Transplanting Duckweed Tips
Duckweed is quite simple to grow. Ignore it and it’ll thrive.
Note: This is a reprint from Feb/2012. I am getting so many requests on how to transplant duckweed- thought you might like to read it again.
Getting transplanted duckweed off to a good start requires attending to its basic needs from the beginning. Here is the method I use for growing blockbuster stands of healthy, nutritious duckweed.
1. Assemble temporary growing container(s) for receiving fresh duckweed specimens. Container sizes can be anywhere from a quart jar to a 2.5 gallon bucket. Decide on an indoor growing spot near filtered light or outdoors in partial shade.
If duckweed is sourced from local ponds, include water that the duckweed grew in, as well as some mud from the pond bottom. This will insure enough micronutrients to carry your duckweed through the transition from the wild to your garden. If no pond mud is available, use a shovel of garden soil for every ten gallons of water
2. Once home, if you need to add water, rain water is best but if you must use tap water, let it sit out the night before to evaporate the chlorine. In my experience, once you have a firmly established colony of duckweed, a little water straight from the tap doesn’t seem to make any difference.
3. Go easy on any kind of fertilizer for the first few days to allow the duckweed a chance to acclimate to its new surroundings. However, introducing duckweed to clean, sterile water will cause it to go into shock and/or starve to death unless you add a very weak dilution of store-bought organic fertilizer or a small transfusion of compost tea for an end color of weak tea.
If you are planning to use store-bought fertilizer, following the company directions for a weak solution. Dilute that by 50% as well and only use it to supplement no more than 10% of the volume of your growing container.
4. For those of you with a pH meter, shoot for a pH of 6.5 to 7.2 . If above 7.2, you can add a small piece or two of wood or peat. If below 6.5, you can add crushed coral or a small piece of limestone to bring the pH back up. Pulverized egg shells work well, but need to be placed in a piece of cloth and tied up like a tea bag before placing in the growing medium.
5. After a few days of adjustment to its surroundings, duckweed can accept a slightly stronger nutrient feeding and a bit more light. If roots of your duckweed exceed 1.5 inches, this signals that your nutrient solution is too weak and you need to add more nutrients, more often. Healthy duckweed has roots that are ¼ to ½ inch long with bright green leaf color.
6. If you are planning to grow your duckweed in a stocked fish aquarium, the nitrogen from the fish waste will have your duckweed thriving in no time. Just insure that you have enough duckweed to form a colony half the surface area of your aquarium. Any less and you run the risk of your tropical fish eating so much that you lose your entire crop.
Note: Assuming that you still have duckweed left after your fish have their feeding frenzy, be aware that given normal aquarium light and even a minimal amount of fish waste nutrients, your aquarium will more than likely become known as your “DUCKWEED” aquarium. It will be difficult to revert it back to just a goldfish tank. Any excess duckweed can always be strained off and deposited around potted plants nearby, thrown in your compost pile, given to outdoor animals or many other applications. See also, “Fish/Duckweed Cohabitation Tips and Tricks”