How to choose a substrate?
Substrate is the first decision you will make when choosing a method to grow your plants. When making this choice, you should mainly think about several factors:
• Drainage and aeration of the root system
• Nutrient content and retention of nutrients you add
• pH levels
Substrate options generally boil down to:
• Organic soils (heavily fertilized soils or lightly fertilized soils)
• Inorganic substrates such as perlite, expanded clay, stone wool
• Organic soils in combination with inorganic (inert) substrates, which is the most common substrate mix
• No substrate (the Kratki method is popular, which is a variant of a hydroponic system - where plants live in a solution of water and nutrients)
Growing in organic soil
We'll start with the pros of growing in soil. First of all, soil is the natural environment in which plants live. It is rich in organic nutrients and trace elements such as nitrogen, phosphorus, potassium, calcium, magnesium, sulfur and iron. These and other elements are absorbed by plants more slowly compared to other inert substrates or in the absence of substrate. This is not bad for beginning gardeners because:
• Extends the period in which nutrients are available to the plant and thus reduces the risk of insufficient fertilization
• On the other hand, it reduces the risk of "burning" in case of excessive fertilization
The taste and aroma of crops grown in organic soil is usually the gold standard for gardeners. While other substrates and growing methods increase yield, the quality of soil-grown fruit is what all growers strive for.
The disadvantages of growing in soil are:
• The structure of soils and their qualities can vary greatly. For novice gardeners, this carries the risk of applying advice adequate for one type of soil to another.
• Growth in the growing season and the flowering period of plants in soil is usually weaker compared to those grown in soilless substrates.
• The soil is susceptible to pests and diseases.
• Nutrient and pH control is more complex with organic soils because they influence these factors. Whereas with inert substrates such as expanded clay, rockwool, perlite and even coir, the pH and nutrient values are only affected by what the gardener does.
-> Read more about soil types and their benefits in our Soils collection.
Growing in hydroponic systems with expanded clay, perlite and rockwool
Although manual cultivation in soilless substrates is possible in theory, it is not widely practiced in practice. Therefore, we will talk generally about growing in hydroponic systems, where these substrates are used most often.
The benefits of growing plants in inert substrates are mainly threefold:
• The gardener has complete control over the environment – pH, EC, nutrients and moisture.
• In the presence of an experienced gardener, we can expect faster vegetation, more abundant flowering and greater yields.
• The substrate can be reused many times.
The disadvantages of hydroponic systems are related to their pretentiousness:
• There are many factors to consider when mixing the nutrient solution and these should be monitored regularly.
• Most hydroponic systems rely on the availability of direct current – for those gardeners who have chosen remote areas this is not always possible.
• And last but not least, the investment in a hydroponic system is higher compared to traditional cultivation.
-> See more about soilless substrates in our Inert Substrates section.
Growing in coconut (coco coir)
Coconut substrate can be used with hydroponics where it will take on some of the characteristics we have described in the above paragraph.
However, the benefits of coconut are substantial:
• The coconut substrate holds water wonderfully, but without causing root rot.
• It has a high cation exchange capacity, which means it also retains nutrients from your fertilizer very well.
• Coconut fiber is a renewable and ecological product.
• Coconut can be sterilized and reused (economically efficient) or composted.
• This substrate is light and easy to work with.
Unfortunately, the coconut is susceptible to pests and diseases and is not very effective in anchoring the plant - when growing with coconut it is advisable to use supporting structures.
-> See more about coconut substrates in our coconut section.
You can always count on assistance from the experienced team atgrowshop gardener, when choosing soil or substrate for your plants.
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