In gardening stores you will find a large selection of various substrates and soil for growing plants. You can buy universal soil or specialized substrates for a specific purpose, eg for conifers, for flowering plants, for the production of seedlings, etc. A good substrate is expected to be permeable, while retaining water and nutrients. It should also be free from pathogens and pests. In order to obtain substrates that meet all these requirements, ingredients are added to them to improve their properties. Below we present the most popularadditives for horticultural substrates
Additives for horticultural substrates - expanded clay
Agro- and hydrogels- are multi-molecular, cross-linked, insoluble polymers, characterized by the ability to absorb water. They are usually sold in the form of powder or granules to be mixed with the soil. After absorbing water, they swell and take the form of gel balls. They improve the physical properties of the substrate and retain water. They protect plants from drying out and allow to reduce the frequency of watering. They are widely used both in the garden (added to the soil when setting up a lawn or planting new plants) and in potted cultivation (they reduce the flow of water onto the stand under the pot, retaining moisture in the ground). More about hydrogels in the article How to use hydrogels?
Expanded clay- these are light, porous, irregular granules that are formed in the clay firing process.When added to garden soil, it loosens its structure and improves aeration. It is an excellent material to be used as drainage at the bottom of the pot, as well as as a mulch material, placed on top of the soil around the plants. The stores offer expanded clay of various sizes of granules. The diameter of the smallest granules is about 0.5 cm, and the largest - up to 2 cm. Expanded clay with larger granules is perfect for hydroponic cultivation. Unfortunately, it does not retain water or nutrients.
Perlite- is a mineral of volcanic origin, with a whitish shade. When added to the ground, it helps to loosen them, aerate and fluff them. It is valued because it easily stores and gives off water, thanks to which the soil mixed with perlite dries up more slowly and the plants have better access to moisture. It is often added to poorer quality peat substrates. It is usually used in the proportion of 1 liter of perlite to 3 liters of substrate.
Sand- allows to increase the permeability of the garden soil and loosen its structure.Coarse-grained river sand works best in this role. Mixed with peat in the proportion of 1: 1, it is a substrate for rooting plants or covering sown seeds. In order to improve the permeability of the garden soil, 5 to 10% of sand is added.
Pumice- is a volcanic igneous rock. It is available in a fraction of 3-8 mm or 10-20 mm, in the following colors: gray, brown or bluish. It is characterized by high porosity, durability and a neutral pH. It is an excellent additive that loosens the ground. It is mainly used in the cultivation of orchids and succulents, as well as in hydroponic cultivation.
Coconut fiber- is a 100% organic material, obtained from the shells of coconut palms. It has very good physical properties. It has a large water capacity, high porosity and a pH close to neutral. When added to the substrate, it provides aeration and even distribution of moisture. It is light and allows you to reduce the weight of the plant pots.It is sold in the form of pressed cubes. Before use, they should be poured with water to make them swell. It can be used in place of flower soil, peat or normal garden soil, and also as an admixture to the substrate. They are used in the cultivation of potted plants, bedding plants, as well as for the production of seedlings.
Gravel and stone grit- allow to improve the permeability of the substrate. They are also used as a drainage layer at the bottom of the pot or as a mulch layer. They are much heavier than the. e.g. expanded clay, and therefore used as a drainage layer, additionally adds weight to the pot.
