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

How to Harvest a Soggy Wet Worm Bin?

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.

The Worm Bin Harvest

Table of Contents for this document:

Harvesting Vermiculture:

Harvesting Vermicastings (worm castings) and Worms:

Uses of Vermicastings:

WORM TEA from vermicastings or vermicompost:

WORM TEA from vermiculture -- direct:

SEEDS

DRYING the castings

HATCHING the worm cocoons

June 5, 2014 Edition

Once every three to four months the worm bin is ready for harvest.  The paper base in the bottom of the bin will be wet enough that it can’t absorb more water and the bottom of the vermiculture will start to get muddy.  To harvest the worm castings the vermiculture needs to be moist and crumbly – not muddy.

Harvesting Vermiculture:

Harvesting vermiculture without any screening -- to use as is -- does not require much work.  You simply divided the vermiculture from the worm bin in two and populate a new bin for yourself or to give away.

Harvesting Vermicastings (worm castings) and Worms:

I use a four mesh flat screen for the initial screening and an 8 or 10 mesh flat screen for the second screening.  First though, don’t even bother to try, if your vermiculture is too wet.  This is why I have emphasized maintaining the vermiculture at the right moisture level.  This is why I dump my bins and add dry newspaper to the bottom of the bin.  This is why I add dry newspaper strips to the top dressing and dry folded newspaper to the top.  The dry paper acts as a sponge to draw the water out of the vermiculture.  The goal is to have a moist, crumbly vermiculture to separate regardless of the separation technique.  At the right moisture the tiny castings do not stick together and are easy to work with.  When you do a separation you will end up with worms, worm castings and partially digested vermicompost, and stuff that won’t break down.  Worm cocoons end up with the worm castings and can be hatched in an additional process step.

Uses of Vermicastings: I use the worm castings as side dressing on plants, in the bottom of a furrow when planting, at 20% with potting soil when planting seedlings, or house plants.

WORM TEA from vermicastings or vermicompost:  I make aerated worm tea from the castings or compost.  Add one quart of castings or compost to 4 gallons of water in a 5 gallon pail.  Aerate with a fish tank bubbler for 12 hours; add one TBS molasses, aerate for another 12 hours, and use right away for best results.  I occasionally stir the tea with a paint stirrer powered by an electric drill to further aerate the tea.  Tea is a living culture of beneficial microbes and nutrients.

Uses of worm tea: My wife uses it to water house plants once a month and in the garden as a liquid fertilizer every two weeks.  She likes the convenience of the worm tea.

WORM TEA from vermiculture -- direct:  If you use vermiculture to make tea you can dump a quart of vermiculture,  worms and all, into 4 gallons of water and then strain out the worms and undigested material to put back in the bin – very quick and easy separation.  Then bubble the tea as above.

I like the convenience of making worm tea by this method.  I don’t have to spend time on the separation process.

The worms are used to repopulate the worm bin and to start new bins.

The undigested vermicompost goes back in the worm bin.  Eventually the worms and microbes eat or decompose nearly everything but some things take a lot longer than others.  For example the skin of an avocado may last a year -- the same for corn cobs.

SEEDS in the worm castings however either remain dormant and sprout in the garden or sprout in the bin.  Also carrot tops, beet tops and potatoes will often sprout and grow.

Keep weed seeds out of the worm bin.

Seeds that sprout while the castings are being stored can be screened out before use.  Storing the castings in cold storage for a few weeks can stratify the seeds and facilitate sprouting.  I have used this method to eliminate nearly all seeds from the castings.

DRYING the castings for long term storage requires the moisture be removed from the castings to the point that the microbes form spores (sporulate).  On a good drying day (sunshine, warm, low relative and some breeze) put the moist castings on a tarp in the driveway.  Turn them occasionally and when they are dry enough to slide off the tarp without sticking they are dry enough to store (estimate 5 to 6 hours).  Dry worm castings have a shelf life of at least three years.  In the winter the castings can be dried in a warm, dry room.  I use shallow cardboard boxes with a thin layer of castings spread over the bottom.  This process takes longer – 3 to 4 days.

HATCHING the worm cocoons that are collected with the castings requires another process step before you dry the castings.  (This is more work than most people are willing to undertake but it allows you to grow the size of your worm farm faster if that is your goal.)  I put the 4 mesh accepts from the first screening step into a bin with fresh food.  The food is put inside a mesh onion bag and buried in the castings.  After 10 days the mesh bag is removed and whatever worms have hatched and crawled inside the bag with the contents – worms and all – are removed and dumped into a worm bin.  This process is repeated until the mesh bag yields very few if any worms (2 to 3 months.)  The 4 mesh castings are now free of most of the cocoons that will hatch and can be screened through the 8 or 10 mesh screen to obtain the final product. The 8 or 10 mesh screen rejects go back into a worm bin for further digestion.  You will also recover some small worms in this final screening step.