Soil or coconut growing substrate? Choose the right one for your garden!
Choosing the right substrate is one of the most important decisions you will make as a grower. Whether you choose soil or coconut will affect not only plant health, but also the choice of fertilizers, the method and frequency of watering, and many other aspects of plant care. In the following article we will introduce you to the advantages of growing in soil and coconut substrates and advise you which one to choose.
Soil and coconut substrates have a lot in common, but they also offer unique advantages and challenges. The choice of a suitable growing medium ultimately depends mainly on your and the plants' needs. Deciding is easier if you familiarize yourself with the strengths and weaknesses of each growing substrate.
Soil-based substrates
The main component of soil (horticultural) growing substrates is earth/soil, which can be enriched with additional components such as peat, compost, perlite, coconut fibers, fertilizers and more to further modify their properties. Different types of soil can meet the specific needs of plants, and horticultural substrates are suitable for a wide range of species, from vegetables and fruit to ornamental flowers and herbs.
Advantages of soil growing substrates
- High nutrient availability
Horticultural substrates are rich in basic nutrient elements NPK (nitrogen, phosphorus, potassium) and trace minerals that occur naturally in soil. The amount and availability of these nutrients is influenced by the substrate composition and microbial activity during the growing cycle. Some soil mixes are supplemented by manufacturers with slow-release fertilizers that increase their fertility.
- Rich microbial life
Soil is a natural habitat for a multitude of beneficial microorganisms such as bacteria, fungi, protozoa and others that play a significant role in breaking down organic matter, fixing nitrogen and increasing nutrient availability to plants. Many plants form symbiotic relationships with soil microbes, for example with mycorrhizal fungi, which improve water and nutrient uptake.
- Excellent water retention
Soil retains water very well, which reduces the need for frequent watering. Most horticultural substrates contain, in addition to soil, other materials that adjust the mixture's retention properties according to the grower’s needs.
- Balanced aeration and structure
Quality soil mixes hold a large amount of water while remaining sufficiently porous to allow oxygen access to the roots. Soil is heavier than other growing media and provides plants with solid support, even when grown in pots or in windy locations.
- Naturally stable pH
Soil has a natural buffering capacity and helps maintain a stable substrate pH, which is essential for nutrient availability and overall plant health.
- Price and availability
Soil substrates are widely available and often cheaper compared to other growing media.
You may be interested in: How to choose a horticultural substrate
Coconut substrates
Coconut substrates are modern growing media made from coconut fibers and are increasingly popular as an alternative to classic soil mixes. They come in various forms and are suitable for a wide range of horticultural techniques, from container growing to hydroponics and irrigation systems. Coconut substrates are versatile and suitable for cultivating most plant types as well as for cloning, germination and seedling propagation.
Advantages of coconut growing substrates
- Low in nutrients and pH-neutral
Coconut fibers contain minimal amounts of nutrients, so growers can provide plants with precisely the nutrition they need through fertilizers. This precision helps control plant development and achieve maximum yields. The neutral pH of coconut substrates also makes it easy to adjust and maintain pH in the optimal range for nutrient uptake.
- Resistance to pests and diseases
Pests and pathogens commonly found in soil are less often encountered in coconut substrates. This significantly reduces the risk of infestation, which is particularly appreciated in enclosed growing rooms and grow boxes. Many coconut substrates also contain beneficial fungi of the Trichoderma genus that protect plants from harmful microorganisms.
- Excellent retention properties
Coconut fibers can retain up to ten times their own weight in water while effectively draining excess irrigation. This provides roots with consistent moisture and prevents root rot and other problems associated with waterlogging. This balance allows growers to water and fertilize plants more frequently.
- Excellent aeration
Coconut substrates have a porous structure that ensures excellent aeration, which leads to rapid development of the root system. The combination of good water retention and high aeration supports vigorous growth.
