6 facts to consider when choosing substrate for soft fruit production

There are many options available for soft fruit substrates. Soft fruits grown on substrates are mainly strawberry and raspberry in the Nordics, also the cultivation of blueberries has increased in tunnels. Next, we will share a few things to consider when choosing the substrate for growing soft fruits.

1. Good water holding capacity and adequate airspace

To function effectively, the root system of plants needs optimal air- and water space in the substrate. The pore volume of the substrate must be high. We recommend coarse peat as a substrate for soft fruits. Coarse peat has sufficient airspace between peat particles which ensures healthy root development. Water storage and airspace can also be increased by adding moss and perlite to the substrate mixture. Perlite increases the capillarity of the substrate.

2. Durable structure

The structure of the substrate should last throughout the growing season so that the total pore volume does not deteriorate. Peat fibres and moss can be used in addition to coarse peat to improve the durability and water drainage of the substrate.

3. Suitable pH and good nutrient retention- and buffering capacity

The pH of a substrate should match the needs of the crop being grown. Peat naturally has a low pH, which can be adjusted with lime. In peat-based substrates, this helps create a predictable pH environment throughout cultivation.

Peat also provides reliable water and nutrient retention, supporting controlled irrigation and fertilisation. As blends increasingly include circular raw materials, these properties can change. Water and nutrient management should therefore be adapted to the specific substrate composition and crop.

4. Free from diseases and harmful microbial activity

Strawberry and raspberry are sensitive to various root diseases caused by fungal pathogens, for example, Fusarium, Pythium, and Phytophthora. Root diseases can be prevented with biological and chemical pesticides and by using disease-free plant material. Also, the growing media used in cultivation must be free from these fungi that cause root diseases. Many fungal diseases in the root system like a damp and low-air substrate, so root diseases can be prevented by using a permeable and airy substrate. Useful microbes of peat and moss improve plant resistance to pathogens.

5. Good availability and standard quality

The availability of the substrate is important to the grower. When changing the substrate that has been used at the farm, it requires learning how to manage irrigation and fertilization, for example. Quality substrate does not contain impurities and should be homogenous year after year. The substrate should be free from weeds.

6. Sustainability aspect

Recyclability and environmental considerations are increasingly important for growers. Transport distances, production methods and raw material choices all influence overall sustainability. The right substrate composition balances crop performance with responsible resource use, while irrigation and fertilisation can be adapted to its specific properties.

Would you like to get some beginner’s tips for growing berries in tunnels? Read this article: Beginner’s tips for growing berries in tunnels.