When planting an aquarium one has to take into account many factors to successfully plan your planting arrangement. First of all, you'll want to use a substrate that is not too large or too small a grain size. Plants must be able to move through it with their roots, but have sufficient support to either spread runners or take root and grow upward as stem plants do. Generally speaking this would be 3-5 millimeters or .12 to .20 inches in size.
You'll also want to have adequate space for growth, especially with plants such as Swords and Cryptocornes and Aponogetons. I recommend three to four inches in depth, and if possible more depth in the back sloping to the front. You can use any number of the excellent substrate products on the market (another subject) or you can obtain actual gravel called Red Flint. It comes in multiple sizes and should be seeded with Laterite, an iron rich substrate additive that aids in plant growth by feeding the roots.
The longest lasting way to add Laterite to the gravel substrate is to lay a thin layer of gravel down, then a layer of Laterite, and then the remaining gravel. You can then add the water slowly pouring the water onto a clean plate, so as not to disturb the substrate. This will minimize the cloudiness from the iron-laden Laterite in the substrate.
Next you must have a plan, preferably written, as to what plant will go where and next to what other plant considering colors or shades, and sizes and shapes.
Once you have done that it is time to plant. Usually the taller stem plants will reside in the back of your aquarium, so let's start with those. We'll cover another species in the next article.
When getting ready to plant a stem plant, first cut with a scissors or knife an angled cut just above one of the healthy green nodes leaving as much of the plant as is possible.
When you plant it, push the lower part of the fresh cut plant roughly half to three quarters of the depth of the gravel. Allow enough space between plants to allow light to reach the lower leaves.
Stem plants are usually planted in their own random patterned group using five to eight stems. When the stem plant finally grows to the top of your aquarium, it will have rooted (and if your lucky or good, produced flowers) and sent out white roots in some species, from the nodes all the way up the plant.
To trim the stem plant you would cut at least eight inches of the top part of the plant, just above one of the nodes. Replant the cutting either by removing the old plant and replacing it with the cutting, or leave the old plant, add the new. In many cases the old plant in many cases will begin to grow new side shoots and create brand new plants. Before you know it, you'll have a bonus plant to trade at your Local Fish Store for possibly merchandise. Is your aquarium beginning to pay for itself a little?
A Word from Dr. Reich on the need for Plants in the Aquarium
The majority of freshwater community aquarium fish have shown definite preference for live aquarium plants in countless scientific tests over the decades.
In a well planted aquarium, fish can find shade from glaring light, privacy from things outside of the tank that startle them and a natural safety in times of stress.
Live plants allow different species startled by larger or aggressive tank mates to hide, or to evade the over eager potential breeding partner with some of the more aggressive species. With shoaling fish, plants give the group the currents and eddies they instinctively seek out in the wild.
When breeding many species, live aquarium plants are essential surfaces for the deposit and fertilization of eggs. Live aquarium plants have natural infusoria and other essential algae clinging to them or growing from them that feed the newborn fry of many species.
In short, live aquarium plants are essential in the creation of a natural or close to natural environment for most freshwater aquarium fish.