All worm castings are NOT equal


Not All Worm Castings Are Equal: 

Worm castings that have been screened.

Worm castings that have been screened.

The dirt on worm castings…….

By D. Converse

None of the contents of this article may be reproduced without permission from the author.

Worm castings are a wonderful thing!  They have often been referred to as “Gardener’s Gold”, and with good reason. Worm castings are higher in plant available nutrients than any other fertilizer, compost  or manure. They also naturally contain plant growth hormones, beneficial enzymes, and an amazing live beneficial microbial population all which can be used at its highest benefit, if ones knows how. If you have not stopped by the intro article on this site I suggest you read this info too, “Worm Castings” found at this link:  .   BUT NOT ALL WORM CASTINGS ARE EQUAL.

Worm castings generated in a vermicomposting bin

These worm castings which were generated in this vermicomposting bin are ready for screening, or use as-is.

The best worm castings to use are the ones you were able to produce at your own home. Well, actually the redworms do it.  This is because you can have access to fresh worm castings year-round, without having to buy them.  Your own compostable trash can be part of the transformation that re-fills your refrigerator with nutritious veggies from your garden, or grows gorgeous blooms in your garden, or puts fruit on your trees/vines.  This is the BEST because it came from your home, from your own trash or farm waste.

If you are buying worm castings, or want to go beyond just producing good worm castings with your household trash, there are a few more pieces of information I will share here that will help. First thing you need to know is that NOT ALL WORM CASTINGS ARE EQUAL. So if you are buying worm castings and want to get your money’s worth, read on.  If you want to have more information to produce the best possible worm castings you can, also read on.  Now if you are just wanting to do vermicomposting in a bin at home, and not complicate things, do not fear, your redworms WILL produce a wonderful batch of worm castings from whatever compostable matter you can provide them (just avoid the no-no list for ‘food’ for worm bins – see our vermicomposting section on this website for details.), the following information is not necessary to get worm castings to use from your own worms.

The list below will give some information for those who are buying worm castings, or wanting to produce the best they can get from their redworms.

  1. When buying worm castings, do not purchase those that have been stored in an airtight container for any length of time. This includes sealed plastic bags, the convenient way soil and soil ammendments are found in the garden section of most stores.  Do not store your own harvested worm castings in sealed beneficial bacteriacontainers.  Worm castings are live.  The beneficial microbial population needs to breathe (great cartoon ‘photo’ of them on the right).  The worm castings need to be somewhat moist to stay alive. Worm castings that HAVE NOT been stored in airtight containers will have live populations that allow the worm castings to be used as more than just a wonderful fertilizer, and for soil structure improvement.  Live worm castings can also be used to get rid of insect pests (such as spider mites, aphids, tomato horn worms, just to name only a few) , and stop plant maladies (such as  powdery mildew, damping off, blight, black spot, only to name a few). To do this though, a ‘brewed’ worm casting tea needs to be made .  The simple instructions can be found on this in the article “Our Original and Perfect Worm Castings Tea”.  Here is the link:   This is not possible with dead worm castings that have been stored in airtight containers.  If you are going to buy worm castings, you might as well get you money’s worth and shop for live castings available in bulk open bins, woven or other breathable bags, open containers…. DO NOT BUY WORM CASTINGS PACKAGED LIKE THIS:
  2. worm castings in sealed bucketsealed bag 2Sealed bag 1


2. It is a scientifically proven fact that worm castings generated from pig manure out Fodder pigs having a mealperformed all other worm castings.  Yes, someone ACTUALLY scientifically studied and field tested this!  They even compared an amazing array of manures as food stocks for redworms.  The study was done by the Ohio State University Soils Lab, and the published findings of that study are available online. Now before you decide never to touch worm castings again, keep reading.  There is more good news.  It is also a scientifically proven fact that matter which goes through the gut of the worms comes out completely safe and clean.  In fact, in India, officials are gaining control of the open sewer/human disease issue by adding worms.  Worms consume and kill pathogens that cause human diseases. Worm castings are completely clean!  A side note: India is home to some of the world’s leading vermiculture/vermicomposting research.  So you can feel confident when working with worm castings generated from manures.

3.  Worm castings and worm compost are not the same thing. Please LOOK at worm castings you are using from your own bin, or buying.  There IS a difference between worm compost and worm castings.  Many who are not aware of it, use the terms interchangeably.  Worm castings are the worm poop, and ONLY worm poop. It is not other matter that is decomposing along with the worm castings – it must have gone through the gut of the worm to be worm castings.  Look at the picture at the top of this article.  It is a close up shot of screened worm castings.  Worm castings should look like very fine coffee grounds.  It can be very wet, and still look like this.  Many people try to sell matter that has not been completely processed by the worms, and should actually be called worm compost, but are labeling it worm castings.  Worm compost IS FINE to use, BUT you need to be aware, that manures (not yet processed through the gut of the worm) and other matter it contains, are not as safe as truly completely worm processed matter is. Decomposed food scraps do contain bacteria you probably do not want to run through your fingers. Some of those can potentially cause havoc with your garden and soil. Keep in mind, that vermicomposting is a cold composting process.  There is no heat to kill bacteria (that is why it is important to be sure the worms do it completely – and worms are VERY GOOD at what they do.).  Using this this matter  ( the stuff not completely run through the gut of the worm) to make worm casting tea can pose a problem, in blooming undesireable microbes as well, and may spell disaster for an already ailing crop, or your soil.  I do not recommend using any worm compost that is not entirely processed, for anything other than an excellent fertilizer.. At the very least, be sure to wear gloves and wash your hands before touching anything else if you are using worm compost. Even with manures used as feedstock for worms, the fully processed worm castings will not stink. Worm castings should always have a pleasant earthy aroma, that is not that noticeable

4) So HOW do we get our worm castings screened?   Our commercial trade secret…But the same results can be achieved by anyone willing to do the work.  “Screening” is needed.  At the largest, use 1/2″ hardware cloth, however we really recommend 1/4″ size.  FOr a finely screened top notch product, the best thing to use is window gauge screening, which allows the granules of each worm cast to pass through but not the worm cocoons. This smaller gauge is important if you want to keep your worm reproduction in one area, although having redworms hatching in  your planter pots, and other garden areas will be of great benefit,soil sifter and not a worry. Be aware, the most people have difficulty using a window gauge screen and really it is not necessary for the home vermicomposting operation. If you cannot get your worm castings through  screens, because it is too wet,, or just plain do not have access to screening materials, have no fear.  Unless you are selling your worm castings, screening step can be skipped, as long as you are not particular about clumpy looking ‘soil’ matter. If you really have the need to have screened looking castings, use the same technique for sifting soil over a wheel barrow, just like the set up pictured on the right.

Of course, I always encourage people to use what they have to generate their own worm castings.  You will not go wrong there:  Refrigerator ‘experiments’ that you did not get a grant for, shredded bills you don’t want to pay, petrified pizza you found under your teenager’s bed, stale bread, kitchen waste, barn matter, raked autumn leaves (avoid a lot of oak leaves due to the high level of tannic acid they contain) and the list goes on.  Just be aware that if you are buying worm castings, you will get the biggest bang for your buck if it was generated from (at least in part) from pig manures.  This is why we keep the ‘poopster crew’ on our farm.  Part of the crew is pictured in the previous paragraph.

3. Article still in progress…….