Dwarf Hairgrass (Eleocharis parvula or Eleocharis acicularis) is an aquatic plant prized for forming a dense, vibrant green carpet across the aquarium floor. This lawn-like effect creates a beautiful foreground aesthetic. Achieving a lush, full carpet requires specific environmental conditions and consistent care tailored to the plant’s unique growth habit. This guide outlines the steps necessary for successful dwarf hairgrass cultivation.
Substrate Preparation and Planting Techniques
The foundation for a successful carpet lies in the substrate, which must provide both anchoring and nutrition. Nutrient-rich aquatic soils (aquasoils) are the preferred base as they release essential minerals directly to the roots. Inert substrates like sand or fine gravel must be supplemented with organic material or specialized nutrient amendments.
Before planting, prepare the dwarf hairgrass by separating larger clumps into smaller, manageable portions. Divide each cluster into tiny plugs, ideally consisting of only a few blades and their attached roots. This separation allows the plant sufficient space to send out its stolons, which are the primary means of horizontal spreading.
Planting is best accomplished using specialized aquascaping tweezers to gently insert the root system deep into the substrate. Place these small plugs in a grid pattern, spacing them approximately one to two inches apart. A denser initial planting reduces the time required for the runners to connect and form a seamless mat.
Essential Environmental Conditions
Achieving a dense carpet requires high-intensity lighting, as the plant needs significant energy to produce runners. A Photosynthetically Active Radiation (PAR) reading of 50 to 70 \(\mu\)mol/\(\text{m}^2/\text{s}\) at the substrate level is necessary for robust, horizontal growth, with an optimal photoperiod of eight to ten hours per day.
The availability of dissolved carbon dioxide (\(\text{CO}_2\)) is the most important factor for rapid carpeting growth. While dwarf hairgrass survives without \(\text{CO}_2\) injection, it will spread slowly and remain patchy. Injecting \(\text{CO}_2\) to maintain 25 to 35 parts per million (ppm) significantly accelerates growth and runner production.
Water temperature should be maintained between 72°F and 78°F (22°C to 25°C) to support a high metabolic rate. Adequate water movement across the substrate helps distribute nutrients and prevents the accumulation of waste material within the dense carpet.
Nutritional Requirements and Fertilization Schedule
Dwarf hairgrass is primarily a root feeder, absorbing nutrients directly from the substrate. This necessitates the regular application of root tabs inserted deep beneath the plant plugs. Root tabs should be placed approximately every six inches and replaced every two to three months as nutrients are depleted.
Liquid fertilization is necessary to supply nutrients to new growth and the water column, supporting overall plant health. A balanced dose of macronutrients (N, P, K) and essential trace elements like iron and magnesium should be added regularly. Weekly dosing of a comprehensive liquid fertilizer ensures that no single nutrient becomes a limiting factor for growth.
Consistent nutrient availability is important in high-light and high-\(\text{CO}_2\) environments, as the plant’s accelerated metabolism consumes resources quickly. Regularly monitoring for signs of deficiency, such as yellowing tips or stunted growth, allows for immediate adjustment of the fertilization schedule.
Maintaining a Dense Hairgrass Carpet
Once the runners have begun to intertwine, regular trimming is necessary to maintain the carpet’s dense appearance. Aggressive trimming forces the plant to focus energy on lateral growth. Using sharp, curved scissors, cut the blades down to one or two inches tall, encouraging the root network to send out more side shoots.
Trimming should be performed every two to four weeks, depending on the growth rate, and clippings must be removed to prevent decay and nutrient spikes. Allowing the grass to grow too tall causes the lower portions to become shaded and die off, resulting in a patchy, brown underlayer.
A dense carpet can accumulate detritus and debris, leading to localized algae growth. Regular, gentle surface cleaning prevents the buildup of organic matter. Periodic vacuuming around the edges prevents substrate compaction, which hinders runner spread and restricts oxygen flow to the roots.