Unwashed material
“Unwashed” is commonly used to describe material that has not gone through a washing step intended to reduce soluble salts. It is not automatically unsuitable. The question is whether its chemical condition fits the downstream use, irrigation water, fertilizer programme, and buyer acceptance criteria. Ask for a representative test result and the method used to obtain it.
Washed material
“Washed” indicates that washing is part of the process, generally in response to a soluble-salts requirement. A serious RFQ should say what is to be measured after processing, how the sample is prepared, and what acceptance range applies. The claim is only useful when it is linked to the actual lot, product grade, and test protocol.
Also clarify whether the material will be used directly or blended. A result acceptable for a blended potting mix may not be the right requirement for a dedicated hydroponic crop programme.
Buffered material
Buffering is discussed in commercial substrate systems where buyers want to manage cation behaviour before use. It should be defined by the buyer’s technical requirement, not treated as a universal upgrade. Confirm the intended application, process expectation, laboratory checks, and any required documentation before pricing.
Questions that avoid specification gaps
- What crop, blend, or end market will use the material?
- Do you require pith, chips, fibre, or a specified particle blend?
- Which EC and pH method, unit, and acceptance range will be used?
- What moisture, compression, packaging, and pallet requirements apply?
- Does your receiving team need a sample, batch reference, or laboratory report?
Use one written brief
Put the processing description, physical grade, chemical requirements, test method, packing, quantity, and destination into the same written enquiry. This makes supplier comparison more honest and helps the final shipment match the approved discussion.
Discuss processing requirements