Substrate
Substrate, next to lighting is the most important factor to healthy plants. Having the right substrate will make or break your plant keeping efforts. I will point out some of the pros and cons of the different substrate options. I will also point out the benefits of layering the substrates.
Types: Aquarium Gravel, Pea Gravel, Sand, Dirt/Mulch, Fluorite
Aquarium Gravel
Pros: Appealing color and look, wide variety available, beneficial to plants when bacteria is established.
Cons: Contributes very little natural metal content beneficial to plants. Many types are either too fine not allowing nutrients access to roots. Many types too large not allowing accumulation of nutrients.
Although appealing to the eye it is not the best choice for planted aquariums.
Pea Gravel
Pros: Is made up of many different size rocks and contains several key nutrients naturally. Cost is low and has a nice natural look.
Cons: No color variety available. Has to be cleaned before use. Rocks change color over time due to bacterial staining.
This is a cost effective way of growing plants without fertilizers. It has a natural appeal due to its rugged look.
Sand
Pros: Cost can be low. Gives a different look.
Cons: Limits plants types. Hard to keep looking nice. No natural nutrients. Nutrients are unable to reach roots.
Sand is not recommended for planted aquariums, but if you keep inhabitants that require sand there are specific plants available.
Dirt/Mulch
Pros: Very high nutrient levels. Cost is low. As close to wild substrate as you can get.
Cons: Very messy. Has to have substrate above it to keep water clear. Limited to non-burrowing fish. Compacts tightly over time.
Using dirt or cow manure mulch will give plants nutrients without the need for fertilizers. Only 100% mulch or dirt should be used (no additives). Best when used as a thin base layer.
Fluorite
Pros: Beneficial to plants.
Cons: Messy, expensive, no colors available
Though expensive it is beneficial to plants, but not necessary. Can never be fully cleaned.
Above I have given my personal opinions about experiences with the different types of substrate. I have found that to keep a self sustaining, planted show aquarium, layering the substrate has been the best method by far. Layering the substrate can give you the best look at an affordable price. Layering also gives the novice and experts alike the least margin of error for keeping plants healthy. There is no need for chemical fertilizers or CO2 to keep most plants.
