Here are straightforward answers to the questions we hear most often from people buying their first indoor grow light.
What should I look for when buying a grow light?
Prioritize four things: spectrum (does it suit your plant type and growth stage), PPFD at your actual hanging height, effective coverage area at that intensity, and heat output relative to your space size. Wattage and marketing claims matter far less than these four measurable factors.
How many watts do I need for indoor growing?
There’s no fixed answer, since wattage alone doesn’t tell you how much usable light a fixture produces. A better approach is to check the PPF per watt rating and the PPFD delivered at your intended hanging height for your specific tent or shelf size, rather than shopping by wattage alone.
What PPFD do my plants need?
Leafy greens and herbs generally do well around 200 to 400 PPFD, while fruiting plants like tomatoes and peppers typically need 600 to 900 PPFD during flowering. Seedlings and clones need much less, often under 200 PPFD, since excess intensity at that stage can cause stress.
Do I need a full-spectrum light or just red and blue?
Full-spectrum lights that include green, far-red, and a touch of UV alongside red and blue tend to support healthier, more complete growth than narrow red-and-blue-only fixtures. Full spectrum also removes the need to switch fixtures between vegetative and flowering stages.
How close should I hang my grow light?
Hanging height depends on the fixture’s intensity and your plant’s light tolerance. Check the manufacturer’s PPFD-at-distance chart if one is provided, and start further away than you think you need to, since it’s easier to lower a light gradually than to recover from light-stressed or bleached leaves.
How many hours a day should I run my grow light?
Most vegetative growth stages do well with 16 to 18 hours of light per day, while flowering stages for photoperiod plants typically shift to a 12-hour light and 12-hour dark cycle. Herbs and leafy greens are more flexible and generally do fine anywhere from 12 to 16 hours.
Does grow light heat matter if I have a small tent?
Yes, heat matters more in small or enclosed spaces because there’s less air volume to dissipate it. In a small tent, a lower-heat LED fixture will generally require less supplemental ventilation than an HID or older metal halide setup of similar output.
How do I know if a grow light is energy efficient?
Ask for the PPF per watt figure rather than relying on wattage or price. Higher PPF per watt means you’re getting more usable light for every dollar of electricity, which compounds significantly over a full growing season of daily use.
Have your answers? Shop Nano Grow Light fixtures and put this checklist to work in your own space.