Why it matters at the root
Rhizosphere: Chlorine in irrigation water kills some of the useful microbes living around roots.
Living soil: Microbial teas, compost and organic mixes lose part of their benefit if the water is still chlorinated.
Hydro still cares: Even mineral systems do better when beneficial life is not being stripped every watering.
Chlorine versus chloramine
Old chlorine
The familiar-smelling chlorine used in older systems leaves if tap water sits for a day or two
Modern default
Most utilities now use chloramine, which does not evaporate on the counter
Do not assume
If the water no longer smells like a pool, it may still carry chloramine
How growers strip it
Aquarium remover
Fish keepers use additives that neutralize chlorine and the ammonia that chloramine can release
Ascorbic acid
About one gram of vitamin C per 75 gallons (285 L) of water is Rosenthal's plant-safe chloramine option
Confirm locally
Ask the utility which disinfectant they use before you pick a standing-bucket method
Practical habit
Treat the tank
Neutralize a reservoir or watering can before nutrients go in
Living teas
Never brew compost tea with untreated chlorinated tap if you want the biology to survive
After RO
Reverse osmosis also removes disinfectants, but the blend water you add back may still need treatment