The short answer: coconut husk chips are cut pieces of coconut husk, usually 5–25 mm across, used as a coarse, airy potting medium for orchids, anthuriums and other epiphytes, and as a structure component in coco peat blends and hydroponic slabs. They hold more water than pine bark and give up roots more easily at repotting, but they arrive with salts that have to be soaked out, and under constant moisture and fertiliser they can break down faster than many sellers suggest. Rinse them in several changes of water, check the EC of the last rinse, and match the chip size to the pot size and the plant.
Key facts
- Three products come from the husk: coir pith, coir crush or chips, and coir fibre, made by "different ways of cutting, sieving and grading" (Klasmann-Deilmann technical note).
- Adding chips to a mix can raise its air content "by 10 to 40%" depending on quantity, size and shape (Klasmann-Deilmann).
- A 70% coco peat / 30% coco chip factory mix measured 40.4% air-filled porosity and the lowest water retention of four blends tested (University of Peradeniya, 2025).
- Coconut husk "holds water longer than pine bark"; the author saw no appreciable deterioration after 18 months (B. Milligan, Orchid Society of Victoria).
- In another grower's trials, chips kept constantly moist and fertilised "degraded within a year" (C. Hackney, St. Augustine Orchid Society, 2003).
What coconut husk chips are, and how they differ from pith and fibre
The coconut husk (the fibrous mesocarp between the outer skin and the hard shell) is made of long fibres held together by a spongy, cork-like pith. Coir processors separate these into three raw materials. Klasmann-Deilmann's technical note "Coir Physically" lists them as coir pith, coir crush or chips, and coir fibre, each produced by cutting, sieving and grading the husk in different ways.
| Product | What it is | Role in a growing medium |
|---|---|---|
| Coir pith (coco peat) | The fine, spongy material left when fibre is removed; usually sieved, for example through a ¼ inch screen | Holds water; Premier Tech reports pith can hold "up to nine times its own weight in water" |
| Coir chips (husk chips, coco chips, coir crush) | Whole husk cut into cubes or irregular pieces, fibre and pith still bonded together | Adds air space and structure; makes a mix drier and faster-draining |
| Coir fibre | Long fibres, sometimes cut short for substrates | Mainly used in mats, brooms and geotextiles; in mixes it improves water and air distribution and is "always" mixed with other constituents (Klasmann-Deilmann) |
The key difference is that a chip keeps the husk's original structure. Because fibre and pith remain bonded, a chip behaves like a small sponge with large air gaps between neighbouring chips. Pith, by contrast, is loose and fine, so it packs closely and holds water in small pores. This is why Klasmann-Deilmann says plainly that "the use of coir crush makes a mixture drier."
Common size grades
There is no published Indian or Sri Lankan standard that defines husk chip sizes; the grades below are the bands most often seen in supplier listings and in research, and the labels differ from one supplier to the next. Ask for the millimetre range rather than a name.
| Typical band | What it is called | Where it is used |
|---|---|---|
| Under 5–6 mm | fine chips, "crush", mulching grade | Blended into pith for grow bags and slabs; small-pot mixes |
| 6–12 mm | small or medium chips | Phalaenopsis and small-pot orchids, anthurium pots, 30–50% blends with pith |
| 12–18 mm | medium or coarse chips | General orchid mixes, cattleyas, aroids, bark replacement |
| 15–25 mm and larger | large chips | Large epiphytes, vandas, hanging baskets, top dressing |
The Brazilian UNESP study of coconut fibre particle fractions defined "chips" as 15–25 mm, "mixed" as 5–15 mm and "granulated" as under 5 mm, which is a useful reference when comparing supplier grades. Anthura, the Dutch orchid and anthurium breeder, refers to coco chips by numbered fractions and notes that "smaller fractions are easier to desalt than larger ones", which matters when you choose a size (see preparation below).
