Avoiding overfeeding is easy.  When you dig down into the next zone to be fed (following your rotation), if you see recognizable scraps, don’t feed then, but return in a week.  You can bury that batch in your garden.  If the only thing recognizable is egg shells & avocado pits, I go ahead & bury it.

During the first rotation - i.e. the very first time you feed each zone,  your worm population will be low, so make the feeding amount lower - maybe 4-5 quarts per feeding (for a 65 gallon bin).

I keep a 5-gallon bucket of water for watering, next to the bin.  It’s convenient and chlorine dissipates from standing water.  Chlorine’s job is to kill microbes;  the composter’s job is to cultivate them.   The EPA’s website, however, says that chloramines, which some water companies use instead of chlorine, “does not rapidly dissipate on standing”.*

Any liquid that’s been in the fridge too long, other than citrus or salty, can be poured over the bin, adding nutrients.  I tend to err on the side of under-watering.  An overly soggy bin will not allow air to circulate, which is necessary for the worms and the aerobic bacteria.

*If anybody knows how long a 5-gallon bucket of water must stand before chloramine fully dissipates, please reply.

My background:  I’ve taught vermicomposting workshops sponsored by Ecology Action in Santa Cruz, CA, contributed to their brochure, & built bins for the Agroecology Farm & Garden at UCSC.    I recently built a bin for the local elementary school’s garden garden project, talked to a class about the process, and will be helping them maintain it.

Indoors

The advantages of an indoor bin are:

• It will stay warm (& therefore more active) in the winter.
• It’s convenient.
• You won’t have to rodent-proof the bin (assuming your house is rodent proof!).

Disadvantages:

The indoor bin needs to have a drain spout, whereas outdoors you can just drill holes in the bottom & let the bin drain onto the soil.

You might have to win a debate with your spouse/housemates that it will not smell or attract insects (which is absolutely true if maintained properly).

Outdoors

If an indoor bin is out of the question, it should be as well protected from the elements as possible - at least out of the rain and direct sun.  If your winters get very cold, you may want to lay soil warming cables at the bottom of the bin (see Winterizing Your Outdoor Bin).  In that case, you’ll need to put the bin near a safe electrical outlet.

Consider there will inevitably be some excess water dripping from the bottom of the bin.

Be aware that it will probably attract the attention of rodents, but not to worry, there are ways to keep them out.    See Keeping Out Rodents

Plastic storage bins are easily converted to worm bins.  I recommend the Rubbermaid 50 gallon bin, which sells for under $20.  Many worm composting instructions show the use of a smaller bin, but unless it’s for

indoors & space is a consideration, larger size is preferable for two reasons:  1)  higher capacity (it can process more of your kitchen scraps), and 2) the larger bin provides more thermal mass, & if kept outdoors, is better able to survive winter temperatures. The dimensions of this bin are 42.7″ L x 21.4″ W x 18″ H.

Drainage

To keep the bin at the optimum moisture level, you’ll need to sprinkle water on it occasionally.   The excess needs to flow out the bottom.  You could just drill holes in the bottom, but there’s an easy way to collect the overflow:

Buy  2)  1/2″ PVC pipes the length of the bin, plus 3″.

Drill 3/16″ holes all along one side of the pipes.  If you drill along the writing on the pipe, it will keep your holes on one side, over the entire length.

Drill 2 holes in the bottom of the side of the bin, at one end, so that they can lay on the very bottom of the bin, and stick out the end.

Insert the pipes in these holes, & position them so the holes in the pipe face up.

Seal the holes in the bin (where the pipe goes thru) with silicon seal.  Glue them into a “T” so that it will keep the holes facing up, which is critical; it won’t drain otherwise.  The idea is that water will collect at the bottom & rise to the level of the holes, then flow into the pipe & out the end.

Aeration

Another important consideration in any bin is adequate air circulation.  Usually, the instructions are to just drill holes in the sides of the bin.  I recommend covering the bottom of your bin, as a first layer,  with 2″ - 3″ of gravel (approx 1/2″ rocks).  This will allow you to drill larger holes (1/2″) all around the bottom of the sides of the bin, and allow air flow throughout the entire bottom of the bin.

To the right is the completed bin, with temperature graph, spike thermometer, & plexiglass window, for an elementary school garden.

Wood Bin

Another good option is the bin made from plywood & 2×4’s, measuring roughly 2′ x 4′.  Its capacity is approx. 65 gal, about a third more volume than the plastic bin described above.  It’s very durable, and easy to attach foam board insulation for winterizing.  If you’re up for this wood project, here are the two best plans I’ve found:

http://www.seattletilth.org/learn/resources-1/compost/WormBinPlans.pdf/view

And more detailed plans with a very informative sheet:
http://www.co.whatcom.wa.us/publicworks/pdf/solidwaste/worm.pdf

Other Creative Solutions

There are other options for making  a worm bin.  You can use any sturdy container that has a favorable surface area to depth ratio, i.e. it is longer & wider than it is deep.  A 5-gallon bucket would not be a good choice for this reason.

Here’s a picture of an old kitchen sink I found.  I put approx. 1 quart of gravel over the bottom drain so it wouldn’t clog, and to deter who knows what from burrowing up into the bin.  There are no air holes in the side, but since it’s my second bin (for extra scraps); it’s an experiment to see how well it would work.

