01 · Direct answer.
Landscaping uses the Natural grade: the material sits on the surface or in topsoil mixes and EC is not critical. Nurseries choose the grade by crop: Natural for coffee, clonal eucalyptus, citrus and leafy vegetables; Washed for forestry seedlings, potted ornamentals and soilless vegetables; Buffered for seed sowing, flowers, orchids, strawberry and tomato. Substrate manufacturers buy Natural or Washed with an EC ceiling fixed in the contract and receive EC, pH, moisture and density for every lot.[1][5]
| Application | EC tolerance | Grade | Usual format |
|---|---|---|---|
| Landscaping, mulch, bed cover, topsoil | High | Natural (any grade works) | 100 L bag; coir fiber for mulch and slopes |
| Nursery: coffee, clonal eucalyptus, citrus, leafy crops | Medium | Natural, limit in contract | 100 L bag |
| Nursery: forestry seedlings, potted ornamentals, soilless | Medium-low | Washed | 100 L bag |
| Seed sowing, flowers, orchids, strawberry, tomato | Low | Buffered | 100 L bag; blocks under contract |
| Substrate manufacturers and blenders | Contract ceiling | Natural or Washed | 100 L bag, bulk or pressed under contract |
Matrix as published on Carve's Coir Pith and Applications pages. EC is measured on each lot; the grade is defined in the contract.
02 · Landscaping and bed cover.
- Use: bed cover, planter base, topsoil component, mulch in green areas. It is the application with the highest tolerance to EC variation.[1]
- Why Natural is enough: the material is not in prolonged contact with roots in a closed, wet medium; rain and surface irrigation lower EC over time.[1]
- Water holding: dry-husk coir pith holds 8 to 10 times its dry weight in water and has a total porosity above 94 %, which reduces watering frequency in beds and large pots.[2]
- Coir fiber is used as loose mulch, slope protection and moisture retention; see Coir fiber uses.
- Volume: one kilogram of fine-grade pith gives about 15 liters after hydration.[3] Loose, bulk density is about 90 to 95 kg/m³ at 15-20 % moisture.[2] Detail in Coir pith liters per kg.
03 · Nurseries for forestry, fruit and ornamental seedlings.
Coir pith is used as a substrate for forestry, fruit and ornamental seedlings because it combines water holding, aeration and physical stability during early rooting.[1] Most Brazilian nurseries run at medium EC with controlled fertigation, which allows the Natural grade as long as the lot is within the irrigation protocol's limit.[1]
- Fine grade for germination: "the fine grade is an excellent alternative for germination", and it can be mixed with vermiculite, composts and peat.[4]
- Coir to coir: when the seedling goes on to production in coir substrate, the recommendation is to keep the same material in both phases, rather than moving from peat to coir at transplanting.[4]
- Finer means more water: a finer substrate holds more water and suits early phases; a coarser substrate drains and aerates more and suits production.[4]
- Particles below 0.5 mm are undesirable because they clog aeration pores; Carve's coir pith is screened at ~4.1 mm.[3]
- Grade by crop: Natural (EC 0.8 to 1.5 mS/cm) for coffee, clonal eucalyptus, citrus and leafy crops; Washed for potted ornamentals, forestry seedlings and soilless crops; Buffered for seed sowing and sensitive crops.[5] The difference between grades is in Washed vs unwashed coir pith.
04 · Substrate manufacturers and blenders.
- What the blender buys: coir pith and coir fiber as industrial inputs, with technical documentation per lot, to formulate its own substrate.[1]
- What comes with each delivery: EC, pH, moisture and bulk density of the lot, the data needed to keep its own recipe consistent.[1]
- EC ceiling in the contract: an out-of-standard lot does not ship.[1] Inside Brazil the invoice is issued as a sale of an agricultural input; export shipments carry the lot report in the document set.
