The short answer: coco coir roots cuttings as well as peat does, provided you open it up with perlite so the base of the cutting gets air. A 50:50 coir and perlite mix suits most softwood and semi-hardwood cuttings. Keep the medium at about 21 to 24 °C (70 to 75 °F) with bottom heat, hold humidity high with mist or a closed case, and match the rooting hormone strength to the cutting type.
Key facts
- Where coir and peat have been compared side by side in cutting mixes, rooting was the same or very close. Coir dust mixes matched peat-based ones, and plain coir fibre, or coir with perlite at 1:2, rooted spruce cuttings well.
- Most cuttings root best with the medium at 21 to 24 °C. Bottom heat matters because the medium can run 5 to 10 °C cooler than the air, and mist cools it further.
- Run mist in daylight only. Mist at night keeps the medium too wet and invites rot.
- IBA labels run from 150 to 500 ppm for herbaceous cuttings, 500 to 1,000 ppm for softwood, and 5,000 to 20,000 ppm for difficult-to-root material. Species vary a lot.
- Softwood cuttings of easy plants often root in two to four weeks.
Why coir works for cuttings
A cutting has no roots, so it can't take up much water. It needs a medium that stays damp around the stem base, holds no standing water, and lets oxygen reach the cut surface where roots form. It also needs to be clean and low in salts, because the cut end takes up whatever is in the water.
Washed coir pith ticks most of those boxes. It holds water evenly, rewets after drying without sitting dry in patches, and has a pH of roughly 5.6 to 6.9, which suits most shrubs, perennials, herbs and fruit.
Its weak point is air. Fine pith on its own holds too much water for a cutting stuck under mist. That's why every cutting mix that uses coir pairs it with perlite, sand or coarse fibre. If you want the numbers on how each amendment shifts air and water, see our coir, perlite and vermiculite mixes guide.
Mixes by cutting type
| Cutting type | Coir : perlite (by volume) | Notes |
|---|---|---|
| Herbaceous and soft herbs (mint, basil, pelargonium, salvia) | 60 : 40 | Root fast. Too much mist rots them, so lean drier |
| Softwood shrubs and perennials (fuchsia, hydrangea, lavender) | 50 : 50 | The standard mix under mist |
| Semi-hardwood (rosemary, box, camellia, citrus, blueberry) | 50 : 50 or 40 : 60 | Longer in the bench, so keep it open |
| Hardwood, outdoors or in a cold frame (currant, fig, willow, grape) | 50 : 50, or coir with coarse sand | Less mist, longer period, sand adds weight |
| Leaf and leaf-petiole cuttings (begonia, African violet, succulents) | 40 : 60 or perlite-heavy | Rot risk is high |
Some growers go further and use 75% perlite to 25% coir for almost everything. It roots well but needs more frequent watering outside mist. An equal mix of coir, vermiculite and perlite is another good option where you want a little more water held, for example in a closed case without mist.
Use a fine, washed coir grade with long fibres sieved out for small cells. Long fibre bridges in a plug cell and leaves a gap under the cutting. For trays of individual plugs, a netted or bonded coir plug is another route, covered in our article on coir discs and propagation plugs.
Step by step
- Pre-wet the mix. Hydrate the coir, blend in the perlite, and squeeze a handful. A few drops should come out, no stream. Fill trays or cells and firm lightly.
- Take cuttings in the morning when the stock plant is full of water. Most stem cuttings are 5 to 15 cm (2 to 6 in) long, cut just below a node.
- Strip the lower leaves and reduce large leaves by half so they lose less water. Leave two to four leaves on soft cuttings.
- Wound woody cuttings with a short, shallow slice through the bark at the base. Wounding improves rooting on many semi-hardwood and hardwood cuttings.
- Apply rooting hormone. Tip a little powder or solution into a separate dish so you don't contaminate the stock. Dip, tap off the excess.
- Dibble a hole and insert the cutting so a third to a half of it is in the mix. Pushing straight into the mix scrapes the hormone off.
- Water in once and put the tray into mist, a propagator, or under a clear cover.
- Check after two to three weeks by tugging gently. Resistance means roots. Pot on once roots show at the cell sides.
Mist, humidity and the wet-base problem
The leaves of a cutting keep losing water while it has no roots to replace it. Mist or a closed case slows that loss. Coir makes the balance easier than peat in one way and harder in another.
The easy part: coir doesn't dry into a water-repellent crust, so if a misting line clogs for a day you haven't ruined the batch.
The hard part: coir holds more water than perlite does, so a tray of coir under a heavy mist schedule gets wet at the base faster. Signs are blackened stem bases, a sour smell and fungus gnats. The fixes:
- Mist in daylight only. Night mist keeps the medium too wet.
- Mist to keep leaves damp, not to water the tray. Short bursts of a few seconds every several minutes on sunny days, less in cloud. Cut back as soon as roots appear.
- Use a free-draining bench or mesh trays so water never stands under the cells.
- Raise the perlite share if trays stay heavy.
For gnats and the algae that grows on wet coir surfaces, see our article on mould, algae and fungus gnats in coco coir.
