Drosera capensis Care Guide: Cape Sundew Water, Light & Propagation

Drosera capensis Care at a Glance

• Light: High intensity, 150-250 PPFD, for 12-16 hours daily.
• Substrate: 50% unfertilized Canadian sphagnum peat and 50% coarse washed silica sand or perlite.
• Water: RO, distilled or rain water, ideally under 20 ppm TDS and never above 50 ppm, in a constant 1-2 cm tray.
• Temperature: 15-28°C (59-82°F), with 50-80% humidity and gentle airflow.
• Dormancy: None. It grows all year.
• Propagation: seed, leaf cuttings and root cuttings.

What Is Drosera capensis?

Drosera capensis, the Cape sundew, is a fast-growing carnivorous plant in the family Droseraceae. It comes from the Cape Province of South Africa, where it grows in fynbos and along stream seepages. Its long, narrow leaves are covered in tentacles tipped with glistening droplets of sticky mucilage. Insects stick to the dew, and the leaf slowly curls around them as nearby tentacles bend inwards, a movement called thigmotropism, and digests them. It is one of the easiest sundews to grow and a good first carnivorous plant. For a companion with a different winter pattern, see Pinguicula moranensis.

Light

Strong light is the key to a good Cape sundew. Aim for 150-250 PPFD for 12-16 hours daily. A bright south or east window can work, but most indoor growers do better with an LED grow light 15-30 cm above the plant. Strong light turns the tentacles red through anthocyanin pigments and drives heavy dew production. Plants in weak light turn green, grow floppy and make little dew.

Water: The Continuous Tray Method

Stand the pot in a tray holding 1-2 cm of RO, distilled or rain water at all times. Unlike many carnivorous plants, Drosera capensis tolerates constant wetness and does not need a drier season. Use water under 50 ppm TDS, and aim for under 20 ppm. Minerals in tap water build up in the peat as water evaporates, burn the roots and tentacle tips and dry up the dew. Test the tray with a TDS pen, and use the carnivorous water TDS calculator to check blends and estimate how fast minerals accumulate in your pot. Flush the pot from the top with pure water every month or two, and never use fertilizer.

Substrate

Use a mix of 50% unfertilized Canadian sphagnum peat moss and 50% coarse washed silica sand or perlite by volume. This holds moisture but stays open enough for roots to breathe. Never use potting soil, fertilizer, or sand that contains lime or shell. Rinse sand and perlite in RO water before mixing. The carnivorous plant substrate guide covers other mixes and what to avoid.

Temperature, Humidity and Airflow

The plant grows best at 15-28°C and tolerates cooler spells down to about 5°C. Hard frost kills the leaves, but the roots can resprout from the base. Moderate humidity of 50-80% is enough, and gentle air circulation helps prevent mold on dead leaves. In an enclosed display, ventilate so the surface does not stay saturated. The carnivorous plant terrarium build guide explains how to ventilate a terrarium and group plants with similar needs.

No Dormancy Needed

Drosera capensis is a subtropical perennial and does not need a cold winter rest. In winter it may slow down and make fewer leaves, but it should stay green and sticky in bright light. This is different from Venus flytraps, Sarracenia and temperate sundews, which need cold dormancy. The dormancy requirements guide explains which plants rest and which do not. Mexican butterworts also differ, because they need a near-dry winter substrate, as described in the Pinguicula rock setup guide.

Trapping and Feeding

The Cape sundew works as living flypaper for fungus gnats, fruit flies and other small flies. Prey sticks to the dew, and the leaf curls around it within hours. A plant in a room with a few gnats or flies usually feeds itself. If prey is scarce, rehydrate a few dried bloodworms in a drop of RO water and place a small piece on one or two leaves. Feed only a leaf or two at a time, no more than once every week or two, and never feed the substrate or tray.

The plant catches only adult insects, so it does not kill fungus gnat larvae in the soil of other houseplants. Combine it with BTI and a dry-down cycle as described in carnivorous plants for fungus gnats. Place the plant within 30-60 cm of the infested pots, and let leaves covered in carcasses wither naturally.

Flowering and Self-Seeding

Healthy plants send up tall stalks with clusters of pink to purple flowers from spring through summer, and often flower repeatedly in good light. Each flower produces plenty of fine black seed. In a bog terrarium or crowded tray, seedlings can pop up everywhere. To prevent this, cut the flower stalks at the base before the seed ripens. If you want more plants, let one stalk dry and collect the seed. Do not release the plant outdoors, because it has naturalised in some regions.

Propagation

The second reference table above compares the three methods.

From Seed

1. Collect ripe black seed from dried flower heads.
2. Sprinkle it on the surface of damp peat and sand mix. Do not cover it.
3. Keep the pot in a tray of RO water, in bright light and high humidity.
4. Seed usually sprouts in one to three weeks. Thin crowded seedlings after a couple of months.

From Leaf Cuttings

1. Cut or pull a healthy, young leaf from the base.
2. Lay it on damp peat and sand mix, or float it in a shallow dish of RO water.
3. Keep it bright, warm and undisturbed.
4. Plantlets form at the base or along the leaf in two to six weeks.

From Root Cuttings

1. Lift the plant in spring and wash the roots in RO water.
2. Cut thick root pieces about 2-4 cm long.
3. Lay them flat on the surface of damp medium and keep them humid and bright.
4. New shoots appear in three to six weeks. Roots left in the old pot often resprout on their own.

Repotting and Maintenance

• Weekly: check the tray, remove dead black leaves and look for algae, mold or white crust.
• Monthly: check the TDS of the tray and flush the pot with RO water.
• Every 1-2 years: repot in fresh peat and sand mix in spring, and divide crowded clumps.

Troubleshooting Summary

Related Resources

Plan an enclosure with the carnivorous plant terrarium build guide, choose a medium with the carnivorous plant substrate guide, grow a butterwort on rock with the Pinguicula rock setup guide, compare winter care in the dormancy requirements guide, use sundews for pest control with carnivorous plants for fungus gnats, check your water with the carnivorous water TDS calculator, and meet companions in the profiles for Pinguicula moranensis and Nepenthes ventrata.