Guide to different soils. How do you choose and improve the right soil for every plant?

What is soil?

Soil is a mixture of minerals, organic matter, water and air that supports plant growth. It is a vital resource that plays a critical role in agriculture, forestry and other agricultural industries. There are many different types of soil, each with its own unique characteristics and properties. Some of the key factors that influence soil type include the local climate, the type of rock from which the soil is formed, and the amount of organic matter it contains.

Soil has several important functions, including:

• Providing plants with the nutrients they need for growth and development.
• Retaining water and giving plants access to it.
• Providing a place for roots to anchor and supporting the plant.
• Acting as a water filter, helping to purify it as it passes through the soil.
• Providing a home for a diverse community of microorganisms, including bacteria, fungi and insects, which play important roles in the ecosystem.

Different types of soils and substrates (soil additives).

A substrate is the material used as a base for plants. In the context of gardening or aquaculture, a substrate is the material that provides a surface for plant growth. There are many different types of substrates that can be used for plants, and the choice of substrate depends on the specific needs of the plant. Some common types of substrates include:

• Soil: Soil provides plants with the nutrients and water they need.
• Sand: Sand is a dry, granular substrate often used for plants that prefer well-draining soil, such as succulents and cacti.
• Gravel: Gravel is a hard, porous substrate often used for plants that require good drainage, such as orchids.

Types of soils and substrates, composition and properties:

• All Mix: The most widely used soil for growing crops in a controlled environment. A heavily pre-fertilized soil mix. Main ingredients: peat moss, worm, perlite, Mycorrhiza, Pre-Mix. All-Mix creates an optimal environment for your plants to thrive throughout the year. This heavily pre-fertilized soil mix has a self-regulating system that helps regulate the soil pH level and the plant's nutrient regime.

• Light Mix: An organic substrate, ideal for supporting the growth of seedlings, young plants and cuttings. Blended to provide optimal drainage throughout – an essential property if you use automatic irrigation systems.

• Pre-Mix: Organic dry fertilizer. It is a blend of different organic ingredients and is resistant to fungal diseases. Pre-Mix combines the qualities of different organic fertilizers, micronutrients and fungi – all in the right quantities.

• Worm Humus: BioBizz Worm Humus is an organic soil improver. Also known as “vermicast”, it is the end product of decomposed material excreted by earthworms. This high-quality organic compost is made from 100% pure earthworms, strictly laboratory-tested to ensure that it contains no agricultural waste or compost. Worm-Humus is ideal for refreshing All-Mix, adding to already used soil mixes or preparing subsoils.

• Bio Terra Plus: BIOCANNA Bio Terra Plus is made from 100% natural materials and can be used for organic plant cultivation. It consists of different categories of peat, bark and coconut fibres. Using perlite is no longer necessary to obtain an oxygen-rich, well-draining soil mix.

• Terra Professional: CANNA Terra Professional is a nitrogen-rich soil mix. It contains a combination of improved dark peat, granulated peat moss and perlite. Exceptional, high-value organic ingredients, such as loose peat moss, which contains no disease-causing organisms.

• Coco Mix: BioBizz Coco Mix is made from 100% organic coconut fibres. It works as a substitute for mineral wool in the cultivation of all types of hydroponic crops. To become this substrate, the coconut fibres are first decomposed for a period of time to soften the tough fibres. They are then rinsed with clean water, dried and shredded to become light and airy.

• Vermiculite: Vermiculite is a natural, soft and porous material obtained by expanding mica. It has a high cation exchange capacity – this helps gradually release nutrients such as potassium, calcium, magnesium, iron, silicon and other micronutrients. It retains up to 4 times more water while protecting roots from rot.

• Perlite: Agroperlite is expanded perlite used in gardening. It is added to clay soil to reduce the risk of rot and to sandy soil to help retain moisture. It facilitates the even distribution of fertilisers to the roots, while its neutral pH counteracts excess soil acidity. Perlite “likes” air, while vermiculite likes water.

