Here’s a really cool compact way to add plants to a room. It’s a simple indoor water garden, an exciting trend is known as ‘wabi-kusa’ in the aquascaping world. They make special dishes for this, but you can improvise.

Indoor Water Garden using Water Loving Perennials?

Shallow wabi-kusa for water loving perennials?
(Sophie La Berre)

It started in Japan a few years ago, as a simplified offshoot of aquascaping. But instead of growing underwater plants, this form of water gardening indoors makes use of semi-aquatic plants that live in boggy conditions. They are shallow-rooted and need consistently wet conditions. And there’s no complicated aquatic equipment needed. Just a wide container that is probably clear glass.

You can buy semi-aquatic plants, cuttings, or their seeds from different specialty suppliers. Check aquarium stores in your city, especially those who advertise about aquascaping. You can also find them online. Tropics 1-2 Grow (sold in many countries) appears to offer plants for both submerged (underwater) and emerged (heads above water) growing. Apparently, they ship super fast too, so the plants arrive in great condition.

There are other possibilities too – check out this saxifrage ‘bonsai’ image on the right. Makes me curious if mini hostas wouldn’t be besotted with this planting situation. Maybe Forget Me Knots, which adore pond life. Both shade lovers, so it might be worth testing out.

Unlike underwater plants, those grown in wabi-kusa gardens don’t require oxygenated water. They get their oxygen out of the air in a room. Other than water and an appropriate container, all you need is substrate for planting in, and good light. You can also add some decorative bits too, like driftwood, interesting rocks and stones, sand and gravel.

Let’s start with the substrate, which is also often referred to as a wabi-kusa ball. You can make your own, but they aren’t that expensive to buy. Homemade substrate balls will give you murky water, because the outer layer is made of clay. Evidently, the a secret to having crystal clear water is simply dry grass wrapped around stones. The stones keep the ball from floating, and probably function a lot like hydroton in hydroponic net cups – something solid for roots to hang onto. No doubt they also act as a foundation for the structure that prevent collapse during planting and maintenance.

Before planting, the substrate ball is wrapped with moss secured in place using fishing line. It then has to soak for a few days. Once it’s saturated, you add your plants, then create a humidity dome with plastic food wrap. Even from seed or cuttings, plants that grow in these conditions are fast to germinate or form roots. Not surprising, since they have constant moisture between the water in the dish and the moss wrap. You will need some super long tweezers and a pair of sharp scissors – the kind sold for aquascaping. You’ll see these in the videos as we go along.

Like all plants, they need some nutrients. One how-to says you add the fertilizer to the water after planting, but only according to bottle directions. Too much causes problems with algae. But other tutorials and threads show that whether grass or clay encased, professional substrate balls often come pre-loaded with slow-release fertilizer tabs. That makes no nutrient additions needed for up to 6 months. If you make your own substrate balls, you can buy the fertilizer tabs from an aquascaping supply.

After 2 weeks you remove the plastic wrap – a little at a time. Just like hardening garden seedlings off to deal with outdoor conditions, you have to let the wabi-kusa garden plants slowly adjust to the humidity level in the room. Start with a single knife poke on the top, making the slit a little longer each day.

Maintaining your indoor water garden is pretty easy. Mist with water at least twice a day, and replenish the nutrients regularly. Some people groom their wabi-kusa plants. This requires super sharp shears. Once again, the perfect tools come from aquascaping vendors. And it’s probably wise to disinfect them each time you do some shaping. Other than that, the water needs changing regularly too.

And then there is the light. You can buy special wabi-kusa lights online, but they are pricey. Of course, it’s not just a light, but a base to hold the container with a properly positioned, adjustable lamp arm. Naturally, most people look for something more affordable.

Some say you can keep these tiny water gardens in a windowsill. This probably best in warmer climates, because windowsills are pretty chilly locations in the North in winter, and cloudy weather starves plant energy. But an indoor water garden doesn’t require an energy hungry light. The color of light isn’t important – but the intensity is. It can be white LED light instead of blue, which really makes the water garden a showpiece.

One aquarium discussion thread says a 15-20W CFL or a 10-15W LED bulb will work – it all depends on bulb efficiency. Just put it in a cheap adjustable desk lamp. Ikea has a sleek looking, adjustable LED work lamp with enough lumens at a great price that comes in a selection of finishes. And if you’re handy and creative, you could probably do something nifty with repurposed wood to make this aquarium clip light work nicely.

There you go – another cool indoor gardening project. Imagine something like that brightening up the drab spot in the corner! If your dish is big enough, and deep enough, you can also add a couple fish. Consider creating a series of these small gardens, and display them like art.

Here’s a video to explain some of the basics of getting started at water gardening indoors with this simplified version of aquascaping.

Naturally, there’s more to know. Haunt your local aquarium or aquascaping shop, check out the links below, or just Google for more.

More Info & Sources:

Top image courtesy of Kiran/Planted Tank

Tammy Clayton

Tammy Clayton

Contributing Writer at Garden Culture Magazine
Tammy has been immersed in the world of plants and growing since her first job as an assistant weeder at the tender age of 8. Heavily influenced by a former life as a landscape designer and nursery owner, she swears good looking plants follow her home.
Tammy Clayton