Worm Castings or Vermicasts

Using worm castings, or more correctly vermicompost, as organic fertilizer adds more nutrients for your plants and in a plant available form.  Worm castings or vermicasts are just one component of what makes up vermicompost.

Here is how Wikipedia explains it:

Vermicompost is the product or process of composting utilizing various species of worms, usually red wigglers, white worms, and earthworms to create a heterogeneous mixture of decomposing vegetable or food waste, bedding materials, and vermicast. Vermicast, similarly known as worm castings, worm humus or worm manure, is the end-product of the breakdown of organic matter by a species of earthworm.[1] These castings have been shown to contain reduced levels of contaminants and a higher saturation of nutrients than do organic materials before vermicomposting. [2]

Here are some of the benefits of using vermicompost in your organic garden, per Wikipedia:

  • Improves its physical structure
  • Enriches soil with micro-organisms (adding enzymes such as phosphatase and cellulase)
  • Microbial activity in worm castings is 10 to 20 times higher than in the soil and organic matter that the worm ingests [27]
  • Attracts deep-burrowing earthworms already present in the soil
  • Improves water holding capacity[28]

It takes about 20 pounds to treat a 12′ x 20′ garden area.  Its fairly inexpensive, running between $1-$1.50/lb.

Prices accurate as of 5/9/2013

Make Your Own

For a standard size composting bin you will need two pounds of worms for every one pound of raw material you add.  The earthworms you will need (known as red wrigglers) do not go very deep underground so your pile or bin should be between 8-10 inches deep.

You may be tempted to go to your backyard and start digging up some worms, but you really should invest in the proper kind.  The worms in your backyard are not the recommended breed for composting.  You will need to buy worms that bear the name of red wriggler (also known as redworms) or brandling worms.  But, you should also be aware of their tolerance temperature range.

Redworms or brandling worms can be purchased from a bait shop, some local gardening centers or by mail order.  An average worm can eat its own weight in material in 24 hours; keep this in mind when you are determining the size of your compost bin and the amount of worms you will need.

With the rate at which the worms consume the food waste, the timeline of getting from raw organic material to mature compost is relatively short.  The same principle applies as for regular composting – you need a good mix of green food and brown food (this can be in the form of shredded newspaper).  The finished compost is known as worm castings, worm humus, worm manure, and worm compost.

You should also be aware of the temperature range that various types of worms can survive.  Nothing smells worse than a worm compost bin filled with dead worms!  So, take some time to find what type of worm would work best for your location.  This post is not intended to give you all the information needed to make your own worm compost bin, but rather to let you know what’s involved.  If you’re interested, here are some resources for you.



You can also purchase and download the Kindle version of The Complete Guide to Working with Worms: Using the Gardener’s Best Friend for Organic Gardening and Composting (Back to Basics) for $11.99.

Prices accurate as of 5/9/2013.