Carnivorous plants, grown from the sources
Profiles, care guides and fixes for Venus flytraps, pitcher plants, sundews and butterworts. Every number links to the growing guide, flora or Red List assessment it comes from, so you can check it yourself.
The questions growers ask most
- Why Venus flytrap traps turn black, and when to worry
Some blackening is normal: each Venus flytrap leaf lasts only a few months, and a healthy plant keeps making new ones as the old ones die.
- Venus flytrap traps not closing: causes and checks
A trap needs two touches of its trigger hairs within about 15 to 30 seconds, and once it has closed it takes roughly 16 to 44 hours to reopen, so a trap that ignores one poke or stays shut for a day is behaving normally.
- Sundew not making dew: light, humidity, water and dormancy
Check light first: most sundews need intense light, and experiments show that shaded sundews make less sticky leaves.
- Sarracenia pitchers turning brown: normal aging or trouble
Often it is normal: Sarracenia go dormant in autumn and their pitchers turn brown, and older pitchers die off during the season as well.
- Nepenthes not making pitchers: light, humidity and age
Light and humidity are the usual limits.
- Mineral burn from tap water, salty soil and fertilizer
Carnivorous plants come from nutrient-poor habitats and can be killed by water with moderate or high dissolved solids, by fertilizer and by ordinary potting mix.
The plates
This guide covers nine genera. Each has a page with its species, the conditions they need and the sources behind them.
Care in brief
Carnivorous plants differ from houseplants in four ways that matter: they need mineral-poor water, a lot of light, a soil with no fertilizer, and, for many of them, a cold winter.
- Water for carnivorous plants: TDS limits, rainwater and the tray method
Use rain, distilled or reverse-osmosis water, or tap water only if its total dissolved solids (TDS) are low: the ICPS Venus flytrap guide puts the line at 90 ppm and its seed guide at 80 ppm.
- Light for carnivorous plants: sun, windowsills and LED grow lights
Venus flytraps, Sarracenia seedlings, most sundews, Cephalotus and Heliamphora need intense light: full sun outdoors, or about 15,000 to 25,000 lux of white LED light indoors for 12 to 16 hours a day.
- Carnivorous plant soil: peat, sand, perlite and sphagnum mixes by genus
The ICPS default for most carnivorous plants is an equal mix of unfertilized sphagnum peat and coarse silica sand with grains of about 1.5 to 2 mm.
- Winter dormancy: which carnivorous plants need it and how to provide it
Sarracenia expect a cool winter rest, and cold temperate sundews and butterworts need real winter cold to survive long term.
- Feeding carnivorous plants, and why fertilizer is risky
Plants that catch insects on their own need no help, but a plant that is not catching prey should be fed in the traps with live insects or rehydrated dried bloodworms.
- Growing carnivorous plants indoors all year
Indoors, light decides almost everything.
Tools
- Troubleshooter
Pick what you see, such as black traps, brown pitchers or dry sundews, and get the likely causes, what to check, and the guide for each.
- Water checker
Enter a TDS or EC reading and see whether your water is under the limits the International Carnivorous Plant Society publishes for plants and seeds.
- Dormancy planner
Find out whether your flytrap, pitcher plant, sundew or butterwort needs a winter rest, what it looks like, and what to do each season where you live.
- Soil mix calculator
Enter your pot size and choose a plant; get the litres of peat, sand, perlite or sphagnum for a mix published by the International Carnivorous Plant Society.
- Grow-light calculator
Work out how many watts of white or blue/red LED light a shelf of flytraps, sundews, butterworts or Nepenthes needs, from published ICPS figures.
Propagation
- Cold stratification for Sarracenia, Darlingtonia and temperate sundew seed
- Dividing a crowded Venus flytrap and replanting the pieces
- Dividing Sarracenia: splitting a crowded pitcher plant clump
- Mexican butterwort leaf pullings: timing, removal and rooting
- Nepenthes stem cuttings: from climbing vines and rosettes
- Propagating Cephalotus: crown divisions, stem cuttings and leaf pullings
- Pygmy sundew gemmae: collecting, sowing and mailing them
- Sowing carnivorous plant seeds: surface sowing, step by step
- Sundew leaf cuttings in water or on peat
- Venus flytrap leaf pullings: new plants from old leaf bases
How this guide is made
Pages are drafted from primary sources: the International Carnivorous Plant Society's growing guides, the Carnivorous Plant Newsletter, Kew's World Checklist of Vascular Plants, the IUCN Red List, floras, government agencies and peer-reviewed papers. Each page lists its sources with the date they were read. Nothing here is based on claimed personal trials. Read the full method.