Properties: air, water and how long chips last
Published figures for pure husk chips are scarce; most research measures coir pith or blends. The numbers below are what reputable sources report, with the material tested stated for each.
| Property | Figure | Material and source |
|---|---|---|
| Air-filled porosity | 13–28% | Coir in general; Hort Innovation Australia, "Coir and its alternatives" (2022) |
| Air-filled porosity | 9.5–12.6% at container capacity | Coir dust (pith) from five sources; Evans, Konduru and Stamps (1996) |
| Air-filled porosity | 40.4% | 70% coco peat + 30% coco chips factory blend; Kavinthini and Vidana Gamage, University of Peradeniya (2025) |
| Air content increase | +10 to 40% | Effect of adding coir crush/chips to a mix; Klasmann-Deilmann |
| Water holding | 750–1100% of dry weight | Coir dust; Evans, Konduru and Stamps (1996) |
| Water retention at 50 cm suction | 0.28 cm³/cm³ (lowest of four blends) | 70/30 peat/chip blend; University of Peradeniya (2025) |
| Bulk density | 0.057–0.064 g/cm³ | Four coir blends including 30% chips; University of Peradeniya (2025) |
| Relative water holding | more than pine bark, less than sphagnum | Pure coco husk in orchid pots; B. Milligan, Orchid Society of Victoria |
Two things stand out. First, chips are an aeration component: in the Peradeniya trial the 30% chip blend had the highest air-filled porosity and the lowest water retention, and it let nitrate and phosphate leach through earliest. The UNESP study points the same way: as particle size dropped from the 15–25 mm chip fraction to the sub-5 mm fraction, the solid fraction fell from roughly half the volume to under a tenth and easily available water rose sharply. Second, pure chips still hold a lot of water compared with bark, because each chip is itself a sponge. Growers who switch orchids from bark to chips almost always water less often.
How long do husk chips last?
Sellers often quote three to five years. Independent reports are less tidy and worth reading side by side:
- Brian Milligan (Orchid Society of Victoria) wrote that coco husk "breaks down more slowly than bark" and that after 18 months he saw "no appreciable deterioration", while warning that his results covered only 12–18 months and that many mixes perform well at first and turn sour later.
- Dr Courtney Hackney (St. Augustine Orchid Society, 2003), after repotting several hundred orchids, found that mini-cattleyas in 100% chips kept moist needed repotting "after a year because the medium was almost totally degraded", and that in a 25% chip / 25% sponge rock / 50% peat-based Phalaenopsis mix the chips also "degraded within a year." His conclusion: "under constant moisture and fertilizer they degrade too quickly." Yet the same chips mixed into Paphiopedilum mixes extended the life of those mixes by as much as a year.
- The American Orchid Society (Ned Nash) notes that coconut husk is mainly lignin rather than cellulose, so it is probably not attacked by the wood-rot organisms that make high-nitrogen feeds necessary for bark, and recommends a balanced fertiliser instead.
- Klasmann-Deilmann, on the other hand, points out that young coir has a high proportion of cellulose relative to lignin and is "physically unstable"; during cultivation it "becomes finer and wetter and the air content decreases." The company ages its coir before sale to reduce the cellulose. Premier Tech makes the opposite general point, that coir's high lignin-to-cellulose ratio resists breakdown.
Reading these together: stability depends on the age and source of the husk and on how wet and how heavily fed the pot is kept. Expect one to two years in a wet, fertigated orchid pot, longer in a drier regime. Orchidweb's repotting guide gives bark about two years and sphagnum about one, so chips sit in the same bracket rather than far beyond it. Repot when the chips feel soft and the mix stays wet much longer than it used to, not on a fixed calendar.
Why orchid and anthurium growers use husk chips
Orchids. Chips give a chunky, open mix that roots can grip, with more moisture between waterings than bark. Milligan reported his best results with cymbidiums (healthy roots, even on back-bulbs), good results with lycastes, coelogynes and several dendrobiums, and an Angraecum magdalenae that flowered for the first time after a year in the mix. He also noted that chips release from roots more easily than bark at repotting and are gentler on the hands. Among commercial Phalaenopsis growers in Europe, Anthura describes a typical substrate as pine bark plus "20% or 30% coco chips", with coconut making up 10–50% of the volume in general and 100% coconut "feasible if salt levels are controlled."
The honest caveat is that not every trial favours chips. In a controlled study of eight media for Phalaenopsis 'Pauline' (Amberger-Ochsenbauer, Acta Horticulturae 878, 2010), plants in mixes containing coconut husk chips stayed smaller and produced fewer spikes and flowers than the standard 70% pine bark / 30% coarse peat mix, while wood-fibre and sphagnum mixes matched or beat the standard. Milligan likewise relayed other growers' reports that paphiopedilums and phragmipediums did worse in coco husk than in bark, and that weaker masdevallias struggled. Salt-sensitive and fine-rooted genera are the ones to trial cautiously.
