OUTLINE OF HARVESTING PROCEDURE
TO OBTAIN WORM CASTINGS
FROM A WORM BIN
June 9, 2014 Edition
1 -- Open the worm bin and dig down to the base paper to assess if the moisture is too wet to screen.
If the bin is moist and the vermiculture crumbly then it can be screened -- proceed to step 2. If it is muddy and too wet to screen, add dry material and postpone the harvest for at least two weeks. Refer to post
2 -- Dump the worm bin into the large tote.
Use the rubber spatula and paint brush to clean most of the castings out of the worm bin into the large tote.
Use paint brush to clean the castings off the wooden base and put the base back into the worm bin.
3 -- measure out 2 pounds of dry folded newspaper and put it into the worm bin on top of the wooden base. Overlap the sheets of newspaper to completely cover the wooden base.
The newspaper acts as a sponge that will soak up the excess moisture that works its way to the bottom of the bin. In another 3 to 4 months the newspaper will be saturated with water and need to be replaced again.
4 -- now tear up the wet newspaper that is in the old base paper and set it aside in an empty tote. This will be used as bedding if needed to bring the level in the worm bin up to the molded line on the side of the bin (about 4 inches down from the top lip of the bin.)
As we screen the vermiculture the rejects (rejects are what doesn’t pass through the screen) go back into the worm bin. If there is sufficient volume of rejects to fill the worm bin to the molded line additional bedding isn’t needed.
5 -- now start the screening process using the 4 mesh sieve. I screen the vermiculture right back into the large tote and put the rejects into the worm bin.
I screen the vermiculture several times (at least two times) through the 4 mesh sieve before trying to switch to the finer sieve (either an 8 mesh or 10 mesh). The reason being that screening through the the 4 mesh sieve is quicker and after several passes nearly all the adult worms will be rejected and returned to the worm bin. Small worms and cocoons are not removed from the castings by the 4 mesh sieve. The 10 mesh sieve removes many cocoons and nearly all of the small worms. The 8 mesh is similar but not quite as efficient as the 10 mesh.
Note about sieves: The coarsest sieve is 4 mesh which means there are 4 openings per inch. The two finer sieves are 8 mesh (8 openings per inch) and 10 mesh. The 10 mesh is the finest sieve I use. It screens out nearly everything but very small undigested material and some very small seeds (tomato for example). The accepts of the 10 mesh sieve is nearly all worm castings. The castings need to be pretty dry in order to screen them through the 10 mesh sieve. I often will stockpile 4 mesh accepts and dry them some before I try to screen them through the 10 mesh sieve.
6 -- Storage and shelf life:
4 mesh accepts, not dried: This is best used right away. Since it still has some worms, worm cocoons and compostable material, it is not “stable” enough for long term storage. In the winter it can be stored as is in an outside shed and allowed to freeze. Once the weather warms it needs to be used or processed further to stabilize it. Don’t seal undried castings in an airtight container -- they will continue to “work” and go anaerobic after they use up the oxygen -- let them breath.
8 and 10 mesh castings, not dried: Best to use right away or store in a cold place -- same as the 4 mesh accepts. These castings are more stable than the 4 mesh castings because more of the compostable material has been removed. While the castings are damp they will mold and mildew. I don’t believe this hurts the efficacy of the product but it doesn’t smell or look good when it molds. Don’t seal in an airtight container -- it will continue to work and go anaerobic.
8 or 10 mesh castings, dried: Have a long shelf life -- 3 plus years. If you don’t have immediate need for the castings then dry them and they will be ready to use when you need them. You can store dried castings in an airtight container. The microbes form spores and stay dormant until the moisture and temperature are right for them to start growing again.