Wetting agents in substrates

With this article, we’ll have a look at the use of wetting agents in growing media. How are they used? Why do people add them? And what purpose do they serve?

Wetting agents can be used in substrates to improve the wettability and water uptake of the mixture.

How wetting agents improve the re-wettability of your growing media

Under dry conditions, growing media can sometimes develop hydrophobic traits. When materials like peat or bark get a bit too dry, they will have trouble absorbing water. Adding a wetting agent to the mixture reduces the hydrophobic properties. This means the substrate will be easier to rewet and will absorb water again.

Types of wetting agents

There are different materials that can be used as a wetting agent. In general, it’s used in relatively small amounts, as an additive to the growing medium. The best-known type is the synthetic wetting agent in liquid form. However, there are several other types that can be used as well. Some synthetic materials are also available as a granular substance, while you can also use natural or mineral additives that will do the trick.

When to add wetting agents to growing media

Usually, the wetting agent will be mixed in during the substrate production process if needed. That means that the absorption and re-wettability of the growing media are increased from the start of cultivation. The wetting agent will start breaking down during the cultivation period, reducing its effectiveness. The duration of the effective period of a wetting agent varies throughout different growing conditions and methods, as well as for different types of wetting agents.

If you notice that your substrate becomes less easy to wet during cultivation, you can add a new wetting agent to the substrate through your irrigation system. In general, this will only occur in long-term crops. Have a chat with your distributor if you’d like to know more about the wetting agents in Kekkilä Professional substrates or need advice on adding your own wetting agent. Be mindful when adding wetting agents yourself, as some types can become toxic if added in too large amounts.