Predatory Nematodes and Composting Redworms

by Enraged Poet

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 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 sense in spending the money if you really don't need to. Happy Growing!

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Jan 10, 2014
vermicompost and nematodes NEW
by: Anonymous

Your vermicompost will be chok full of beneficial microorganisms. Many of these are airborne or naturally on your veggie scraps. No need to differentiate. I do agree that adding some humus or good compost from a wild environment would be a good idea. I have made tea from my worm bins and looked at it under the microscope and it has tons and a huge variety of nematodes in it as well as microorganisms and fungi. Can't go wrong this way.

Dec 31, 2009
nematodes, and tea question
by: Anonymous

Well I suppose my question wasn't as specific as it should have been-though I really liked the thorough response! Thanks!; having started a compost tray-style worm bin from organic indoor house scraps newspaper and corrugated cardboard, can I be assured that a colony of nematodes will find a way in and start in it?

and a question of the tea---I'd heard of raising bought microbe additives with molasses before, but this sounds excellent; my question, if one used half a large bucket of water, and an adjustable air compressor wand, to aerate it-till it's near the top, violently, could the process be sped up?

another note, my tray setup makes tea in the bottom tray; perhaps I could just add the kelp and molasses and a fish pump and let it work simultaneous with the worms, only using the air compressor for the warm months and the large outdoor garden?


Answer: Poet- garden compost (from a compost pile) and vermi-compost are different from each other, in that garden compost is made by decomposing organic material with millions of beneficial micro-organisms, whereas vermi-composting uses mainly the redworms.

While nematodes populate garden compost, I'm just not sure if they would populate vermi-compost the same way. Adding a handful of garden compost to your worm bin would introduce a population of nematodes to the vermi-compost if you want to give it a try.

There isn't a whole lot you can do to speed up the brewing process of compost tea....growing a large population of beneficials is limited in speed by cell division. A temperature just a few degrees warmer might speed it up a little bit, but if you have ever made your own wine you know that this would also give pathogens the advantage over the beneficials.

Last, you won't be able to make compost tea from your least not the same kind I described to you. Don't get me wrong- vermi-compost tea is an excellent additive in it's own right....but you want to use garden compost for the kind of compost tea I describe, because it is the beneficial micro-organisms that made the compost that you want to increase.

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