Also called vermicomposting, it is the process of reclaiming the nutrients in food waste, by cultivating red worms.  The worms eat kitchen scraps and their waste, called castings, is used as a soil amendment.

What should I feed (& not feed) the worms?

Anything that will decay is fine.  Avoid large amounts of citrus or raw onions.  See the article  Feeding: What to Feed & not to Feed

Can I start my bin with worms I dig up in the yard?

No, those greyish worms are a different kind.  They construct semi-permanent burrows, & are not suited for composting.  Red worms (Eisenia fetida*) are “crevice dwellers” & eat decomposing vegetation in nature.  They’re available online & at local fishing bait shops.         *also spelled “foetida”

I’ve heard that I need to use “bedding” in the bin.  What’s that about?

I use castings to amend the soil when planting a start into the garden.  After digging the hole, I add a handful of castings & other amendments, & dig it into the surrounding soil.  When making up potting soil for a houseplant, I make castings to be a third or less, of the mix.  Also, when sowing seeds in a flat, I cover the seeds with sifted worm castings.

I also occasionally top dress house plants by adding a small amount to the top of the pot.  You could top dress your garden plants also, but it’s not utilized as efficiently as getting it down in the root zone when first transplanted.

Actively Aerated Compost Tea (AACT)

Last summer I learned about actively aerated compost tea from reading Teaming With Microbes by Lowenfels & Lewis.  To make AACT, you put castings (or regular compost) in a porous bag, which goes into a 5 gallon bucket of de-chlorinated water, & aerate it for 12 hours using an air blower.  I have the 5-gallon setup sold by KIS.  The purpose is to exponentially increase the population of beneficial, aerobic microbes; and apply this tea to the soil & leaf surfaces.  These authors state that the bacterial population grows from 1 billion in a teaspoon of compost to 4 billion in a teaspoon of AACT.  That’s 1 teaspoon out of 5 gallons!  As a practical matter, AACT apparently supports plant health by increasing nutrient cycling, suppressing disease (by outcompeting pathogens for space and food), and improving soil structure.

Here’s a good article on the subject.

http://www.soilfoodweb.com/03_about_us/approach_pgs/c_03a_aerated_tea.html

There are many ways to harvest castings, but what makes this method easy is that there’s no set-up, and it’s incorporated into the feeding process.   You can use this method after the bin is at least 1 year old, and you’re no longer adding bedding because the bin has been entirely converted to castings, and you’re burying the food scraps in the castings.

When I harvest castings, I do it just before feeding, not only because of the convenience of combining the tasks, but there’s another efficiency, as you will see.

First I note which zone is up next to be fed - by checking my notebook where I record feeding dates.  The idea is to harvest from an area where there are the fewest worms; the zone which was fed longest ago will be least attractive to the worms.

From this zone, I push aside the leaves exposing the castings, loosen them with a claw cultivator & remove the castings to a 5 gallon bucket kept next to the bin.  It works out nicely because in doing this, you’re also digging a feeding hole just where it’s needed.

I scoop up both hand fulls & let it sift thru my fingers, checking for worms before removing it. I crumble any clods so I don’t take any worms. There will be a few worms, and an occasional avocado pit that I toss aside.  And in a few minutes I have 2-3 gallons of castings.  My experience is that once down into the bottom half of the hole, there will be many worms, & this is where I stop harvesting.  It’s too time consuming to pick out lots of worms.  I then finish digging the feeding hole, mounding up the castings & worms to the side.

I only recently became curious about how much castings I take out.  Now I keep a 5 gallon Harvest Bucket near the bin,  record the date in my feeding notebook when it’s full,  then replace it with an empty bucket.  I have lids marked Harvesting and Using, to distinguish the two.  The lids also serve to preserve moisture.

It’s really not important to track which zones get harvested, or when.  Following this method will let you take out finished castings on a regular basis.  And when feeding the bin, if you dig down to the bottom, making a fairly clean hole, you’ll keep everything circulating nicely.

One more thought about harvesting:  I’m amazed at how long I can go without removing castings - worms condense down food scraps tremendously.  But at some point you’ll want the payoff of this great soil amendment - or you’ll need to because the bin’s getting filled up to the top.

]]> http://compostingwithworms.net/harvesting-castings/feed/ http://compostingwithworms.net/cover-bin-surface-with-leaves/ http://compostingwithworms.net/cover-bin-surface-with-leaves/#comments Sun, 29 Mar 2009 19:03:23 +0000 admin http://compostingwithworms.net/?p=34 Surface Cover

By covering  the surface of your bin with some kind of moisture barrier - to slow evaporation - you’ll keep your bin at at a more optimal moisture level .  Cardboard sheets & old carpet serve this purpose, but I’ve found that a  1-2 inch layer of leaves works best.

The leaves decompose & are eaten by the worms. As food, this is a much preferable to the glue in corrugated cardboard or the chemicals in carpet.   And they love to hang out under this layer. During a hard rain, even though my bin is protected from the rain, many worms would crawl up onto the top edge of the bin.  Since I’ve added the leaf layer, they don’t do this nearly as much.