Floating Plants

Floating Island Plants for your Pond

Maintaining a healthy water tank in our domes depends on numerous factors. One of the most common questions we are asked pertains to controlling the algae growth in the water tank.

Why do I have more algae in the winter?

It is important to understand that algae develop primarily from nutrients in the water and sunlight on the water surface. So, if you notice algae bloom in February on your tank’s surface, you’re not alone. Why? In the winter our cold-hardy vegetables generally are shorter in height than the summer vegetation, allowing maximum sunlight throughout the dome and specifically onto the water tank, our primary heat sink for the dome. With the sun lower on the horizon, the tank gets more sun from the north-wall Reflectix. With increased sunlight on the tank, algae often bloom on the water surface, as well as alongside the interior tank walls.

One trick to minimizing your algae growth is to increase plant coverage on your water surface. Ideally, your tank surface should have 60-70% shade coverage. My very favorite (and easiest) way to bring floral beauty and functionality to the water tank is by having free-floating water islands.

How are the islands made?

Water islands consist of rings of densely extruded foam, which are stacked, sewn together to make a basket, then filled with aquatic media and water plants. They float on their own, thereby reducing the probability of knocking plants off submerged plant pedestals. (Yes, before utilizing water islands, I knocked over several plants, causing an emergency recovery in our winter tank water! Not fun, ask my husband!)

Floating Plant

Typically the majority of the plants used in these islands are cold-hardy and will live year after year. The extruded foam material is critical, as the plant mass makes a substantial root ball and consequential weight, especially as the plants will live through the year(s). This extruded foam material makes up the bulk of the island’s cost, so it should never be tossed out. This makes your island investment sustainable. In my own unheated domes at 7800 feet altitude, I have numerous islands that have “floated” in my tanks for a decade, providing beauty year-round.

Claudia's Pond Plants
The plants in Claudia’s 22′ dome pond.

Can you buy them premade?

This year I will be working alongside Growing Spaces to supply fully planted islands upon your pre-order request. 

Islands are available in 2 sizes, 16” diameter and 18” diameter, costs are $130 and $160, respectively. Many dome owners have found that 2 islands can be enough for the 15’ and 18’ domes, 3-5 islands may be adequate for the 22’ and 26’ domes, and more for the round 33’ and the 42’ domes. For more ideas on how to provide aquatic plant coverage in larger domes, visit 
Create a Thriving Ecosystem in your Water-Tank & How to Make an Aquatic Plant Protector. This offer is no longer available.

Check back with us next Spring to see if the Floating Islands are available in your area.


  • Please send the brand and type of heavy soil that you use. I have 3 islands that you made me 2 years ago.
    The slimy soil that I got from a retailer last year was a dissaster!

    • Claudia makes a 50:50 mix of REAL topsoil with aquatic media. No additives, not even forest wood products. There are several brands of aquatic media on the market. Concerning the soil portion, you have to avoid anything with peat, coir, wood, perlite, etc. That would float out of the island and onto the water’s surface. But that mix also has to stay light in weight. Less soil mix is better than too much.

    • Thanks Lisa. Claudia hasn’t made the plants yet, and there are many types of water plants. So the best answer would be that the islands would be filled with various water plants, the majority of which will be hardy in nature and able to live through our Colorado winters in unheated water tanks.

  • I would be interested in the plants. I already have the containers we live at 6500 feet in Western Wyoming

  • I love these. I want to report that ours died in a freeze as the door to the dome was left open in winter when we were traveling, and they are ALL coming back now. Looking good! So exciting to see.
    I would love to do a workshop with Claudia on maintenance and cleaning of the islands.

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