Anthuriums. Pot anthuriums and aroids like the moisture-plus-air balance of chips, and Anthura notes that coconut substrates are used for cut anthurium in India and Thailand (in Thailand alongside charcoal). Anthura's cut-flower advice is a useful counterweight: it flags "high salt content (NaCl) and poor buffering" in coconut products, requires at least three rinses until the EC is no higher than 0.5 mS/cm, and notes that a cut-anthurium bed must stay stable for six to seven years, which is why European cut-flower growers prefer inorganic media. For pot plants repotted every year or two, that long-term stability matters far less.
Coco chips vs pine bark
| Coconut husk chips | Pine bark | |
|---|---|---|
| Water holding | Higher; stays moist longer (Milligan) | Low; Anthura says bark's moisture retention is "very low" so pure bark needs sphagnum, coconut or perlite added |
| Air space | High between chips; each chip also absorbs water | High; dries fast |
| Breakdown | Mainly lignin; one to two years in wet, fed pots, longer if drier | About two years (Orchidweb); flat, flaky bark breaks down faster than rounded bark (Anthura) |
| Nitrogen demand | Balanced feed is adequate (American Orchid Society) | High-nitrogen feed often used because decomposing bark ties up nitrogen |
| Salts on arrival | Sodium, potassium and chloride; must be rinsed | Low; no rinsing needed |
| pH | Near neutral to slightly acidic; Premier Tech gives pith at about 6.0 | Acidic |
| Handling | Light, releases from roots easily | Heavier, roots cling to it |
| Suitability | Cymbidiums, cattleya alliance, dendrobiums, aroids, anthuriums | Traditional for most epiphytes; preferred by some growers for paphiopedilums and phragmipediums |
Neither is better across the board. If your plants dry out too fast in bark, or you travel and water irregularly, chips help. If you tend to overwater, or you grow salt-sensitive slipper orchids, bark or a bark-heavy blend is the safer start. Many growers mix the two, which is exactly what Anthura's bark-plus-20–30%-chips recipe does. For a wider comparison of coir against peat, see coir vs peat.
Husk chips in hydroponics and as a blend component
In soilless vegetable and berry production, chips are rarely used alone. They are blended into coir pith to open up the structure of grow bags and slabs, so that the slab drains and re-aerates quickly after each irrigation. The ratio sets the air/water balance:
| Pith : chip ratio (by volume) | Character | Reported use |
|---|---|---|
| 100 : 0 | Wettest, highest water retention | Propagation, small pots |
| 80 : 20 | Slightly more open | Supplier guidance of "20–30% chips by volume" to open the structure in large containers |
| 70 : 30 | Open, fast-draining; measured at 40.4% air-filled porosity, lowest water retention and earliest nutrient breakthrough of four blends (University of Peradeniya, 2025) | Common stock blend for grow bags and open-top slabs |
| 50 : 50 | Very open, dries fast | Tropicoir markets a 50/50 chip/pith bag for tomato, cucumber and capsicum |
| 0 : 100 | Coarse, low water retention | Orchids, aroids, top layer to reduce evaporation |
Three practical notes follow from the Peradeniya data. A high-chip blend needs more frequent, smaller irrigations, because it holds less water and lets nutrients pass through sooner. Chip blends suit crops and climates where root-zone oxygen is the limiting factor (long-season tomatoes and cucumbers in warm greenhouses, blueberries in pots). And the study's 80% pith + 20% short fibre mix retained more water and nutrients than the chip blend, so chips and fibre are not interchangeable. Premier Tech uses coir chunks in its peat-based mixes for the same reason: they are "added to give structure and improve air porosity".
CVM supplies coconut husk chips in graded sizes, and pith-and-chip custom blends in the ratios above, for hydroponic and soilless growing. If you are specifying a grow bag or slab, state the pith-to-chip ratio and the chip size band on the specification; the Greenhouse Grower guide to specifying coco substrate lists "pith-to-chip ratio, particle size fractions, fiber content" as the physical grade items a buyer should put in writing.
How to prepare coconut husk chips before potting
Husk chips arrive compressed in bricks or blocks, or loose in bags. Either way they need water before use, and in most cases they need the salts rinsed out. Here is a procedure that reflects what orchid societies and commercial advisers do.
