Oxygen Plants

Oxygen plants grow quickly and keep the pond clear and algae-free. They grow underwater and absorb nutrients from the water via the leaves and release oxygen. They are therefore an important basis for the natural balance in the pond and are extremely useful for keeping the water clear and healthy.
The rate of growth is determined by the presence of light, temperature (12-25°C), nutrients, water quality and CO2. If they grow poorly or not at all, the cause can usually be sought in the water quality and too low supply of CO2. The chance of algae growth then increases rapidly. With a water test you can examine the water quality.

What oxygen plants do you choose?

Not all oxygen plants produce oxygen throughout the season. Therefore, variety and variation in these types of plants is important. This makes the chance of algae growth the least. For spring and winter is water fringe (Ranunculus aquatilis). Highly recommended for summer and fall are hornwort (Ceratophyllum demersum), pondweed or waterweed. Other well-known species are limpet stem (Hippuris vulgaris) and water violet (Hottonia palustris).

In existing ponds with a lot of algae – green water and/or filamentous algae – it is not wise to place oxygen plants. The algae take up all the CO2 present in the water, and therefore the new oxygen plants cannot grow properly. Therefore, ensure an algae-free start and proper water hardness before placing oxygen plants.

Placing oxygen plants

Place the plants under water, in lelite and cover that with growth substrate. In nature, these plants root directly into the soil. In most ponds this is difficult because there is foil on the bottom or a pond container has been used. Therefore, always use pond baskets or make a planting bed from lelite and cover with growth substrate (a planting bed cannot be walked on because of delicate roots). If you place oxygen plants in a pond with good water quality (mineral-rich, i.e. hard water) and sufficient CO2, they will keep the water clear and algae-free. Opinions vary on the amount of oxygen plants for clear water, but a rule of thumb is 5 bushes per 1,000 gallons of water.

When do you plant oxygen plants?

It is important to place oxygen plants in the pond as soon as possible after start-up, so that algae do not have a chance. An exception to this is starting up a pond in the winter. This is because plants and algae do not grow in winter. New ponds contain few microorganisms in the beginning and therefore have a low CO2 supply. To increase the CO2 content, so-called CO2 Tabs can be added.

Preferably plant the plants during their growth period, between April and June. After placement and with enough plants, they will keep the water clear and algae-free.

Oxygen plant maintenance

In summer, cut away the top half of the oxygen plants if the pond seems to grow completely dense. In fall, all oxygen plants may be cut away to 10cm above the bottom. Caution! Never use a rake during the operations otherwise you will also remove the roots!
Special growth balls have been developed for local fertilization of the plants.

Oxygen plants give a bright look to ponds! You buy them at garden centers and pet and pond specialty stores.