Humidifiers & Dehumidifiers

Humidifiers and dehumidifiers for grow tent VPD

Humidity swings more than most growers expect between stages, and getting it wrong in either direction costs you — too dry and cuttings won't root, too wet in flower and you're growing botrytis instead of buds. Target roughly 70–80% RH for seedlings and cuttings, 50–70% through veg, dropping to 40–50% in flower and 35–45% late flower, full detail in our grow tent setup guide.

The Pure Factory 8L humidifier (£44.95) suits a single tent or propagation space that's running dry. Step up to the G.A.S SonicAir 10L (£84.95) or 23L Sonic Air (£164.95) for a bigger room, and the G.A.S SonicAir Pro (£299.95, down from £349.95) if you're running a full grow room that needs sustained output rather than topping up every day. Going the other way, disposable options like the Dry Bag (£6.50) and Dry Pot (£7.50) pull excess moisture out of a small tent without any running cost or power draw.

The mould connection

Humidity above 55% in flower is the mould danger zone, especially once buds start swelling and airflow through the canopy drops. A dehumidifier tackles the air directly; a circulation fan moving air through the canopy tackles the still, damp pockets where botrytis actually starts. See our humidity control range and mould prevention products if you've had issues before. Free UK delivery over £50, or call 020 3488 0419 for help sizing a unit to your room.