- Expand. Put the brick in a bucket or tub and add water. Tropicoir's grow-bag guidance uses water equal to about 75% of the expanded volume; a brick will take several hours to loosen fully. Break it apart by hand once soft.
- Soak and discard the water. Brian Milligan soaks overnight, sieves off the slurry and repeats the soak twice more; the American Orchid Society describes chips being "soaked in several changes of clean water before use." Anthura's commercial method is at least three rinses, the first two of at least 12 hours each.
- Check the EC of the rinse water. Anthura rinses until the EC is no higher than 0.5 mS/cm. If you have a meter, measure the water after the final soak and compare it with your tap water; if it is still well above the tap reading, soak again. Supplier EC figures for the chips themselves depend on the test method (1:1.5 volume extract, 1:5, saturated media extract or pour-through give different numbers), which is explained in our article on buffered vs unbuffered coco peat.
- Sieve out the fines. Rinsing also washes out dust and small fragments. Milligan discards material that sinks, because it holds too much water, and keeps what floats.
- Optional: add calcium. For salt-sensitive crops, a final soak in a calcium nitrate solution (Anthura uses about 1 g/L for cut anthurium; Tropicoir keeps grow bags in a high-calcium, high-magnesium feed for 48 hours) displaces potassium and sodium held on the coir. Growers of orchids on a balanced feed generally skip this step. Note that calcium-nitrate buffering is not compatible with organic certification.
- Drain and pot. Pot into damp, not dripping, chips. Water in with your normal feed.
Washed coco peat from CVM is rinsed with water to reduce EC and is not treated with calcium nitrate or other chemicals, so any buffering is left to the grower.
Common problems and fixes
Salt damage: brown root tips, leaf-tip burn, slow growth after repotting. The most common complaint, and almost always a rinsing problem. Chips, particularly large ones, give up salt more slowly than fine pith (Anthura). Soak again, longer, with more water changes, and check the EC of the last rinse. If the plant is already in the pot, flush with plain water for several minutes once a month.
Mix stays wet too long. Chips hold more water than bark. Milligan's advice is to group chip-potted plants together and water them on their own schedule, and to keep a plant-free "control pot" of chips that you can upend to see whether the base is still wet. Smaller pots and a coarser chip grade also help.
Breakdown and compaction. Under constant moisture and feeding, chips can collapse within a year (Hackney). Signs are a mix that sinks in the pot, stays wet and smells sour. Repot into fresh chips, and consider a larger grade, a drier watering regime or a blend with inert material (sponge rock, lava rock or perlite).
Drying out. Fully dry chips can be slow to re-wet, though coir re-wets more easily than peat (Premier Tech). Soak the whole pot in a bucket for ten minutes rather than watering from the top.
Nutrient drift. Coir releases potassium and holds calcium and magnesium. Over months this can show as calcium or magnesium deficiency on a feed designed for bark. The American Orchid Society's advice is a balanced formula rather than a high-nitrogen bark feed; include calcium and magnesium in the feed or in the water.
Buying checklist
- Size band in millimetres, not just "medium". Ask whether the chips are screened to remove fines, and what percentage of fines is allowed.
- Washing status and EC, with the test method stated (1:1.5, 1:5, SME or pour-through). An EC without a method cannot be compared across suppliers.
- Sodium and potassium in the extract if you grow salt-sensitive crops; washing lowers loose salts but does not remove everything held on the fibre.
- Age of the husk if the supplier can tell you; aged coir is more stable than young coir (Klasmann-Deilmann).
- Compressed or loose, and the expanded volume per kilogram or per block. Compressed blocks are cheaper to ship but need more work to break apart and rinse.
- Blend ratio if you are buying grow bags or slabs: pith-to-chip percentage by volume, and the chip size used.
- Consistency between batches. Both Milligan and Tropicoir note that coir quality varies with source and processing; ask for a sample from the batch you will receive.
For bulk or container orders of graded husk chips or custom pith-and-chip blends, see the husk chips product page or contact CVM with your size band, blend ratio and EC requirement.
FAQ
Are coconut husk chips good for orchids?
Yes for many genera, with care over rinsing and watering. Cymbidiums, cattleyas, dendrobiums and many aroid-type epiphytes do well in chips or chip-and-bark blends. Phalaenopsis is often grown in bark with 20 to 30 percent chips. Paphiopedilums, phragmipediums and other salt-sensitive, fine-rooted orchids have done worse in some grower reports and one controlled trial, so test a few plants first.
