Aquatic plants: which substrate to choose?

When the first tarpaulins were built, the choice of substrate was often the same: a mixture of peat, clay, earth, and sometimes sand. Minerals or fertilizers were often added to these mixtures. The negative point in the choice of these materials, however, was that the nutrients got directly into the water. As a result, the plants no longer absorbed them. The choice of substrate for aquatic plants is therefore more technical than it seems. Here are all our tips for making a good choice.

Substrate selection for aquatic plants

Note that the water quality of the pond depends on the type of substrate used. Therefore, it is better to choose a plant medium. Lime-free gravel or sand is fine. You should also be aware that peat added to the substrate will cause methane to form in the water. However, this gas would prevent air intrusion and thus reduce the activity of bacteria essential for aquatic plants.

aquatic plants substrate water lily
Credits: iStock

Soil quality of a “special aquatic plant”

Ready-to-use potted lands can be found for aquatic plants, but they often contain peat, which is not recommended, as we explained earlier. However, you can improve it by adding sand, for example. This indeed increases the permeability of the soil and thus the growth of bacteria. You can also add a 10 cm layer of gravel on top of this mixture. This will help prevent the peat from rising.

Choice of fertilizer and water

It is not necessary to add fertilizer, as the medium already contains all the nutrients needed by the plants. When the pool is full, dead leaves, larvae and certain rotting plants settle there. They then form natural fertilizers.

Finally, remember that water quality is also chosen. It is indeed necessary to avoid tap water and choose rainwater. Adequate storage can be used with the collector.