Floating Island Plants for Your Pond
Maintaining a healthy above ground pond in our domes depends on numerous factors. One of the most common questions we are asked pertains to controlling the algae growth in the pond garden. Floating pond planters are a perfect way to keep the algae away and add beauty!
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 floating pond planters 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!)
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.
Can you buy the floating pond planters premade?
Growing Spaces is selling the premade floating island planters while supplies last!
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 and How to Make an Aquatic Plant Protector.
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