Guttation in plants: what causes water droplets on indoor plant leaves?

Have you noticed a uniform distribution of water droplets on the leaves of your houseplants? This is a natural phenomenon in the wild and can happen to indoor plants as well, and is known as guttation.

Guttation is a natural process that frequently occurs on plants outdoors. There are also some indoor plants with which guttation is quite commonly associated. These include arrow leaf plants and elephant ears, both of which belong to the genus Alocasia, as well as pothos (Epipremnum sp.). Read on to find out why guttation occurs and what the liquid actually is.

What is guttation in plants?

Guttation in plants is the name for the process whereby liquid is exuded through special glands called hydathodes. Hydathodes are located in the tips of leaves or some stems. Guttation occurs at night or in the early morning when soil moisture levels and relative humidity are high. During these times, transpiration rates are lower than in the day, when the plants are actively growing. Yet, at the same time, the roots are still taking up water, causing a build-up of pressure in the plants. It is this pressure that forces sap out of the hydathode glands. The sap exuded during guttation is a mixture of water, sugars, water soluble minerals and other soluble compounds circulating through the plant. Therefore, when the sun comes out and water evaporates, a white, crusty deposit remains. Here is a list of several typical houseplants with which guttation can be a common occurrence:

• Philodendrons (Philodendron sp.)
• Split leaf philodendrons or Swiss cheese plant (Monstera sp.)
• ZZ plant (Zamioculcas zamiifolia)
• Arrow leaf plants and elephant ears (Alocasia sp.)
• Orchids (Orchidaceae)
• Dieffenbachia or dumb cane (Dieffenbachia sp.)

Tip: outdoors and in nature, guttation occurs on many plants including fuchsias (Fuchsia sp.), cultivated strawberries (Fragaria x ananassa), wild strawberries (Fragaria sp.), the lady’s mantle (Alchemilla sp.), nasturtium (Tropaeolum sp.), and horsetail (Equisetum sp.), just to name a few.

Can you stop guttation?

The best way to reduce guttation in your house plants is to control your watering regime. Water your plants in the mornings or during the day, allowing any excess water to drain from the soil before it gets dark. Remember to also pour off any excess water that collects in the plant saucers. This not only prevents waterlogging of the soil, it also reduces the chance of guttation occurring.

Caution: in certain instances, the droplets from guttation can be dangerous to small children or pets. Try to avoid the possibility of guttation if you have toxic houseplants or have used any plant-protection products, or clean up the droplets straight away. Toxic compounds can easily be exuded through guttation and harm small children or animals.

What is the difference between transpiration and guttation?

Guttation is very different from transpiration. Both processes are normal and occur regularly in plants, but vary greatly in their processes. As discussed earlier, guttation is a process whereby liquid containing soluble minerals and sugars is forced out of the plant through special glands called hydathodes. Transpiration, on the other hand, is a regulated, passive process where water is pulled through the plant by water vapour evaporating from special cells in the leaf surfaces known as stomata. Transpiration is responsible for the circulation of sugars and soluble minerals throughout the plant, but only pure water is lost as water vapour.

When it comes to water droplets on leaves, guttation is also very different from dewdrops. Dew is the condensation of atmospheric water vapour on plants and surfaces. This occurs when the atmospheric air is saturated with moisture and there is a drop in temperature. The air can no longer hold as much water vapour, causing moisture to drop out of the air and condense on the surrounding environment.

Worried you may have toxic house plants? Learn how to identify houseplants in our detailed article on the subject.