Carpeting Aquarium Plants
Carpeting plants can seem daunting for new aquascapers. As I contemplated entering the planted aquarium hobby, I was fairly confident that I’d have success growing easy stem plants, but I was much less sure of my ability to grow carpeting plants: the smaller, “ground cover” plants that form a dense mat over the foreground of a tank. As it turns out, there was little need for me to worry.
Part of the misconception that achieving a dense carpet is best left to the pros ultimately boils down to poor plant choice. In fact, with the right plant species, a carpet can even be achieved without CO2. Unfortunately, many new aquascapers are often unaware of these easier species, and choose much more difficult, temperamental plants such as HC (Hemianthus callitrichoides 'Cuba') or Glossostigma elatinoides. While beautiful, these species are much more reliant on diffused carbon dioxide and consistent, stable water conditions and parameters.
Better carpeting plants for beginners (and just as beautiful) would be the Marsilea species (hirsuta or crenata are good choices) or Micranthemum 'Monte Carlo' (Micranthemum Tweediei). The former are tiny freshwater ferns that resemble little individual leaflets (or occasionally, 4-leaf clovers). The latter, my personal favorite, is very similar to HC, but has slightly bigger leaves and a much more robust growth habit. Both will grow extremely quickly with CO2, and will still form a carpet (albeit more slowly) even without CO2. In my experience, Monte Carlo will have smaller leaves when grown in a low-tech (non-CO2) environment.
Falling somewhere in the mid-range in terms of difficulty are the Eleocharis species (dwarf hairgrasses). Resembling a fine-bladed, grassy lawn, a full dwarf hairgrass carpet is both satisfying and somewhat difficult to achieve. No one will have trouble growing the plant, but getting it to form a dense mat is another story.
Finally, I’d like to offer some tips for growing a successful carpet. Much like many other endeavors in life, everything will be easier if you start out with a good foundation: aquasoil. A good, nutrient rich substrate like Ultum Nature Systems Contrasoil will provide the perfect medium for a carpet to grow and spread in. I recommend moistening the soil before planting, and using thin steel pincettes to push small groupings of the plants relatively deep into the soil at regular intervals, with just a bit of the plant poking out from the substrate. This way, they will stay rooted when you fill the tank with water, and will form an even carpet as they spread.
When choosing plants, I’d recommend going with tissue culture specimens. These small, sterile cups of baby plants are ideal for planting in the method described above, and can be used without fear of introducing snails, filamentous algae, or other annoying pests into your tank. Buceplant has a great selection of tissue culture plants available on their site.
Most carpeting plants like relatively soft, acidic water. I keep my tanks at a pH around 6.8, and keep the water hardness relatively low. I also inject the water with pressurized CO2, which provides the plants with a readily available source of carbon, from which they can build their tissues and spread. A great light fixture will help the plants grow close to the substrate (instead of developing an upright habit). I recommend Twinstar’s RGB LED lights. Regular maintenance (water changes, fertilization, etc) will help your carpet thrive. And don’t be afraid to trim pretty aggressively- frequent trimming of carpeting plants (especially faster growing species) will encourage lateral growth. There’s really no need to trim slow growing species (*like Marsilea species) unless it’s sending runners into places you’d rather it stay out of.
Hopefully this brief guide will help you become more confident when dealing with carpeting plants. Don’t be afraid to explore other species that I didn’t mention. Happy scaping!