- A ratio is not a specification: "there is no standardisation in the industry" for labels such as 70-30 or 50-50; what matters is the retention curve of the final mix.[4]
- Compatibility: coir "coexists very well with practically any conventional substrate", in mixes with compost, vermiculite, perlite and peat.[4]
- Logistics: the load is limited by volume, not weight; bags, bulk and pressed formats are in Coir pith lead time and freight and Coir pith per truck.
05 · What to ask for on the lot report.
| Parameter | Method | Reference |
|---|---|---|
| Electrical conductivity | 1:5 v/v extract | Raw dry husk 0.4-6.0 mS/cm; Natural 0.8-1.5; measured per lot |
| pH | 1:5 extract | Reported per lot; raw dry husk 4.9-6.0 in the literature |
| Moisture | Weighing before and after drying | Maximum 18 % (wet basis) |
| Bulk density | Mass / volume, loose | ~90-95 kg/m³ at 15-20 % moisture |
| Particle size | Inspection against ~4.1 mm screen | Retained fiber limited; pith below 0.5 mm undesirable |
Methods and limits as on the Quality page; the report content is described in Coir pith lot report (COA) and EC in Coir pith EC by crop. Company data on Company facts.
06 · Frequently asked questions.
Do I need washed coir pith for landscaping?
No. Landscaping, mulch and bed cover are the application with the highest tolerance to variation in electrical conductivity, and the Natural grade is suitable. The material sits on the soil surface or goes into topsoil mixes, and rain and surface irrigation lower EC over time.
Which coir pith grade should a seedling nursery use?
It depends on the crop. Coffee, clonal eucalyptus, citrus and leafy vegetables accept the Natural grade, with EC 0.8 to 1.5 mS/cm and a limit fixed in the contract. Forestry seedlings, potted ornamentals and soilless vegetables call for Washed. Seed sowing, flowers, orchids, strawberry and tomato call for Buffered. In every case EC is measured per lot.
How many liters of substrate does one kilogram of coir pith make?
For fine grade, about 15 liters per kilogram after hydration, according to a Colombian industry specialist; Carve's export block specification guarantees a minimum of 13 L/kg. Loose, coir pith has a bulk density of about 90 to 95 kg/m³ at 15-20 % moisture.
What does a substrate manufacturer receive with each delivery?
EC (1:5 extract), pH, moisture and bulk density of the lot, measured on the bench, with a QR on the bag that opens the test record. The EC ceiling is fixed in the contract and an out-of-standard lot does not ship. Export shipments carry the lot report in the document set.
Can coir pith be mixed with other materials?
Yes. Coir pith is combined with vermiculite, compost, pine bark, coir fiber and peat in common formulations. What defines the result is the retention curve of the final mix, not the nominal ratio. For a nursery crop that goes on to production in coir, a Mexican specialist recommends keeping the same material in both phases.
07 · Sources.
- Carve public pages Applications and Coir Pith: application matrix by EC tolerance, per-lot documentation for blenders, contractual ceiling.
- EMBRAPA Tabuleiros Costeiros, Comunicado Técnico 226: total porosity >94 %, water holding 8-10× dry weight, raw EC 0.4-6.0 mS/cm, pH 4.9-6.0, density <0.09 g/cm³; Manickam & Suresh (2011), IJEST 3(4): density regression by moisture and particle size.
- Ing. Adalberto Romero webinar (Science Fetti / El Semillero, Colombia, 2025): expansion 15 L/kg for fine grade; particles <0.5 mm undesirable.
- Lic. David Cadena webinar (Mexico, hosted by Riego Rotoplas, 2026): fine grade for germination; coir-to-coir recommendation; fine substrate for early phases and coarse for production; no standardisation of ratio labels; compatibility of coir with compost, vermiculite, perlite and peat.
- Carve public specification: Natural (EC 0.8-1.5 mS/cm), Washed and Buffered grades by crop; export blocks with a minimum expansion of 13 L/kg (Import Coir from Brazil).