A DRY SUMMER LEADS TO DRY PEAT

This summer 2023 has been a dry harvesting season, which causes the product peat to go in the stockpile at a lower moisture content than usual. This can be beneficial for loading more volume per load as less water is transported. But the user of the peat or the substrate containing this peat should add water to the product supplied probably differently than usual. The WOK (Water Absorption Characteristic) of the product hasn’t changed, but the speed of the water uptake will be different and most likely slower than with a product at a higher moisture level. The WOK analysis developed by RHP provides insight into the water absorption rate of substrates. The WOK analysis examines the speed at which a substrate or peat absorbs water from an (air) dry situation. This provides insight into how a substrate absorbs water in a crop.

Growing Situations

With dry cultivation, ebb and flow cultivation and cultivation on an irrigation mat, the moisture content of the root balls can vary greatly. In these growing situations, quick and easy water absorption from the substrate is of great value. Limited watering or changes in the composition of the substrate mixture or the water regime can have major consequences for the water distribution in the pot (root ball), for example areas that are too dry.

Even Crop Development

The rate of water absorption can vary greatly per substrate. If a substrate can absorb water quickly from dry conditions, this can prevent problems with root balls drying out. Smooth water absorption helps to distribute the water and fertilizers evenly in the root ball. And that in turn contributes to good, even crop development.

Insight into Water Absorption Rate

Each part of a recipe has its own rate of water absorption. Insight into these values and how the raw materials and additives react to each other, is important to choose a substrate that best suits the cultivation situation and method of watering. The WOK analysis results provide insight and thus contribute to better crop management.

WOK Analysis

WOK (Water Absorption Characteristic) is a laboratory analysis in which a substrate is brought to a very low moisture content in a standard manner. The samples are then placed on a layer of water of a few milimetres for 24 hours. This examines how quickly the substrate absorbs water under dry conditions. The water absorption is measured continuously. The time in which the substrate reaches 50 percent of its potential water absorption is decisive for the water absorption characteristic.

WHAT TO DO IF THE PRODUCT IS DRYER

We advise to give smaller amounts of water and to increase the frequency of watering. If you have been supplied with peat and you need to mix it into a substrate, add water slowly, in the form of fine drops or in the form of shower or through sprinkler nozzles during the mixing process of the substrate; and if possible, for mixing when the peat is in bulk storage. This is a common way of adding moisture to a substrate. The dryer product is not different in comparison to a moister product in many ways, but to reach the level of a certain moisture content the road towards that is slightly different. A good start of the culture by moistening the peat step by step before potting, leads to a good result.