Plant breeding techniques

Keeping, maintaining, and ultimately propagating your aquarium plants is truly a joy, and it starts with a good substrate. The term 'substrate' refers to the planting medium used on the bottom of an aquarium. Similar to soil in a garden, substrates are needed by plants in order for them to root, obtain nutrients, and propagate.In natural environments, the substrate is typically slightly warmer than the water. It is also full of nutrients and dense. These things help the plants to root better, they receive better nutrition, and the warmer root conditions help in the growth of the plants. It is important to determine which soil is best for plant growth in the aquarium, maintaining the substrate once it is set is usually fairly simple. Not much is needed. This is due to the normal activity of the aquarium. The fish and plants produce and release enough organic products, that then collect in the substrate, and in turn help the plants grow.

Colored (aquarium) Gravel: This is much like the common pea gravel and is also not ideal for plants. Again it is fairly loose and allows for easy water flow through it.

It can be mixed with other substrates for a visual variation, and will work well as a top layer over finer substrates. Light gray gravel is not a good choice however, as it causes distress in the fish due to how strongly the light is reflected off of it.

Calcius gravels: Crushed coral and other calcius sands or gravels that are offered for saltwater aquariums are high in calcium. They should be avoided unless you need a high pH and water hardness, few plants want this. These gravels work well in freshwater fish aquariums that are designed for African cichlids that need these high levels.
Sand: Sand is very fine, often even dusty. The 'silver sand' sold in aquarium shops is totally inert. Sand will compact and prevent any water movement resulting in a lack of oxygen.

Though sand can be used in a thin layer as a rooting medium for some plants, you will want to stir it occasionally to keep it from compacting. It is generally used as a base layer over heating cables.

Soil, Potting Soil: This substrate can be tricky to use as it can have too many nutrients and it may encourage algae growth. Also it is difficult to keep it from clouding the water.

Potting Soil is sometimes used as a thin nutrient-rich substrate layer and covered with a heavier top substrate. It has also been effectively used in permanent pots that are covered with a heavier top substrates. The potted method can be used in aquariums with undergravel filters.

Nutrient-rich Substrates: These are a long term source of nutrients that are vital to the plants. They should be used in limited quantities of either very thin layers between other substrate layers or as small pellets placed by the roots of plants. See the Nutrient rich layer described above for some of these products.