What size coconut husk chips should I use for orchids?
Match the chip to the pot and root size. Chips of about 6 to 12 mm suit small pots and Phalaenopsis; 12 to 18 mm suit general orchid mixes and cattleyas; 15 to 25 mm or larger suit big plants, vandas and baskets. Smaller chips hold more water and are easier to rinse free of salt; larger chips dry faster.
Do I need to soak coconut husk chips before use?
Yes. Chips arrive with sodium, potassium and chloride, and compressed bricks need water to expand. Soak overnight, drain, and repeat at least twice more with fresh water. Commercial growers rinse until the drain water measures no more than about 0.5 mS/cm. Pot the chips damp, not dripping.
Are coco chips better than orchid bark?
Neither is better in every case. Chips hold more water, release roots more easily and do not need a high-nitrogen feed. Bark dries faster, carries no salts and is the safer choice for growers who tend to overwater or who grow salt-sensitive slipper orchids. Many growers blend the two to get the water holding of chips with the fast drainage of bark.
How long do coconut husk chips last in a pot?
It depends on moisture and feeding. One orchid grower saw no deterioration after 18 months in a normal watering regime, while another found chips kept constantly moist and fertilised had broken down within a year. Plan on one to two years, similar to bark, and repot when the chips feel soft and the mix stays wet much longer than it used to.
Can I use coco chips in hydroponics?
Yes, usually blended with coco peat rather than alone. A 70 percent pith and 30 percent chip blend is a common grow-bag and slab recipe; it drains and re-aerates quickly but holds less water and lets nutrients pass through sooner, so irrigate little and often. Pure chips are used mainly as a top layer or for orchids and aroids.
What is the difference between coco chips and coco peat?
Both come from the coconut husk. Coco peat, or coir pith, is the fine spongy material left after the fibre is removed and holds a great deal of water in small pores. Coco chips are pieces of whole husk with fibre and pith still bonded, so they create large air gaps and make a mix drier. Blending the two sets the air-to-water balance of the medium.
Do coconut husk chips need special fertiliser?
A balanced fertiliser is generally recommended rather than the high-nitrogen formula used for bark, because coconut husk is mainly lignin and does not tie up nitrogen the way decomposing bark does. Coir does release potassium and bind calcium and magnesium, so use a feed that supplies both, and flush with plain water periodically to prevent salt build-up.
Sources
- Klasmann-Deilmann GmbH: Technical Note "Coir Physically: Fine tuning with raw materials" (2024)
- Premier Tech Horticulture: "Coir as a component of growing media" training article (2014)
- Kavinthini, A. and Vidana Gamage, D.N., University of Peradeniya: "Characterizing Physiochemical Properties and Nutrient Leaching Behavior of Different Coir-Based Substrate Mixtures", 37th Annual Congress of the PGIA (2025)
- Sanches, L.V.C. et al., UNESP Botucatu: "Ratio solid - air - water of coconut fiber in function to different particle sizes", ASA-CSSA-SSSA Annual Meeting poster (2013)
- Evans, M.R., Konduru, S. and Stamps, R.H.: "Source variation in physical and chemical properties of coconut coir dust", HortScience (1996)
- Hort Innovation Australia: "Coir and its alternatives" booklet, project RB21002 (2022)
- Milligan, B., Orchid Society of Victoria (OSCOV): "Coco Husk as a Potting Medium"
- Hackney, C., St. Augustine Orchid Society: "Coconut in Potting Mixes", Orchid Growing Tips (July 2003)
- Nash, N., American Orchid Society: "Coconut Husk", Orchids Question and Answer
- Amberger-Ochsenbauer, S.: "Evaluation of Growing Media Components for Phalaenopsis", Acta Horticulturae 878 (2010)
- Anthura B.V.: "Substrate Phalaenopsis" and "Substrate Anthurium cut flowers", crop advice pages
- Orchidweb: "Repotting Orchids: Tips and Tricks"
- Garden City Plastics / Tropicoir: "General Guide on Coir Substrates" fact sheet (2020)
- Gnanasekaran, B.: "Washed, Low-EC, or Buffered? How to Specify Coco Substrate for Your Crop", Greenhouse Grower (2026)