• Expanded clay: The benefits of expanded clay lie in its porous structure. This makes it easy for nutrients, oxygen, water and fertiliser to penetrate every part of the plant. Its porous structure provides optimal conditions for plant growth: it improves soil structure, protects roots from drying out in hot weather and from mould on damp days, and reduces the risk of plant diseases and pests.

How do we know which soil is suitable for our plants?

There are several key factors to consider when choosing suitable soil for your plants:

• Nutrient content: Different plants have different nutrient requirements, and it is important to choose soil that meets the specific needs of your plants. For example, some plants may require higher nitrogen levels, while others may prefer more phosphorus or potassium.
• Soil pH: Soil pH can affect the availability of nutrients to plants. Most plants prefer a soil pH between 6.0 and 7.0, which is a slightly acidic environment. Some plants, such as blueberries, prefer more acidic soil with a pH below 6.0, while others, such as lilacs, prefer more alkaline soil with a pH above 7.0.
• Drainage: Proper drainage is important for most plants because it helps prevent waterlogged soil, which can lead to root rot. Choose soil with good drainage capacity or use a potting mix that includes ingredients such as perlite or vermiculite to improve drainage.
• Texture: Soil texture can also affect its ability to retain water and nutrients. For example, clay soil generally retains water and nutrients well, but it can become compacted and drain poorly. Sandy soils generally drain well, but may not retain water and nutrients as effectively.

The importance of soil pH

Soil pH refers to its acidity or alkalinity, with pH 7 being neutral. Soil pH can have a significant effect on the availability of nutrients to plants and on the overall health of the soil ecosystem. Soil pH can be influenced by a range of factors, including the type of rock from which the soil originated, the types of plants growing in it, and the presence of certain chemicals or materials, such as fertilisers or lime. Soil pH can be measured using a soil-testing kit, available at most garden centres.

If the soil pH is outside the optimum range for a particular plant, this can affect the plant’s ability to absorb nutrients and lead to deficiencies or other problems. Soil pH can be adjusted to a plant’s optimum range by adding materials such as lime to raise pH or sulphur to lower pH.

How can we improve our soil?

Here are 10 ways to improve your soil:

1. Add organic matter: Adding organic matter, such as compost or well-rotted manure, can help improve soil structure, making it easier for plants to absorb water and nutrients.
2. Use cover crops: Cover crops, such as clover or grasses, can be grown between seasons to help add nutrients to the soil and improve its structure.
3. Rotate different crops in the same soil: The Crop Rotation method involves growing different types of crops in the same area each season. This can help prevent nutrient depletion and reduce the risk of pests and diseases.
4. Add mulch: Mulch, such as wood chips or straw, can be added to the soil surface to help retain moisture, suppress weeds and add nutrients to the soil as it breaks down.
5. Use fertilisers: Fertilisers are important to provide your plants with all the necessary elements in the right quantities. This allows your plant to develop at its maximum rate without showing deficiencies.
6. Add lime: Lime can be added to the soil to help raise pH and make nutrients more available to plants.
7. Use raised beds: Raised beds can help improve drainage and allow better control over the soil mix, making it easier to grow a wider range of plants.
8. Plant cover crops: Planting cover crops, such as legumes or grasses, can help add nutrients to the soil and improve its structure.
9. Use organic pest-control methods: Using organic pest-control methods, such as natural predators or trap crops, can help reduce the need for chemical pesticides, which can harm the soil ecosystem.

Does every substrate contain nutrients?

Not every substrate contains nutrients. Some substrates, such as soil, contain a mixture of minerals, organic matter and other nutrients that are essential for plant growth. Other substrates, such as sand or gravel, may not contain significant amounts of nutrients and need to be enriched with fertilisers and other nutrient materials to support plant growth.

Conclusion

Soil is essential for healthy plant growth, providing plants with the nutrients, water and support they need. Understanding the different soil and substrate types and their characteristics is key to successful plant cultivation. Proper soil care and the use of sustainable farming practices can help maintain healthy soil and a successful harvest.