Peat has been the basis of most potting mixes and substrates for decades. It is homogeneous, holds water well, contains sufficient air and is easy to bring to the desired pH and nutrient level. Yet its use is under pressure. Peat extraction releases carbon that has been stored in the ground for a very long time, and buyers, retailers and governments are increasingly asking for less peat in the supply chain. For many growers, the question is therefore no longer whether they will use less peat, but how to do so without putting the crop at risk.
What do we mean by peat-reduced and peat-free?
There is no legal definition. We use the following classification:
- Peat-based: peat is the main component, more than half of the volume.
- Peat-reduced: no more than half is peat, supplemented with alternatives.
- Peat-free: contains no peat.
We state the exact composition for every product, so you do not have to rely on a label.
What replaces the peat?
No single raw material does everything peat does. A good peat-reduced or peat-free substrate therefore combines several components, each with its own role:
- Fine coir holds a lot of water, quickly takes it up again after drying out and is structurally stable. The main replacement for the water function of peat.
- Coarse coir adds air and structure and hardly slumps.
- Wood fibre is light and airy and improves rewetting, but breaks down faster and locks up nitrogen.
- Bark provides structure and air and has a slightly acidifying effect.
- Perlite adds air permanently without breaking down.
- Compost is used in some mixes for buffering and soil life, but requires careful quality control.
What changes in the crop?
A substrate with less peat behaves differently. The differences are perfectly manageable, but you need to know them.
Irrigation. Mixes with wood fibre and coarse coir let water through faster. The top layer dries out sooner, while the bottom of the pot may still be moist. If you water by eye, you will soon be watering too often. Lift pots, weigh them or use a moisture meter to determine the actual moisture status. Watering more often with less each time often works better than watering rarely and heavily.
Feeding. Wood fibre locks up nitrogen in the first few weeks as micro-organisms break the material down. That is why wood fibre-rich mixes contain extra nitrogen. Unbuffered coir can release potassium and sodium and bind calcium and magnesium; that is why we use washed and buffered coir in our mixes. Check the EC more often than you are used to during the first few weeks.
pH. Peat naturally has a low pH and is limed. Coir is roughly neutral. Mixes with a lot of coir therefore respond differently to lime and to the composition of your irrigation water. Measure the pH at the start and after a few weeks of growing.
Structure over time. Wood fibre breaks down faster than peat or coir. For short crops this is rarely a problem; for crops lasting several seasons, choose a mix with more stable components such as coarse coir and bark.
A step-by-step transition
Do not switch your entire business from a fully peat-based to a peat-free substrate in one go. A gradual approach gives you the chance to learn:
- Start with a peat-reduced mix in part of the crop, alongside your trusted substrate.
- Record the starting values: measure pH and EC at the start and then weekly.
- Adjust irrigation deliberately and keep a record of what you do.
- Compare growth, rooting and uniformity at the end of the crop.
- Only reduce the peat content further once the results are consistent.
Help with the transition
Every business has its own combination of crop, pot size, irrigation system and climate. What works for your neighbour will not necessarily work for you. In an advisory consultation or during a site visit, we look at your situation with you, and with a bespoke mix you can reduce the peat content step by step. A substrate analysis during the crop helps you spot deviations early.
