Tool
LED grow-light calculator for carnivorous plants
Most carnivorous plants need far more light than a room provides. Enter the size of your growing area and the plants on it; the calculator scales the per-square-foot figures from the International Carnivorous Plant Society's lighting page [1].
The figures the calculator scales
All figures are per square foot (30 × 30 cm) of growing area and come from the ICPS LED plant lighting page[1]. Watts are the fixture's actual power draw, not "equivalent" watts.
| Light level | White light (lux) | White LED | Blue/red plant LED | Hours a day |
|---|---|---|---|---|
| Intense | 15,000–25,000 | 30 W (2,000 lm) | 15 W | 12–16 |
| Moderate | 8,000–15,000 | 18 W (1,200 lm) | 9 W | not stated |
| Low | about 3,000 | indirect light; no wattage given | – | not stated |
Requirement by plant
| Plants | Light | Blue/red light only? |
|---|---|---|
| Venus flytrap (Dionaea) | Intense | Grows well under blue/red light |
| Sarracenia seedlings | Intense | Grow well under blue/red light |
| Cephalotus | Intense | Grows well under blue/red light |
| Heliamphora | Intense | Grows well under blue/red light |
| Drosera, most species | Intense | Use caution: some species are very sensitive to the blue/red ratio or total spectrum |
| Drosera adelae and D. prolifera | Moderate | Use caution: could be too much light |
| Drosera schizandra | Low | Blue/red light not recommended unless indirect |
| Nepenthes | Moderate | Grows well under blue/red light |
| Pinguicula, Mexican | Moderate | Use caution: could be too much light |
| Pinguicula, temperate | Moderate | Use caution |
| Utricularia | Moderate | Use caution: depends on species; strong light can encourage cyanobacteria and algae |
Where the numbers come from
The ICPS LED plant lighting page sorts carnivorous plants into three light levels and gives a target for each [1]:
- Intense light, about 15,000 to 25,000 lux of white light. Reaching 25,000 lux takes about 2,000 lumens, or 30 watts of white LED, per square foot of growing area; with blue/red plant LEDs about 15 watts per square foot works well. Flytraps, Cephalotus, Heliamphora, Sarracenia seedlings and most sundews are in this group.
- Moderate light, about 8,000 to 15,000 lux, which the page says can be reached with about 40% lower wattage. Nepenthes, the butterworts, the bladderworts and Drosera adelae are in this group.
- Low light, about 3,000 lux, best supplied as indirect light or spill-over from other lights. Drosera schizandra is the example the ICPS gives.
For intense-light plants the page says the lights should be on for 12 to 16 hours a day; it gives no separate figure for the other levels [1]. The calculator multiplies the per-square-foot figure by your area (one square foot is 30.48 × 30.48 cm). It reports actual watts drawn by the fixture, because the ICPS warns that “watt-equivalent” claims on packaging cannot be converted meaningfully [1].
The ICPS Venus flytrap guide gives a slightly different rule of thumb for display plants: about 25 W of white LED per 25 cm diameter growing area for about 14 hours a day, aiming for 15,000 to 25,000 lux [2]. Both figures point to the same light level; the calculator uses the lighting page because it covers every genus.
Limits of a wattage estimate
Watts measure power drawn, not light delivered to the leaves. LED efficiency differs between products, panels light the centre of a shelf much more than the edges, and LEDs dim with age; the ICPS notes they can be down to about 70% of their original brightness after 35,000 hours [1]. A lux meter is the practical check for white light. Blue/red light cannot be judged by eye or by an ordinary lux meter, and the ICPS suggests keeping some white light in the mix so you can see how the plants look [1].
Some plants are sensitive to the spectrum: the ICPS advises caution with blue/red-only light for many sundews and butterworts. The table on this page lists its notes for each group. For how light shows up in plant colour and shape, see weak color and floppy growth and the light guide.
Sources
- LED Plant Lighting. International Carnivorous Plant Society. Light requirement by genus; lux, lumens and watts per square foot; 12 to 16 hours a day. Accessed October 12, 2026.
- Growing Dionaea muscipula. International Carnivorous Plant Society. TDS under 90 ppm; dormancy only for plants facing freezing weather outdoors; LED wattage and lux; USDA-zone advice; soil choices. Accessed October 12, 2026.