Greenhouse Tank Gardening

We’re looking for advice for gardening/fish growing in our tank.  We are a school in Virginia with a 33″ dome and 2300 gallon circular tank.  The kids are interested in creating an edible ecosystem in the tank.  We’re hoping for advice on species selection, sources, basic management, etc.  Any input would be really great and greatly appreciated!

Thank you!

-MCS Middle School


  1. Although,I do not have much experience with edible water gardening, Watercress is edible and could grow well in the Growing Dome water tank. You may want to “google” edible water plants.

    Also, try researching hydroponic methods of growing regular vegetables, for example tomatoes. Roots are kept in water instead of soil. When using these methods it is smart to keep fish out of the tank, as they will most likely nibble at the plant roots..

    Aquatic plants have done quite well in the tank of our 33′ dome. Duckweed & Water Hyacinth (may be wrong spelling) are two examples of what is doing well in our tank. The fish love the plants, they make the perfect natural eco-system for the fish!

    I would love to know which Aquatic Plants others have in their tank!

    • Tenesha we sure do. You can follow us at www. . We will have our direct link to twitter back up soon. Glad you like the blog!! We appreciate all of your comments, questions, and feedback. Happy Growing.

  2. I need advice about the 33 ft dome’s water tank. I just started working at a preschool that had a dome installed in 2012. I am responsible for bringing it back to life, so to speak. The tank is home to 9 small koi, but algae has taken over the entire tank. There are a few tiny lily pads, also covered in algae. The fish seem to be very healthy, but the water is so dark that we can only see them during feeding time. What is the most effective way to solve the problem?

    • Valerie,

      Thank you for reaching out to Growing Spaces! I can certainly provide you with some advice. The above ground pond may have algae, but it is not all that difficult to solve the problem. Some algae is not a bad thing. Too much of it can be unhealthy for the fish, as they do rob the water of dissolved oxygen. First off, you will want to get this pond maintenance kit from The Pond Guy:

      This kit contains beneficial bacteria and microorganisms that consume and eat the algae. Within Just a few days you will find algae plant matter floating to the surface. You can skim this off of the surface and add it to your compost pile.

      The next thing you want to do is ensure that 65-85% of the pond surface is shaded with floating water plants. You can use water lettuce, water hyacinth, azolla, duck weed, floating water islands with various plants from the pond store, or a combination. Shading the surface of the pond will reduce the amount of light entering the pond, and prevent algae blooms in the future. Spring and Fall are the most common times to see algae blooms, so be sure that the pond is adequately shaded during these times. If you would rather not bother with floating plants, you can always use lattice, 90% shade cloth, or something similar to shade the pond.

      I will also send you an email directly.

      Hope this helps,


  3. Kyle,

    How does the freezing temperature in winter affect the advice you gave above? Surface of the water in my dome freezes and killed the duckweed last year. Do new plants have to be purchased and added to the tank every year, or are there some to focus on that will survive the winter and come back perennially?

    Also is it a good idea to use a heater in the water during the winter? Are dome is off-grid. Can you recommend a solar powered set-up system for keeping the water above freezing?

    • Shlomy,

      In the winter months, algae is not usually a problem because of both cold temperatures and less light. Also, the sun stays lower in the horizon in the winter which keeps direct sunlight from reaching the surface of the pond. In my experience, some of our water plants will die off in the winter months. There is nothing we can really do for certain plants, as they are not hardy. Some plants can tolerate cold temperatures and make it though the winter. The plants we loose in the winter are typically replaced with a new batch in the spring. Azolla and duckweed are some of the hardiest plants that we have. I don’t think I have ever seen them completely die off. We also don’t usually see the surface of the pond freeze over. Southern burner heaters will help keep your tank warm in the winter months. Check out this link for more info on heating the Growing Dome: You could also do a DIY solar thermal system and run a closed loop coil in the pond, but that is a lot of work for what it is worth. Such a system is still dependent on sunlight, whereas the southern burner heater is not. We usually use a small 20 gallon propane tank with the southern burner non-vented unit.

Leave a Reply