Blonde peat is the backbone of most professional growing media: if you produce seedlings, pot on young plants or formulate custom mixes, you have almost certainly worked with it. But what exactly does it do, when should you prefer it over black peat, and which grain size should you choose? Let’s take it step by step.
What is blonde peat?
Blonde peat is lightly decomposed sphagnum peat: the plant material still keeps its fibrous structure, recognisable by the light colour that gives it its name. On the Von Post scale — the scale used to grade peat decomposition — it sits in the early grades (H2–H4): intact fibres, a light matrix, plenty of air.
Quality depends heavily on how the peat is harvested. Block-cut peat keeps its natural fibrous structure intact: preserved air porosity, maintained fibrosity, less tendency to compact over time. Milled peat, fragmented at extraction, loses part of that structure. You can find the full comparison in our guide to block-cut vs milled peat.
What does blonde peat do in a growing medium?
In growing media, blonde peat works on three main functions:
- Water retention with air — the fibrous structure holds a large amount of water and keeps it available to the roots, while maintaining wide pore spaces for oxygen. That water/air balance is what separates a substrate that works from one that suffocates.
- Structure that lasts the cycle — being lightly decomposed, it breaks down slowly: the substrate keeps its porosity and drainage for the whole crop cycle, including long ones.
- A base for nutrition — its high cation exchange capacity (CEC) lets it hold nutrients and release them gradually, giving your fertigation programme room to work.
That is why it is the main component of professional mixes: a universal base for sowing, propagation, potting and landscaping, to be combined with perlite, pumice or other materials depending on the crop.
Blonde peat or black peat: what is the difference?
The difference is the degree of decomposition — and it changes how the material behaves:
- Blonde peat is lightly decomposed: fibrous, light, with more air and readily available water. It is the choice for sowing, propagation and for giving structure to mixes.
- Black peat is more decomposed: a finer, denser matrix with greater stability and capillarity, useful for giving the substrate “body” and even wetting, often blended with blonde peat.
In professional practice it is rarely an either/or choice: many mixes combine the two peats to balance air, water and structure for the specific crop.
Which grain size should you choose?
Grain size follows container and cycle. Fine fractions (0–10 mm) give the homogeneous matrix that seedbeds and plug trays need; medium and coarse fractions (10–40, 20–40 mm) provide drainage and oxygenation for large pots and long cycles; 0–40 mm is the universal base to modulate in a blend. Arber’s block-cut blonde peat is available in all four fractions, with a double pH option: standard (naturally acidic) or pre-corrected with dolomitic limestone, ready for direct use in mixes.
pH and what to check on the label
Blonde peat as such has a naturally acidic reaction: an advantage for acid-loving crops such as blueberry, camellia or azalea, while for most crops you work with pre-corrected versions or adjust pH in the formulation. pH, grain size and specific behaviour should always be checked on the product label and technical sheet: those values — not the generic category “blonde peat” — tell you how it will behave in your mix.
Blonde peat in the Arber range
Arber is an Italian producer of professional substrates and products based on block-cut blonde peat: peat of Baltic and German origin, from the same extraction sites year after year, for a batch-to-batch consistency you can see in every delivery. The same raw material is also available loose, as block-cut blonde peat in 250 L bags and Big Bales, for growers who formulate their own mixes.
Always read the product label and technical sheet for grain size, pH and specific instructions for use.
Not sure whether you need loose blonde peat, a blend with black peat or a ready-formulated substrate for your crop? Explore our professional substrates or talk it through with our technical team: contact us.
Frequently asked questions
What is blonde peat used for?
It is the base of most professional growing media: it holds water and keeps it available to the roots, maintains air in the matrix thanks to its fibrous structure, and gives the mix stability for the whole cycle. It is used for sowing, propagation, potting and as the main component of custom mixes.
What is the difference between blonde peat and black peat?
The degree of decomposition. Blonde peat is lightly decomposed: fibrous, light, air-rich. Black peat is more decomposed: fine, dense, with more capillarity and “body”. Professional mixes often combine the two to balance air, water and structure.
Is blonde peat acidic?
Yes, as such it has a naturally acidic reaction — ideal for acid-loving crops. For other crops, pre-corrected versions with dolomitic limestone are used, or pH is adjusted in the formulation. The exact value is on the product’s technical sheet.
Why does the harvesting method matter?
Block-cut peat keeps the natural fibrous structure: more air, less compaction over time, consistent behaviour batch after batch. Milled peat, fragmented at extraction, loses part of its structure and tends to compact sooner.