Grow lights for hydroponics: choosing coverage before wattage
Choose a light by usable coverage at the plant canopy, not by a model name or exaggerated equivalent wattage. Leafy crops need less intensity and height than fruiting tomatoes.
Complete topic hub
Lights and power
Size lights by canopy coverage, calculate UK running costs and plan safely for wet systems near mains power.
6 practical guides
Choose your next question
Grow light running costs: calculate the real UK cost
Multiply the light’s measured watts by hours used and your electricity unit rate. Standing charges are not added because you pay them whether or not the light is on.
Grow light distance: setting height by plant response
Start with the manufacturer’s hanging guidance for the crop and footprint, then watch the whole canopy. Stretching suggests too little usable light; bleaching, curling or heat stress can mean too much or too close.
Hydroponic light schedules: timers, darkness and seasons
Use a timer to give plants a consistent daily light period and a dark period. The right duration depends on crop and intensity, so more hours cannot always compensate for a weak light.
Hydroponics electricity use: pumps, lights and realistic totals
The grow light usually dominates a small indoor system’s electricity use; pumps are smaller but may run continuously. Add each device’s watts multiplied by operating hours to get the total.
Hydroponics during a power cut: protecting roots
Short light interruptions are usually less urgent than loss of root-zone aeration or circulation. In DWC, agitate the solution by hand; in NFT or aeroponics, keep roots damp while power is off.