has done anything. Undissolved powder is its own problem: clumped pigment can't make contact with the fibre.
- What to do: mix to the consistency of yogurt — thick enough to stay put, fluid enough to spread. Stir until completely smooth, with no dry pockets. Even coverage matters more than technique; patchy application is one of the most common causes of a patchy result.
3. Something was already on your hair
- What's happening: plant pigment is carried by water, and water is repelled by oil. Conditioner residue, leave-in treatments, styling product, hair oil and heavy sebum all sit between the paste and the fibre. The paste never touches the hair, so nothing attaches.
- What to do: wash with a clarifying, residue-free cleanser on the day. Skip conditioner entirely. If you oil your hair regularly, allow more than one wash to clear it.
4. Silicones
- What's happening: silicones are the same problem as oil, but more persistent. They form a film designed to survive washing, which is exactly what makes them a barrier here.
- What to do: check labels for anything ending in -cone, -conol, -silane or -siloxane. Stop using them a week or two before colouring, and clarify beforehand — one wash rarely removes established build-up.
5. Hard water and minerals
- What's happening: two separate things. Calcium and magnesium deposit on the fibre and behave like residue, blocking contact. Dissolved iron does something different — it reacts with plant polyphenols to form dark complexes, which can pull a result duller, greyer or darker than expected.
- What to do: a chelating or clarifying rinse before colouring removes mineral build-up. If your water is very hard, distilled or filtered water for mixing the paste and for the final rinse makes a measurable difference.
6. Alkaline water and soap-based shampoo
- What's happening: henna's pigment, lawsone, does not hold well on the fibre in alkaline conditions. If your tap water runs alkaline, or you rinse with a true soap shampoo — soap sits around pH 9–10 — colour can lift straight back out during rinsing.
- What to do: rinse with cooler, neutral water and don't extend the wash. Save any soap-based cleanser for later in the week. Note the timing distinction: alkalinity before colouring helps, because it lifts the cuticle. Alkalinity after works against you.
7. Porosity — in either direction
- Low porosity — virgin hair, fine hair and grey hair often have a tight, flat cuticle that resists. These need longer, not more product.
- High porosity — previously bleached, permed or heat-damaged hair takes pigment fast and can look promising on day one, then fade quickly, because a raised cuticle lets colour out as readily as it let it in.
- What to do: for low porosity, wash with a mildly alkaline soap shampoo beforehand to lift the cuticle, and extend the processing time. For high porosity, expect to colour more often and accept a shorter interval — damaged hair cannot be repaired, since the shaft is dead tissue, so the realistic goal is working with it rather than fixing it first.
8. You judged it too early — or dried it too fast
This is the most common reason of all, and it isn't really a failure at all.
Indigo-containing colour is not finished when you rinse it out. Indigo leaves hold a colourless precursor, not a dye: water releases it, it travels onto the fibre while still soluble, and then it oxidizes in place over the following days into the pigment you actually see. A green or muted cast at the first rinse is the normal starting point, not a bad result.
- Don't judge before day three. The tone shifts over 24 to 72 hours. Day one is the one that worries people, and it isn't finished.
- Don't blow-dry it. That reaction needs moisture to continue. Force-dry with hot air and it stops where it stands — and where it stands on day one is a violet-purple partway point. It does not resume later. Air-dry only, no heat, for the first 24 hours.
- Don't shampoo for 72 hours. Partly because alkaline shampoo lifts lawsone back out, and partly because the reaction is still running. Rinse with water only if you need to.
The lingering plant scent is what drives most people to wash early. It fades on its own within a few days — and washing it away takes the colour with it.
Working out which one it was
The result usually tells you where to look.
- Barely any colour at all → something was in the way. Residue, silicone, minerals, or not enough time.
- Patchy, strong in places → application. Paste consistency or coverage.
- Good at first, gone in a fortnight → high porosity, alkaline water, or washing too soon.
- Stalled at purple or green → the hair dried out before oxidation finished. Almost always a hair dryer.
- Greys lighter than the rest → normal. Grey is usually the lowest-porosity hair on your head and often needs a second application.
The short version
Plant colour asks for three things that chemical colour doesn't: a clean fibre, enough time, and moisture afterwards. Nothing is forced open and nothing is stripped out, which is why it does no structural damage — and also why it can't push past a barrier the way peroxide can.
When someone says herbal colour "doesn't work," one of the eight above is usually the reason. None of them are the powder.