Predatory Nematodes and Composting Redworms

by Enraged Poet
(NY)

Will predatory nematodes have a negative or harmful effect on redworms used for composting? I figure on adding them, as long as they're not harmful. Could I possibly breed them in my organic soil and cut on costs?

Answer: Poet- predatory nematodes attack and feed on many pathogens and microscopic harmful insects in the soil. The key is "microscopic"....these little guys won't hurt anything as big as a redworm. In fact, by eliminating mite eggs, fungus gnat larvae, thrips, and other harmful insects from the soil, they actually benefit the redworms.

Properly made compost works so well in part because the manufacturing process tips the living conditions in the soil in favor of beneficial insects and micro-organisms....and out of favor of harmful insects and pathogens. In other words, healthy compost should already contain a population of predatory nematodes. If you have a source of good compost, I suggest making fresh brewed compost tea.

Adding some healthy compost to a few gallons of water inoculates it with a whole host of beneficials....cellulose decomposers, chitosan decomposers, humic acid producers, predatory nematodes, and others. Now here is what you do to turn a hundred thousand micro-organisms into millions and millions....

All of the beneficial micro-organisms you want are aerobic, so you will want to add an aquarium air pump and air stone to the compost tea. Add some source of seaweed....either a couple shots of liquid seaweed like Maxicrop or else some kelp meal (1/4 cup should work for a couple gallons of water). If you really want to supercharge the process, add a little rock dust and/or a quarter cup of un-sulfured molasses.

The micro-organisms use the carbohydrates from the seaweed as food, providing building blocks for cell division and multiplication. The sugar source provides extra energy and speeds up the process further. It only takes one or two days of brewing for the population of beneficial micro-organisms to explode....you will see a "froth" around the sides of the brewing container.

Really, you only need a cup of this stuff added to the water when you water or fertilize your plants, although giving them more will not do any harm. Just like compost, adding all these beneficials to your soil stacks the deck against harmful insects and pathogens. I have had friends- indoor gardeners using soil- who purchased beneficial nematodes, but they saw no added benefit above and beyond what they were already getting from using fresh compost tea.

So I would recommend using a little compost, and especially fresh brewed compost tea, wherever you feel you need the predatory nematodes....no sense in spending the money if you really don't need to. Happy Growing!