Sundew Care Guide (Drosera)
Sundews catch prey with glandular tentacles that hold a bead of sticky mucilage at the tip. In good light those beads glitter, and the plant works constantly, which makes sundews the most effective fungus gnat control most growers will ever own.
This guide covers Drosera tokaiensis, the Japanese sundew we grow and sell, along with the subtropical species that share its care. Temperate species differ on one important point, covered under Temperature below.
Light
Sundews want as much light as you can give them. Light drives both dew production and colour.
- Outdoor light: full sun, or a minimum of 4–6 hours of direct sun
- Indoor light: a strong grow light within roughly 6–12 inches of the plant
A sundew grown too dim will still open new leaves, but the tentacles stay short, the dew is sparse or absent, and the plant stays green instead of colouring up. Sparse dew is almost always a light problem before it is a humidity problem.
Water
Sundews are as mineral-sensitive as Venus flytraps. Tap water will kill them, usually over weeks rather than days, as dissolved salts accumulate in the media.
Use only:
- Rainwater
- Distilled water
- Reverse osmosis (RO) water
Stand the pot in a tray with about ½–1 inch of water and keep it there year round. Sundews are bog plants and do not want to dry out between waterings.
Humidity
Sundews are more forgiving of household humidity than their reputation suggests, provided the roots stay wet.
- Ideal humidity: 50–70%
- Tolerated: 40–50% household humidity, with dew production somewhat reduced
If a plant arrives dewless after shipping, that is normal. Give it bright light and a wet tray, and the dew usually returns within a few days.
Temperature
Drosera tokaiensis is subtropical and grows year round. It does not require a winter dormancy, which is the main reason it is easier than a Venus flytrap.
- Day: 70–85°F (21–29°C)
- Night: 50–70°F (10–21°C)
It tolerates brief dips near freezing and will simply slow down in winter. Temperate sundews such as D. rotundifolia, D. filiformis and D. intermedia are a different case: those form a winter resting bud called a hibernaculum and do need 3–4 months of cold, the same as a flytrap.
Potting Media
Nutrient-free and acidic, exactly as for other carnivorous plants.
- 1:1 peat moss and perlite
- 1:1 peat moss and washed silica sand
- Long-fibre sphagnum moss for larger pots
Never use standard potting soil, compost, or anything containing fertiliser. Never fertilise the soil.
Feeding
A sundew in good light feeds itself. Indoors it will work through fungus gnats, fruit flies and other small insects without any help.
There is no need to feed by hand. If you want to, a single small insect or a few grains of rehydrated freeze-dried bloodworm placed on the dew is plenty; avoid anything large enough to rot on the leaf.
Propagation
Drosera tokaiensis is self-fertile and sets seed readily. Left alone in a tray, it will seed itself into neighbouring pots, which is why growers often describe it as a friendly weed. Seed germinates on the surface of damp media in bright light with no cold stratification required.
Common Mistakes
Avoid:
- Using tap or bottled mineral water
- Growing in standard potting soil
- Low light, then blaming humidity for the missing dew
- Letting the tray run dry
- Fertilising the media
- Touching the leaves repeatedly, which wastes mucilage
Given pure water, a wet tray and strong light, sundews are among the most forgiving carnivorous plants you can grow, and they earn their keep the first time a fungus gnat lands on one.
Other care guides: Venus Flytrap · Nepenthes · Monstera · All guides
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