Nordetect’s Data Farmer Digest is a knowledge center designed to support members of the AgTech industry through shared resources and knowledge. It's where we gather our most valuable learnings on leveraging data and technology for farms. Our goal is to enable growers, consultants, agronomists, and other AgTech professionals to improve their growth strategies.
In this month’s Data Farmer we’re focusing on strawberries’ sensitivity to root zone environment changes and how, with careful monitoring and application of substrates, you can optimize growth and yield.
Choosing the Right Substrate for Strawberry
Strawberries are fickle. Their shallow roots and frequent need for watering can pose challenges to optimal crop output. Any changes in the substrate mixture, or the soil or substance the plants are grown in, can have a detrimental effect on their progression. But with proper management of moisture and oxygen content in the root environment – their physical and chemical environment – you can support stronger development and reduce the margin of error throughout the stages of growth.
The most common substrates for strawberries are coconut coir, peat, and perlite, but how do you choose the magic mix to optimize your strawberry growth? Here are some key considerations for choosing the right substrate for your strawberries:
- Porosity: It’s vital for the roots of your crop to get enough oxygen, which is why porosity is an essential consideration. Your substrate needs to contain enough pores of the right size to allow free airflow through the pot’s entire volume. Your strawberry crop requires high oxygen levels, so choosing a substrate with high porosity is important. For example, a substrate made of only coconut coir will impede plant growth but when mixed with perlite and peat moss, you can create an optimal root zone environment for strawberry growth.
- pH Levels: Root zone pH should hover between 6.0 and 6.5. If the root zone pH exceeds 7.0, plants are likely to experience iron deficiency and stunted growth. To maintain these levels, the substrate pH needs to stay between 5.5 and 6.0. When it comes to managing substrate pH, you have many options. For instance, if your source water is too acidic and it’s affecting pH levels, adding ammonium nitrogen (NH4-N) can stabilize the root zone pH. However, this application needs to be precise. With too much NH4-N, plants will produce more shoots and fewer flowers. On the other hand, source water with a high pH can be supplemented with peat for better results.
- Electrical Conductivity (EC): Electrical conductivity is an indicator of ion concentration in a solution. Since strawberries are more sensitive to salt build-up in the root zone than other hydroponic plants, it’s important to keep the EC below 1.0 dS/m. If the root zone EC exceeds 1.2 dS/m, you may need to flush the root zone with water to clear out any salt accumulation.
- Irrigation: Strawberries are a thirsty crop, requiring frequent hydration. But their moisture content must be balanced so you don’t end up with a soggy root environment. You can calculate the optimal watering volume for your crop based on substrate quality and quantity. However, your watering frequency is dependent on factors such as microclimate, temperature, humidity, radiation, plant size, growing stage, and many more.
- Volume/Container Height: While the substrate is a key component of a healthy crop, the type of container used for plants is equally important. Taller containers can accommodate better drainage and aeration. The recommended volume of the substrate is 2 liters per plant.
Finding the perfect substrate mix can be a complex process, but starting with these five factors gives you key starting points to reach optimal growth. It’s important to keep in mind that the chemical and physical properties of substrates can vary depending on the source, so test the substrate on a small sample before introducing them to your crop.
Want to digger deeper into the best strategies for successful hydroponic or semi-hydroponic strawberry growth? Check out some of our favorite resources and industry experts: