Usually I tell houseplant owners to never leave their plants soaking too long in a saucer of water, but rather to empty it 15 to 20 minutes after they water, because roots that sit in water too long may begin to rot. And normally that’s very good advice.
But there are exceptions to that rule, a very small minority of plants that love it when their soil not just damp, but actually sopping wet. As a result, these plants prefer that you always leave their pot sitting in a saucer of water. Who knew?
Keep These Plants Wet
Baby’s tears (Soleirolia soleirolii, syn. Helxine soleirolii) belongs to this group. A lot of gardeners have given on this tiny, creeping, delicate-looking foliage plant with rounded mini-leaves, finding it very difficult to keep alive, and indeed, I doubt if one baby’s tears plant in ten is still alive a month after purchase: it really does die that quickly.
But that’s because people treat it like any other houseplant and let it dry out. Change tactics and just watch your thumb turn green.
Water it abundantly and let the pot soak in the water… always! When you see the saucer is nearly empty, don’t wait: add water. Just include a decent amount of light (medium or even low light is fine) t0 your care regime and your baby’s tears will live for years and will even need to be trimmed back occasionally so it won’t invade neighboring pots!
The same is true for the fiber-optic plant (Isolepis cernua, syn. Scirpus cernuus). This small plant carries tiny silvery inflorescences at the tips of its thin strongly arching grasslike stems, giving it the appearance of a dense bouquet of optical fibers. In the wild this plant is semi-aquatic: it’s essentially impossible to overwater it.
Leave it in a saucer that always contains water, offer it intense to medium light and it will live happily and for a long time!
Unlike the fiber-optic plant, the various selaginella or spikemoss species (Selaginella spp.), such as Kraus’ spikemoss (S. kraussiana), often used as “living moss” in terrariums, are not semi-aquatic. However, most still prefer that their soil always remain moist.
Since their roots are very short, they begin to suffer even before the potting mix has dried out completely, as the upper layer of mix, where their roots are concentrated, dries out well before the bottom layer. The secret to keeping spikemosses happy, therefore, is to always to leave water in their saucer. That way the water will rise up to their roots by capillarity.
Give them moderate light, high humidity (they simply hate dry air!) and constant watering and you will see your spikemosses really start to thrive!
Even More Water
A saucer full of water is not always enough for the umbrella palm or umbrella papyrus (Cyperus alternifolius).
This semi-aquatic plant is a natural air humidifier, drinking up water like a fish, then releasing the majority of this water to the air, to the great benefit of other plants in its vicinity. Unfortunately for the umbrella palm, this great generosity with water causes its saucer to empty out quickly, soon putting the plant in a state of considerable distress.
To satisfy it, use either a very large saucer and fill it to the brim, adding more water as needed or, even better, a large cachepot, one at least 4 inches (10 cm) larger than the pot it grows in. Since, by definition, a cachepot has no drainage hole, you can easily fill it with water to the level of the rootball or even inundate the rootball completely: it can stand being underwater to a depth of 2 inches (5 cm). Yes, the roots can remain permanently underwater without harming the health of the plant.
Whenever the water level drops significantly, add more water. Add to this constant flooding good light to full sun and your umbrella palm will never have been as happy!
There you go! There are just a few houseplants that prefer to constantly soak in water, but once you know which ones they are, you’ll have much better luck growing them!