In the Lensli Academy we regularly inform you about practical situations that we encounter in the sector, we talk about insights gained in practice, we give you cultivation tips and we share our knowledge about other interesting substrate-related matters.

The rules regarding substrate are further tightened under market pressure. England, among others, is tightening the rules for substrate as of January 1, 2026. The requirement? No more peat in the substrate, but only substrates based on more circular, renewable raw materials. Changes are also noticeable in the supply side of raw materials and we face challenges. There is currently less peat available; for example, Ireland has stopped peat extraction. In response to these developments and future trends, Lensli has gained a lot of knowledge and experience in recent years in growing in peat-reduced and peat-free substrates.

What makes substrate sustainable?
Everyone has their thoughts on this. This often involves peat-poor or peat-free substrate, but in fact it goes one step further. Most likely, recyclable raw materials will also eventually have to be used, such as compost. After all, the ultimate goal of a sustainable substrate is the CO2 savings it produces.

Peat substitutes
There are 3 major product groups to replace peat. These are wood products (bark and wood fiber), compost and of course coconut. There are also some other options, such as perlite, rice husks or pumice stone, but these are products that are mixed in relatively smaller quantities.

What should a grower take into account when using substrates with circular and renewable components?
Peat has a few properties that make growing relatively easy. For example, peat has a buffer that allows it to retain water and nutrients well. Peat actually has everything it takes to make a plant grow well. With peat replacement and reduction we will miss these beautiful properties. In recent years, Lensli has conducted a lot of research into the (im)possibilities of peat-poor and peat-free substrates.

Our experiences
From these experiences we can indicate the following things that a grower should take into account when considering a low-peat or peat-free substrate:

Water and nutrient buffer
The very first thing that must be taken into account is the less buffer for water and nutrients in a peat-poor or peat-free substrate. Make sure that plants can be treated separately, because, compared to a peat-containing substrate, on average about 35% more water and nutrition are required. This fact should be taken into account when starting fertilization. Raw materials in a peat-poor or peat-reduced substrate extract relatively more nitrogen and this must be compensated. If this is not done, you will soon have yellow plants after the start, which are difficult to get color during cultivation.

Difficult pH control
Controlling pH is more difficult with a peat-poor or peat-free substrate. Due to the raw materials used as peat replacement, the pH is almost always above 6.0. Therefore, when fertilizing the new substrate, the input and extraction of nutrients by the peat replacement components must be taken into account. Some raw materials, such as compost, provide nutrients such as potassium and manganese, while others, such as wood fiber, extract nutrients such as nitrogen. It can also be useful to examine the track mix. What do we already have enough of from the input of raw materials, and what are we lacking? The use of another iron chelate may also be advisable.

Some raw materials and additives significantly increase the pH, such as compost and clay. And a combination of these is often not necessary. The dosing of lime for the pH in the root ball is usually much lower in peat-free mixtures, or is not even necessary.
We usually recommend lime nitre to compensate for the nitrogen immobilization that some raw materials entail. This is because it works immediately and also provides absorbable calcium.

It is always important to look carefully at which major and trace elements are present for the plant in the water-soluble part of the substrate. This can easily be done via a head and trace analysis at Eurofins, for example. As long as the balance of the elements is correct, many crops can also develop well at a higher pH. Consult with your Lensli account manager or product manager to find out what is useful in your own situation.

More background information in our knowledge base 
Peat-free and peat-poor substrates are sensitive to sapotrophic fungi. You can read more about these fungi and how to deal with them in our knowledge base. Click here to go to this item.

Using compost can cause the substrate to “heat”. This can cause the temperature of the substrate to rise. You can read more about what this means in concrete terms here in our knowledge base.