Source: http://www.aquariumplants.co.za

Aquarium Plant Growing Media

Media for Production

There are obviously many growing media available and used in plant propagation. Aquarium plants are a specialized crop and so need a medium that will suite the conditions of where the plant will end up which will be the aquarium. Rockwool or Cultiwool is most commonly used these days. There are still growers that are using other media like synthetic nylon floss, peat moss and types of clays and composted materials like straw and pine bark. Cultiwool is a type of fibre glass often used for heat or acoustic insulation in houses and factories.

Cultiwool is used for a number of reasons:

• It is inhert and so will not pollute the aquarium or affect the pH or water quality when the plants are put in the water.
• Most countries do not allow soil or other organic growing materials to be brought in through their airports and because cultiwool is inhert and not organic there are no problems with phytosanitary requirements.
• Cultiwool has excellent growing media properties like a high air fill porosity, it wets easily and has a high nutrient exchange capacity
• Cultiwool is also a clean and easy medium to work with so helps with planting, cleaning and packaging and transport of plants.

Other growing media than Cultiwool do also have their place especially for plants that are very specific as to their conditions they need. In the aquarium itself cultiwool is not a good medium and we recommend that the cultiwool is removed from the plants roots before they are planted in their final position in the gravel or rock or other position the plant is wanted in.

Media for the Aquarium

When the person receives the plant from his pet store the rockwool should be carefully removed if possible. The plants roots can sometimes be trimmed before planting or in faster growing plants even be cut off to stop rotting in the tank because of damage.

• Organic and Animal material and manures
  I would stay clear of these as they can be unstable when they break down in the substrate.
• Peat moss
  This is also organic but can be useful to try and stabilize the pH of the water it can also help to stop compaction. I would not make more than about a quarter of the mix peat.
• Mineral soils
  These are made up of clays, silts and sands. These are the most useful. In particular the red clay soils as they generally have a high soil nutrient capacity and have a high iron content.
• Commercial mixes
  There are commercially made mixes for the aquarium made by some of the larger companies - often mentioned is commercial laterite which is basically a red clay.

The medium in the aquarium needs to serve as anchorage and as a source of nutrients for the plants. I recommend that for the nutrients a red clay soil should be used mixed with 2mm to 8mm rounded gravel about half clay and half gravel, peat can be added to this as well preferably composted peat. You need to be sure there is no organic matter in the clay soil and that the soil is sterile before you place this mixture at the bottom of the tank about 2cm to 4cm thick or thicker depending on the size of the aquarium.

On top of this a layer place a layer of washed rounded gravel about 2cm to 8cm to stop the clay being disturbed in the water. It is important that the gravel is rounded (like river pebbles) so debris can easily slide through and be broken down in the gravel layer where the bacteria will be. Sharp gravel like silica sand does not allow this and you get a build up of debris on the surface of the gravel that does not break down easily. There are many other types of gravel offered like the synthetic coloured beads etc which I would stay away from for aesthetic reasons.

If you are going to have a sloping gravel bed it is better not to slope the clay layer as it can later level it self through the gravel and cause it to be disturbed. Also try and use rocks or bog wood to rather terrace the levels rather than make slope.

When filling the tank you need to be careful to not disturb the clay - the same goes for planting. it is sometimes easier to plant the plants before you fill the aquarium up.