Adding Calcium Carbonate for Bug Control??

Long Beach, CA

I found this and thought I would ask if anyone had ever heard of using Calcium Carbonate to control mites and other bugs in the worm bin? It appears on Aggie Horticulture / Texas AgriLife Extension Service, Texas A&M System. Your thought are very welcome!

Mites. "Red mites" or "fishworm mites" frequently become a limiting factor in worm production. They are natural inhabitants of manure and similar organic materials and all worm beds contain low-level populations of mites. Several species of mites are present in most worm beds, but the most important is the earthworm mite. These brown-to-reddish mites are small, although readily visible. They are found most abundantly near the surface and edges of worm beds and around feed concentrations. They do not normally attack earthworms, but they do consume worm feed. When mite populations are high, worms will stay deep in the beds and not come to the surface to feed, resulting in poor worm-growth and reproduction.

Control. The best control for earthworm mites is proper management. High mite populations are nearly always associated with one or more of the following conditions. (1) over-watering, (2) over-feeding, or (3) feeding of wet or fleshy garbage. Bed conditions ideal for worm production are not conducive to high mite populations. Feeding schedules should be maintained so that feed is consumed in a few days, thus preventing accumulations of "soured" feed in the beds.

Worm beds with poor drainage frequently become too wet, creating conditions less favorable to worms and more favorable to mites. Watering schedules should keep the beds moist but not wet.

High mite populations are frequently associated with the feeding of garbage, and other vegetable refuse having high moisture content. Such feed should be used with discretion.

When mites start to build up, uncover the beds and expose them to the sun for a few hours. Cut down on feed and water. Till the beds and
--->> add calcium carbonate every 1 to 3 days.

Helena, MT

Rhapsody616, nice posting. I have not seen anything of this nature posted here in DG, however I think most of us have experienced this problem as some time or another. It occurred once last year when I was experimenting with a heat mat under my worm bins which are located in an unheated, attached garage. I got the media too hot so I super hydrated each bin with copious amounts of water to restore them to a more normal condition. I got one bin in particular too wet and those red mites you mentioned did cover the surface and outer edges of the bin.
My solution was to add about 30 percent new media which is peat moss which has been soaked overnight and using an aquarium net, remove as much moisture as possible. I removed about a third of the old media and thoroughly mixed in the new media with the old. The new peat moss acted like a sponge removing the excess water in the bin, and the problem cleared up in a few days.
I feed each bin once or twice a week a blended emulsion consisting of kitchen vegetable scraps and egg shells. The technique I use is to dig a long trench, about six inches deep, on one side of the bin with a hand fork and place the removed media on the opposite side of the bin. I then add about a cup of coffee grounds, and two cups of the soaked and drained peat moss to the trench, and work it in with the hand fork. I then add the blended scraps and egg shells to the surface of the trench and wait several minutes until the excess moisture has drained into the mixed media below. I then mix the thickened emulsion in with the hand fork and cover with the old media which had been placed on the opposite side of the bin.
This procedure will maintain a fairly uniform moisture consistency throughout the bins without having to add additional water. Over watering has not occured with this method for me. The only times I have experienced a problem with too much water is when I’m not careful when adding additional water. And, no, I do not have holes in my 30 gallon plastic tubs!
I do see some tiny knats and spiders in my bins, but I don’t get alarmed by them. I don’t like spiders so I typically will smash them when present, but frankly they probably serve a purpose and I should leave them alone. If the knats are bothersome, those yellow sticky pads do a very nice job of collecting them.
As for calcium carbonate I presume they are referring to sodium bicarbonate or baking soda, which would probably be helpful in several ways. If you bins become too moist it would help to ‘sweeten’ your media as well as control the pest problems you mention. I have never used this material in my bins, so I couldn’t say for sure if it would affect the worms. Other than being a bit abrasive, I doubt that sodium bicarbonate would be harmful if not used in excess.
I will be interested in seeing the feedback on this from other DG’ers. Impressive posting….