- Buffering capacity
Compared to hydroponic systems and media, coconut substrates have good buffering capacity and help stabilize pH fluctuations that can stress plants and create nutrient uptake problems. They allow the grower small mistakes in fertilizing and watering without immediate negative effects.
- Easy storage and handling
Coconut substrates are lightweight and can be compressed into compact blocks, which facilitates transportation and storage.
You may be interested in: Guide to coconut substrates
Coconut substrates
Coconut substrates are modern growing media made from coconut fibers and are increasingly popular as an alternative to classic soil mixes. They come in various forms and are suitable for a wide range of horticultural techniques, from container growing to hydroponics and irrigation systems. Coconut substrates are versatile and suitable for cultivating most plant types as well as for cloning, germination and seedling propagation.
Advantages of coconut growing substrates
- Low in nutrients and pH-neutral
Coconut fibers contain minimal amounts of nutrients, so growers can provide plants with precisely the nutrition they need through fertilizers. This precision helps control plant development and achieve maximum yields. The neutral pH of coconut substrates also makes it easy to adjust and maintain pH in the optimal range for nutrient uptake.
- Resistance to pests and diseases
Pests and pathogens commonly found in soil are less often encountered in coconut substrates. This significantly reduces the risk of infestation, which is particularly appreciated in enclosed growing rooms and grow boxes. Many coconut substrates also contain beneficial fungi of the Trichoderma genus that protect plants from harmful microorganisms.
- Excellent retention properties
Coconut fibers can retain up to ten times their own weight in water while effectively draining excess irrigation. This provides roots with consistent moisture and prevents root rot and other problems associated with waterlogging. This balance allows growers to water and fertilize plants more frequently.
- Excellent aeration
Coconut substrates have a porous structure that ensures excellent aeration, which leads to rapid development of the root system. The combination of good water retention and high aeration supports vigorous growth.
- Buffering capacity
Compared to hydroponic systems and media, coconut substrates have good buffering capacity and help stabilize pH fluctuations that can stress plants and create nutrient uptake problems. They allow the grower small mistakes in fertilizing and watering without immediate negative effects.
- Easy storage and handling
Coconut substrates are lightweight and can be compressed into compact blocks, which facilitates transportation and storage.
You may be interested in: Guide to coconut substrates
Comparison of coconut and soil substrates
When comparing coconut and soil substrates we can notice several differences. While soil naturally contains a wide spectrum of nutrients available to plants, coconut substrates are in that sense “blank.” On the other hand, coconut substrates offer better retention properties and aeration than soil mixes. Working with soil can be more demanding than with clean, lightweight coconut fibers. When deciding which growing substrate to choose, consider three main factors: the environment, the growing method, and plant nutrition.
- Growing environment
Soil: Suitable for outdoor and indoor growing under artificial light, especially for plants that can benefit from microbial activity and high nutrient content, such as tomatoes, peppers and more.
Coconut: Suitable for outdoor and indoor growing under artificial light, in hydroponic systems, and especially for plants that require a well-aerated substrate, such as herbs and ornamental flowers.
- Nutrition
Soil: When cultivating plants in soil mixes you can use mineral or organic fertilizers with slow or fast release as well as nutritional supplements. Horticultural substrates are also suitable for organic and permaculture growing and the “living-soil” method.
Coconut: When growing in coconut substrates you can use mineral or organic fertilizers with slow or fast release as well as nutritional supplements. Fertilizers for coconut growing typically contain increased amounts of calcium and magnesium or these nutrients need to be added to the watering solution in the form of a CalMag additive.
- Growing method and environment
Soil: Soil mixes are a universal growing medium that can be used for any growing method and are suitable for both indoor and outdoor use. They are also an excellent choice for cultivating plants in large containers and fabric pots.
Coconut: Due to faster drying, coconut substrates are more suitable for indoor use and as a medium for hydroponic growing. When growing outdoors it is important to water plants regularly so that the fibers do not dry out completely and lose their retention properties.
Want to learn more about different types of growing media? Read our Guide to growing substrates