Help & glossary
The words on plant pages, explained, and how contributing works.
Glossary · 17 terms
KH (carbonate hardness)
How well water resists pH changes. Low KH means pH swings more easily. Measured in °dH.
GH (general hardness)
The amount of calcium and magnesium in the water — “soft” or “hard” water. Measured in °dH.
pH
How acidic (below 7) or alkaline (above 7) the water is. Most plants are happy between 6 and 7.5.
CO₂
Carbon dioxide plants use to grow. “Helps” means extra CO₂ speeds growth; “Required” means it struggles without it.
Submersed
Growing fully underwater — how plants grow in your tank.
Emersed
Growing with leaves above water. Many farms grow plants this way, so new plants may change shape once underwater.
In vitro
Grown in a sterile lab cup on gel. Pest- and algae-free.
Rhizome
A thick, creeping stem that leaves grow from. Tie it to wood or rock — don’t bury it.
Runner
A side shoot that grows along the ground and makes a new plant at its tip. Cut it off once the young plant has roots.
Cultivar
A named form selected by growers, written in quotes: ‘Colorata’.
Synonym
An older or alternative scientific name for the same plant. Search finds a plant under any of them.
Trade name
The name on the shop label, like “Monte Carlo” or “HC Cuba”. Often not the scientific name.
Melt
When a plant sheds leaves after a change. Common with Cryptocoryne; it usually regrows.
Carpeting plant
A low plant that spreads to cover the foreground like a lawn.
Stem plant
A plant with leaves along an upright stem. Trim and replant the tops.
Substrate
The gravel, sand or soil on the bottom of the tank. Some plants feed from it, others don’t care.
Low-tech, high-tech
Low-tech: no added CO₂ and modest light. High-tech: added CO₂ and strong light, faster growth.