Long Beach, CA

Thanks for answering my post. Calcium carbonate is limestone. I thought it was baking soda too! I like your solution to your wet bin. I have made a note of it for use later.

What do you think about putting the heating mat on top of the bin instead of under it? It should heat the sides of the bin... I think!

And what do you think about coir v peat?

Helena, MT

Rhapsody, I thought someone would bite on that calcium carbonate vs sodium bicarbonate. There is considerable difference between the two. Not having read the article you did, my first impression is calcium carbonate would be difficult to quantify in it's usage since no two bins are exactly alike and pH adjustment could be a bit drastic using limestone. Red wigglers are tough little critters and probably could withstand a sharp swing in pH, however I don't like the idea. As you are aware many people will thing if a little bit is good why not add some more, and that's where you get into trouble with limestone. Although sodium bicarbonate is a safe way to adjust pH a little at a time, I prefer the maintenance approach vs chemical whenever possible. If you would post the article you read I would like to take a look at it and see why they chose limestone and if they attempted to quantify it's usage.

I use a four foot, two bulb fluorscent lite fixture on top of my bins and I believe this lite fixture provides just as much heat as a heat mat would on the surface of your bin(s). The heat mat on the bottom can be very tricky to operate and you have to be very careful you control the moisture content in you media or you can bake you worms in quick order. I use a special timer which toggles on and off every fifteen minutes and can be adjusted to fit the needs of my bins, however don't leave town for a couple of weeks with out shutting off your heat mat like I did. I talked about this in another thread if you decide to look back about a year or so.

As for coir vs peat I would defer to others. There are a number of people here in DG who have tried both, and feel coir is easier to work with and lasts longer than peat moss. My method of removing up to an inch of dried media from the tops of the bins when I feed my worms, then replacing it with new media has kept my bins active for many years. I use the spent media about as fast as I remove it in germination and potting mixes. Never Enough!

I know too, that others use their spent coir in the same manner, and there many different ways to collect these 'worm castings'. Collecting worm castings is one of the main reasons for vermicomposting. Collecting 'worm tea' is another, although I don't like this process, preferring to make compost tea using some of the spent media in the formula.


Long Beach, CA

Here is the link:

My question is not about pH. My question is about mites. But your insight is greatly appreciated! I am still new to the worm bin thing. I just want to keep my worms in the bin (found many dried up on the floor) and keep the bugs out!


Helena, MT

Rhapsody, I will check the article out and get back with you. Thanks

You might take a tip from Motel 6 and leave the light on. Worms will run any time it's dark! If they still run or congregate in the corners of your bin then you have a problem.

Long Beach, CA

First off you are toooo funny! I will give my little one a bright night light!

Thanks again

Helena, MT

Rhapsody, I read through the article and could not find any reason for adding the calcium carbonate other than pH adjustment. Calcium carbonate or CaCO3 is probably the safest way chemically to make a pH adjustment, however I would prefer to stick with the maintenance suggestions which were made in this article. I didn't see anything really new in reading this article, but the suggestion for making a worm bed doesn't work well with red wigglers indoors. This bin is more for outdoors composting and fishing worms which are probably indigenous to Texas. Red wigglers are not well suited for bait. When my kids were younger we used them on tiny hooks with a cork for catching sunfish, but I haven't found many other game fish which like them. They are too soft to last on a hook for very long. I think that browsing past postings here in DG on media selections and maintenance suggestions will be more of a benefit to you. Typical of DG postings, the vermiculture section has numerous tips and suggestions which you typically don't find in books or articles on this subject. I copy and paste these as abstracts to my extensive files on numerous subjects found here. I have a complete filing cabinet full of data related to gardening projects, and much of the information has come from discussions here on DG. I consider it the PhD for information when you run out of information on garden subjects from books or the net. I don't think enough can be said for practical experience. Enough preaching for one day Rhapsody...good luck to you.

Long Beach, CA

Thanks again!

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