Do Carnivorous Plants Need Watering? Pot Watering and Wet/Dry Assessment Methods

Many beginners think carnivorous plants are rather special and are unsure whether they should water them. In fact, potted carnivorous plants cannot do without water either, and watering them calls for more care than ordinary potted plants. The core principle comes down to eight words: check regularly, water on demand.

Watering frequency depends on conditions, so do not water mechanically on a schedule

How often you water carnivorous plants depends mainly on factors such as how enclosed the environment is, temperature, pot size, plant size and the watering method used. Watering on a fixed schedule does not suit plant growth, because under different conditions water is used up at different rates. The sensible approach is to check the potting soil often and water only when the plant needs it. A word of warning: many flowers actually drown from overwatering. When there is too much water and the soil stays waterlogged for a long time, the roots begin to rot, the leaves turn yellow, and the plant will soon die if nothing is done. So it is better to observe frequently than to water blindly and generously.

First work out whether a species likes it dry or moist

Carnivorous plants fall into those that like moisture and those that like dryness. Most pitcher plants (Nepenthes) should have potting soil on the drier side, with a loose, airy substrate that does not hold standing water; Venus flytraps, most sundews (Drosera), bladderworts (Utricularia) and the like like moisture, so their potting soil should stay fairly damp, and the pot can even be stood directly in a shallow tray of water; pitcher plants (Sarracenia) are undemanding and can cope with either drier or wetter conditions.

To judge whether the potting soil is dry or wet, visual inspection is enough: when the soil is damp it looks dark grey; when it is very wet or waterlogged, the surface shows flecks of white shine from the water; when the soil is on the dry side it turns dull grey and loses its sheen; when it is bone dry it looks greyish white. If you are not sure, you can also push a finger about 3 cm into the soil to feel it, or water thoroughly and then weigh the pot in your hand; if the weight later drops noticeably, that means it is short of water.

Three watering methods, each with its own use

When you find the potting soil is on the dry side, water it. The three commonly used methods are spraying, pouring and soaking.

Spraying means using a spray bottle to wet the leaves and the potting soil. It suits giving plants a weekly leaf clean, it suits supplying water when propagating pitcher plants from leaf cuttings, and it can also be used for the routine watering of most carnivorous plants. The exception is carnivorous plants with sticky mucus, such as sundews and butterworts (Pinguicula): frequent spraying washes the mucus away, causing the mucus-secreting glands to wither and die, so the "dewdrops" become hard to form.

Pouring means watering directly with a watering can. It suits large carnivorous plants such as pitcher plants (Nepenthes) and pitcher plants (Sarracenia).

Soaking means pouring water into the saucer beneath the pot and letting capillary action keep the potting soil moist. This is the most convenient way to water, as one go keeps the soil supplied for a longer time. It is especially suitable for moisture-loving carnivorous plants, and it is also the best method for sticky varieties such as sundews and butterworts. When growing dry-loving species, you can adjust the potting soil mix, adding more coarse, free-draining, airy substrate, and still use the soaking method.

Water quality matters too

The water we drink day to day is soft water, and water whose hardness has been lowered by boiling can also be used to water plants; rainwater, river water and well water are all fairly suitable. Using tap water directly over the long term easily makes the potting soil alkaline and compacted, and turns the plant's leaves yellow. Tap water is best left in a container for 2-3 days before use, which removes the fluorine and chlorine compounds in it.

In short, there is no fixed timetable for watering potted carnivorous plants. Work out each species' preference for dry or moist conditions, check often and water on demand, and combine that with a suitable watering method, and your pitcher plants and Venus flytraps will grow vigorously and their traps will look even more beautiful.