The short answer
The dry start method (DSM) means growing your carpeting plants emersed — above the waterline, in a humid, sealed tank — before you flood it with water. You plant into damp aquasoil, cover the tank to trap humidity, and let the carpet root and spread in air for several weeks. Only once it’s established do you fill the tank.
Why aquascapers use it
Growing emersed sidesteps the two hardest parts of establishing a carpet underwater:
- No algae battle. Algae need water to take hold, so a dry-started carpet builds up strength before algae ever get a chance.
- Faster, tougher rooting. Carpet plants grow readily in humid air and anchor firmly, so they don’t float loose when you flood.
- No CO2 needed yet. Emersed plants take CO2 straight from the air, so you get carpet growth before committing to a gas system.
How it works, step by step
- Set up the substrate — a nutrient-rich aquasoil, sloped and dampened (not flooded).
- Plant the carpet — press small portions of Monte Carlo, dwarf hairgrass or similar into the wet soil.
- Mist and seal — spray with dechlorinated water and cover the tank with cling film or a lid to hold humidity.
- Light and wait — give it aquarium light on a normal cycle, mist daily, and vent briefly if mould appears.
- Flood — after four to eight weeks, once the carpet has knitted and rooted, slowly fill the tank.
Tip: keep humidity high but not stagnant. A quick daily airing prevents mould while the sealed cover stops the carpet drying out. Use dechlorinated water for misting.
After you flood
Once submerged, some emersed leaves may melt and be replaced by underwater growth — that’s normal. At this stage CO2 and fertiliser really pay off. See CO2 for beginners, and read how to plant a carpet and our aquascaping for beginners guide for the full workflow. For the right base layer, browse the substrate hub.