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Duckweed Shade Test Results are In… and fireworks

July 5, 2012

Nothing too surprising here: I wanted to compare duckweed production in full sun production vs. three increasing amounts of shade.

1. Full sun for six hours and then shade in mid-afternoon made for fastest growth but consequently heaviest algae populations’

2. Best overall results: Three hours of full sun and then dappled shade gave almost as good of production as above, but not the algae issues. Results were based on visual observation.

3. Algae continued to be quite energetic in my sunniest pond but the more shaded ponds showed better ability to overcome the issue by corresponding degrees. Even though I tried to keep the same amount of duckweed cover on all surfaces, too much sun and possibly chemical fertilizer equaled algae.

4. The zen moment of realizing that algae is not the enemy. There IS no enemy, just Nature seeking balances.

When I relocated these duckweed ponds due to my landscaping project, I hadn’t counted on drought conditions. It takes four lengths of heavy, leaking garden hoses to reach the ponds. Quite frankly, it’s a real pain and one I’ve been avoiding at all costs. Now that I’ve got my shade answers,  as soon as I finish this post and two really good cups of Antigua coffee, I am going to march down to the valley armed with five gallon buckets, my trusty duckweed net and begin harvesting everything I possibly can. (No tadpoles will be harmed in this process if I can help it.)  I’m going to use all duckweed as mulch for my tomatoes. Then I’ll drag the smaller kiddie pools back up to the house and prep them for my next series of tests; optimal production with various concentrations of manure additions. Now that I have flat terrain very close to the house, will pick a spot with a good 3-4 hours of sunlight per day. Will be buying more kiddie pools. My backyard is going to look like a three-ring circus.

Oh, 4th of July fireworks…  Thanks, Burning Man, you have spoiled me forever with last year’s  incredible fireworks display the night we burned the Man. Every year, I look forward to watching our local fireworks display in Paducah, KY.  I’m normally one of those that  clap my hands and cheer in child-like wonder at the amazing starburst. Last night, I drove to the river front and got comfortably seated in the open hatch of my Prius. Surrounded by thousands of other onlookers, all ohhing and ahhing, I found myself yawning so much during the show, I climbed in my car and drove home while the show was still going on! Hope this isn’t a permanent condition…

4 Comments leave one →
  1. Susan Munroe permalink
    August 11, 2012 8:08 pm

    I was just driving along, thinking about where I could get some oat straw for my hen and duck bedding. My usual source changed to barley this year. Barley… barley straw is what people add to ponds to reduce algae… They usually add it confined in mesh bags or as a very small bale, probably for easy removal.

    I wonder what a wad of barley straw (wrapped with string to keep it together) added to a duckweed pool would do? Would it reduce algae there? Would it change the duckweed growth, pro or con?

    Sometimes my stream-of-consciousness thoughts produce interesting questions. Sometimes they just produce useless stuff.



    • August 12, 2012 12:26 pm

      Good idea on the barley. I like your stream of conscienceness! While a chemical in barley will kill or inhibit bluegreen algae, theoretically- it doesn’t hurt the duckweed. However, my sources on this are skimpy at this time. Would be a simple experiment to try.

      Last week, I heard a trick for slowing or killing algal growth in duckweed ponds last that is so simple, it’s a no-brainer. Algae needs sunlight so eliminate the sunlight by routinely stirring up the muddy bottom of your pond. This’ll inhibit the algae growth and allow the duckweed to gain leverage. Could use a compressed air hose nosed down in the bottom mud of large ponds. Could just manually stir small ponds from the bottom up. Will have to have a post on this. Keep up the random acts of inspiration!


  2. July 5, 2012 9:29 pm

    Hi Sue. It’s great you picked up on the UV Index as a potential limiter of duckweed production. As it turns out, intense UV radiation is a physiological stressor of duckweed. Different species react differently. A great read on this is a study done by Susan A. Collins back in 2000.
    As for algae vs duckweed as a green mulch… I was not picky about which aquatic species I ended up with, although duckweed has more protein AKA nitrogen than most algal strains. If I were wanting animal feed, it would be a different story.
    Glad you can move your ponds closer to your water source. It’ll save you some grief. I can just picture your ducks hopping in and out of each pool… 🙂


  3. July 5, 2012 1:23 pm

    That is valuable information for me. I was going to put my ponds in the sunniest spot, which is also farther from the house, but now I can put them closer. Of course, WA is not KY, but you give me a starting point.

    Algae is not the enemy, but it often isn’t what you want, either. But algae is also a good fertilizer, so if garden fertilizer is what you want, you’ve got it.

    I wonder if the UV Index has anything to do with photosynthesis? Right now at 11:30, mine is 8, yours is 9.

    Multiple wading pools… my Ancona duckies would go crazy!



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