Bottom heat
Roots form faster in warm media. For most cuttings the target is 21 to 24 °C (70 to 75 °F) in the medium, with air a few degrees cooler so the top doesn't race ahead of the roots. Garden propagators commonly give 18 to 24 °C of bottom heat, which covers most plants. Some crops want more. Poinsettia, for example, roots fastest with the medium at 26 to 28 °C.
Three practical points:
- Measure the medium, not the air. Push a probe thermometer into a cell. The medium can run 5 to 10 °C below air temperature in a cool greenhouse, and mist cools it further.
- Coir's high water content takes a while to warm. Turn the heat mat on a day before you stick, so the tray is at temperature when cuttings go in.
- Turn the heat down once rooted. Continued warmth pushes soft growth and uses up the cutting's reserves.
Bottom heat has the biggest effect in winter and early spring, and on hardwood and semi-hardwood cuttings. Softwood cuttings in summer often root without it.
Rooting hormone strength
IBA (indole-3-butyric acid) is the auxin in most rooting powders and gels. Strengths are given in ppm or as a percentage, where 0.1% equals 1,000 ppm.
| Cutting type | IBA range on product labels and in propagation work | Example plants |
|---|---|---|
| Herbaceous | 150–500 ppm, or none | Mint, coleus, pelargonium |
| Softwood | 500–3,000 ppm | Fuchsia, salvia, hydrangea |
| Semi-hardwood | 1,000–3,000 ppm, up to 6,000 for slower species | Camellia, citrus, olive, rosemary |
| Hardwood and difficult-to-root | 3,000–9,000 ppm, up to 20,000 ppm on some labels | Fig, holly, viburnum, some conifers |
Published figures overlap and the best rate is species-specific. Viburnum hardwood cuttings rooted 90 to 100% with a 6,000 to 9,000 ppm quick dip. Olive semi-hardwood cuttings did best at 3,000 ppm. Some shrubs peak at 1,000 to 2,000 ppm and do worse above it. Too much IBA burns the base and can stop rooting altogether, so start at the low end for soft material.
Coir doesn't interact with IBA in any special way. The things that do matter are a clean, low-salt medium, which keeps the cut end healthy, and not knocking the hormone off when you stick.
Feeding rooted cuttings
Cuttings don't need fertiliser until they root. Fertiliser in the propagation mix raises EC around a cut stem and can slow rooting. Once roots show, start a dilute complete feed with calcium and magnesium, and pot on into a richer mix within a couple of weeks. Coir carries almost no nitrogen, so rooted cuttings left in pure coir and perlite turn pale quickly.
Fruit and nursery cuttings at scale
Nurseries rooting thousands of cuttings use the same principles with more control: fixed-volume coir plugs or filled trays, mist controlled by leaf wetness or light, and heated benches. Our nurseries page covers coir for young plant production more broadly.
Supply
CVM Fiber and Industries makes washed coco peat in Kanyakumari, Tamil Nadu, India, washed with water to reduce EC and supplied unbuffered, with no calcium nitrate or other chemicals. It comes in 5 kg blocks, 650 g briquettes and custom blends. If you're setting up a propagation mix, contact us to talk through grades.
FAQ
Can cuttings root in 100% coco coir?
Many will, especially easy herbs and soft perennials, but pure fine coir holds too much water under mist and slow cuttings can rot. Add perlite at 40 to 50% for most cuttings. Coir fibre or a coarse coir grade on its own is more open and works better than fine pith.
Is coco coir better than peat for rooting cuttings?
Rooting results are usually the same or very close. Coir rewets more easily and has a pH that needs no correction, which makes it simpler to manage. Peat holds slightly more air at the same particle size. Either needs perlite or sand for good aeration.
What is the best coco coir to perlite ratio for cuttings?
A 50:50 mix by volume is the standard for softwood and semi-hardwood cuttings. Use around 60:40 for fast herbaceous cuttings and 40:60 for leaf cuttings, succulents or slow-rooting woody plants that sit in the bench for months.
What temperature should the medium be for rooting cuttings?
About 21 to 24 °C (70 to 75 °F) for most plants, with the air slightly cooler. Measure inside the medium, because mist and cool air keep it below air temperature. A few crops such as poinsettia prefer 26 to 28 °C.
Do I need rooting hormone with coco coir?
Easy plants like mint, willow and fuchsia root without it. Semi-hardwood and hardwood cuttings usually root faster and more evenly with IBA. Coir doesn't change how the hormone works, so use the strength suited to the cutting type and species.
Why are my cuttings rotting in coco coir?
The medium is too wet or too cold. Raise the perlite share, mist only in daylight and only enough to keep leaves damp, stand trays on a draining bench, and add bottom heat. Remove dead cuttings quickly so rot doesn't spread.
How long do cuttings take to root in coir?
Softwood cuttings of easy plants often root in two to four weeks. Semi-hardwood cuttings take longer, and hardwood cuttings can take months. Warm media and good humidity shorten the time.
Should coir for cuttings be buffered?
Not necessarily. Unrooted cuttings take up very little nutrient, so washed, low-EC coir is what matters. Once roots form, a complete feed with calcium and magnesium covers what buffering would otherwise address.