Grower's glossary
The terms you'll meet on our site and in our guides, in plain language. Tap an underlined word anywhere on the site to see its definition in place.
- 0–10 V dimming
- A standard dimming signal: a controller or timer sends 0 to 10 volts to set the light level, so lights can ramp up and down automatically.
- Channel fall
- The slight slope built into each NFT channel so the nutrient film flows to the return end. Too flat and water pools; too steep and roots dry out.Read the guide
- Clay pebbles (LECA)
- Lightweight expanded clay aggregate: fired clay balls that drain freely, don't break down, and can be washed and reused.
- Coco (coco coir)
- Fibre from coconut husks, used as a soil-free growing medium. It holds water and air well and is renewable.
- Dripper (emitter)
- A small fitting that releases water at a set rate, such as 4 L an hour. Pressure-compensating drippers give every plant the same flow along the whole line.
- Dutch bucket
- A square bucket with a drain near the base, holding one or two plants in a medium and fed by a drip line. Made for big fruiting crops such as tomatoes, peppers and cucumbers.
- EC (electrical conductivity)
- How much nutrient is dissolved in the water, read with an EC meter. Higher EC is a stronger feed: seedlings want it low, fruiting plants higher.
- Full spectrum
- Light across the whole visible range rather than only red and blue, so it looks close to white and plants get balanced light at every stage.
- Hydroponics
- Growing without soil. Roots take water and nutrients straight from a solution, either in channels or in an inert medium such as coco or clay pebbles.Read the guide
- IP65
- Dust-tight and protected against water jets from any direction, so the fixture copes with humid rooms and can be hosed down.
- Microgreens
- Vegetable and herb seedlings harvested days after sprouting, while they're small, tender and full of flavour.
- Net pot
- A slotted plastic cup that holds a plant in the channel, so its roots grow through into the nutrient flow.
- NFT (nutrient film technique)
- A thin film of nutrient solution runs down a gently sloped channel past the roots and back to the reservoir, so roots get water, food and air at the same time.Read the guide
- PAR (photosynthetically active radiation)
- The band of light, from about 400 to 700 nm, that plants use for photosynthesis. A PAR sensor shows how much usable light actually reaches your plants.
- Perlite
- Expanded volcanic glass: light white granules mixed into a medium to add air and drainage.
- pH
- How acidic or alkaline the nutrient solution is. Most hydroponic crops take up nutrients best between about pH 5.5 and 6.5.
- PPF (photosynthetic photon flux)
- The total light a fixture produces that plants can use for photosynthesis, in µmol per second. It measures output for plants, not brightness to the eye.
- VPD (vapour pressure deficit)
- How strongly the air draws moisture out of the leaves, worked out from temperature and humidity together. Too low and plants stop drinking; too high and they stress.
- µmol/J (efficacy)
- How much plant-usable light a fixture makes per joule of electricity. Higher means more light for the same power bill.