Growing media standards: what four EN measurements tell you
This article is in English.
A growing medium can look right in the bag and still raise questions when you put its figures beside another specification. Was the pH measured in water? Does a conductivity figure describe the peat before fertiliser is added? Is the stated volume the size of the bag or a measured quantity?
Four EN standards help make those conversations more precise. EN 13037 concerns pH, EN 13038 electrical conductivity, EN 13040 moisture and EN 12580 packaged volume. Each answers a different question, so it is worth reading them together rather than treating any one figure as a complete description of a growing medium.
EN 13037 measures pH, but the test detail matters
EN 13037 is the standard behind published pH measurements for growing media. pH tells you how acidic or alkaline a material is. For a grower, the first check is whether the stated pH suits the crop and the way the medium will be managed.
SOLVIKA's unlimed Sphagnum peat moss has a published pH of 3.5 to 4.5 when measured in water. That acidity can be useful as a starting point for blueberries and other acid-loving crops, but it is not the same specification as a pH-adjusted medium intended for other crops. SOLVIKA's pH-adjusted peat moss is limed to pH 5.5 to 6.5 and contains a wetting agent but no fertiliser.
Check the measurement notation before comparing two pH figures. For example, the published grade figures for SOLVIKA's white peat include both pH in water and pH in CaCl₂, with different stated ranges. A number without its measurement context can make two materials appear more similar, or more different, than the specifications actually show.
A published pH is a starting point for selection, not a prediction of the pH around roots throughout a crop. Irrigation water, fertiliser and growing practice can all influence what happens after filling or planting. If your crop has a narrow pH target, specify the measurement you need and monitor the medium under your own conditions.
EN 13038 measures electrical conductivity
Electrical conductivity, usually shortened to EC, is an indication of soluble salts in the measured material. EN 13038 is the standard used for SOLVIKA's published EC figures. It helps a grower distinguish a low-salt raw ingredient from a medium that contains a starter fertiliser charge, provided the figures being compared refer to the same kind of product.
SOLVIKA publishes EC in water below 0.3 mS/cm for its peat moss. That figure belongs to the unlimed peat moss specification. It should not be carried over to a ready-to-use seeding or potting substrate, because those ranges contain starter fertiliser.
EC cannot tell you which nutrients are present or whether a medium has the right feeding programme for a particular crop. It is also worth checking whether a supplier's figure describes raw peat, a pH-adjusted base or a fertilised mix. Those distinctions matter when a nursery is replacing one input with another while keeping its existing feed regime.
- For your own recipe. Start by identifying whether you need low-salt peat or a pH-adjusted base without fertiliser, then assess your planned nutrient additions separately.
- For a ready-to-use mix. Read the EC figure alongside the declared starter fertiliser and your crop requirements. Do not use EC alone as a substitute for a fertiliser specification.
EN 13040 measures moisture in the material
EN 13040 is the standard used for SOLVIKA's published moisture figure. Its peat moss specification states moisture of 35 to 55%. This describes moisture in the supplied material, not the water-holding capacity of a filled pot or the irrigation level a crop will need.
That distinction is useful in practical handling. A peat delivery is not expected to behave exactly like a pot after it has been filled, watered and allowed to drain. When trialling a new grade, check how it takes up water under your filling and wetting procedure rather than assuming the published moisture figure answers that question.
Moisture also matters when interpreting weight. A load's weight cannot be converted into a reliable volume using a single assumed value if the material and its moisture differ. White and dark peat also have different published bulk-weight ranges, so specify the peat type and packaging when discussing a shipment.
EN 12580 measures packaged volume
EN 12580 is the standard SOLVIKA uses for packaged-volume measurement. Volume is the quantity to check when you are ordering bags or big bales for a filling line, resale or further blending. It is a different figure from bulk weight and should not be treated as a simple weight conversion.
Read a volume alongside the exact product and pack format. SOLVIKA offers different sizes across its peat moss and substrate ranges, and availability varies by product. A specification for one bag size does not establish which sizes can be supplied for every grade.
For production planning, estimate the volume you need from your own tray, pot or mix recipe, then confirm the proposed pack size and order quantity. Filling practice and the way a medium is handled affect how far a delivered volume goes in a nursery. A small-scale fill test is more useful than assuming every screened grade will fill identically.
Typical values are for selection, not a batch guarantee
Published figures help narrow a choice of growing medium. SOLVIKA states that figures on its product pages are typical values for the grade rather than guarantees for a single batch. This is an important distinction if your purchasing specification sets a strict acceptance limit.
Start with the product's intended use, peat type, screening and additives. Then compare pH with pH, EC with EC, moisture with moisture and packaged volume with packaged volume. Keep the measurement notation and product type attached to each number, especially when comparing unlimed peat with a fertilised substrate.
If you need evidence for a particular consignment, ask for a batch analysis rather than treating a typical grade sheet as a batch result. Say which measurements you require, the limits you work to and whether your specification names a particular measurement method. Ask early, so the requirement can be discussed against the product and order you intend to place.
A useful request also describes what you will do with the material. Tell the supplier whether it is for plug trays, potting, blueberry planting or blending into another medium, and identify any existing product you are trying to replace. That context makes a technical conversation more productive than sending a target pH or EC number on its own.
The four standards answer four separate questions. Together, they make a specification easier to read and a trial easier to plan, but they do not replace a crop test in your own system. Use the published figures to choose a candidate grade, then request batch-specific information where your quality process needs it.
Frequently asked questions
What does EN 13037 pH growing media testing tell me?
It provides the basis for a pH measurement, which tells you how acidic or alkaline the material is. Check the measurement notation as well as the number, since pH stated in water and pH stated in CaCl₂ should not be compared without that context.
Is a low EC figure the same as having no fertiliser?
No. EC indicates soluble salts in the measured material, but it does not identify the nutrients present. SOLVIKA's published EC in water below 0.3 mS/cm applies to its peat moss, not automatically to its fertilised seeding and potting mixes.
Does EN 13040 moisture tell me how much water a pot will hold?
No. The published moisture figure describes moisture in the supplied material. Water uptake and behaviour in a filled pot should be checked under your own filling, wetting and irrigation conditions.
Can I use a product-page figure to approve a particular batch?
SOLVIKA's product-page figures are typical values for a grade, not guarantees for an individual batch. If your approval process requires consignment-specific results, ask for a batch analysis and state the measurements and limits you need.
Send us your crop or blending application, target specification, required measurements, packaging, volume and destination through our contact form. If you need a delivered quotation, include your preferred delivery term.
