Why you still using perlite?
Perlite is added to mixtures to create better drainage and airiness for the development of strong root systems in plants.
The main tasks
for which the use of perlite is intended:
- adding coarseness to the substrate
- improve soil dry between watering
- working against air pores shrinking
- perlite is messy
- perlite can be expensive, this is particularly the case when dealing with large quantities for professional purposes
- sensitive parts of the machines may break down due to the perlite
- blunt knives used cutting out cuttings during the propagation phase
Usually perlite is used in mixtures at a concentration of 10%.
In this picture, we see that it looks in close-up on a professional substrate for early stages of plant development.
Visually it looks very good, some functions are definitely done as well. However, it is clear that such individual beads of perlite cannot provide good aeration to all the roots that are driven by the plant. In general, such a substrate is more loose than it would be without perlite, but it is far too little.
The concentration of perlite should be much higher. At the hobby level, this can be done when the expenses are relatively small for a few dozen pots. But when it comes to hundreds of cubic meters being developed for professional cultivation, the economic aspect outweighs any benefits.
Sod (block) peat. Vertically harvested peat. One of the key benefits is a better and more durable structure that prevents the soil from collapsing, providing better air and water access to the plant roots. Cost almost twice as much as ordinary milled peat, but much cheaper than perlite.
Looking at the pictures, we see that the structure of this mixture is very similar to that of a plant’s root, with plenty of room for even very small root shoots. Compared to perlite, the total porosity is homogeneous throughout the soil, not just in isolated areas. This structure is long-lasting, the soil does not collapse, and there is no restriction on air access or water flow.
There have been many attempts to make friable (loose) soil structure, including by using specially treated wood fiber mixtures.
But sod peat is still far ahead of all these components, which are often presented as very attractive solutions of “next-generation” growing media.
Sod peat mixtures provide soils with good crumb structure have improved tilth, and more porous, openings (open spaces). These pores allow for gaseous interchange with the atmosphere, and for greater water infiltration.
Basically sod peat was more associated with substrates used for transplanting of large plants like small trees, conifers and perenials.
Only recently, special attention has been given to special substrates with increased aeration and water capacity, which are important in the early stages of plant growth.
Sod peat mixtures offers very good solutions to common issues in growing in small pots.
- Smooth potting ensured: no fibres or impurities that can cause issues.
- Excellent air and water balance for a competitive price.
- Offers a great base for several additives like Controlled Release Fertilisers, Clay, Black Peat etc.
Technical advantages of sod peat mixtures
- Reduced shrinkage: Roots are not reducing air content of the substrate as growing advances, due to an increased amount of solids in the mixture.
- More easily available water). It leads to a better usage of fertilisers and water, because the effect of fertigation will be visible immediately.
- Porosity on optimum level 92-93%. That really makes the difference is the pore size distribution and increased amount of medium-large pores which are the most important to the plant growth.
- Proven benefits in water uptake. Sod peat mixtures takes up water faster and more evenly when re-wetting the mixture. This mainly is a very important characteristics at the start of the growing period, when moisture level is highly important.
- Good for all irrigation systems. Suitable for wet irrigation systems such as ebb and flood, because the mixture has enough air in it.