Lisa Wickland of Bellingham, Washington conducted experimental trials on various flowers and vegetables. The carrots below were grown in a mixture of soil and organic fertilizers. One bin of carrots served as the control, with 0% worm castings added as well as two additional bins with 10%  and 20% worm castings. The carrots grown in 20% worm castings had considerably greater growth rate than those grown without worm castings. The germination rate was also greater with the carrots grown in 10% and 20% worm castings than those lacking the worm castings.

left carrot (control) - 0% castings; center - 10% castings; right - 20% castings

(credit: Washington State University Whatcom County Extension. http://whatcom.wsu.edu/ag/compost/lisaexpcompost.htm)

Uses and General Application Rates
Potting mix: one part castings, one part sand, one part perlite or pumice, one part peat moss.
Seed starting: sprinkle a thin layer of castings in the bottom of the seed bed.
Vegetable plants: place a handful of castings in the bottom of the hole when transplanting from flats to the garden.
Compost tea: Suspend a bag of worm castings (breathable cloth bag or burlap) in chlorine free water for 7-10 days. Primary benefit is a supply of soluble nutrients and beneficial microbes, which can be used as liquid fertilizer. Use to water plants (not recommended as a foliar spray). For more information on compost teas visit the National Sustainable Agriculture Information Service’s Notes on Compost Teas at: http://www.attra.ncat.org/attra-pub/compost-tea-notes.html.

Excess moisture is more of a problem in plastic bins than in wooden bins. Wooden bins, especially plywood, tend to breathe better. On the flip side, though, wooden bins can dry out quickly if left uncovered.

Put simply, worms like a warm, moist and dark environment. If you get this right you will likely see one of the surest signs of a healthy worm bin: mating worms.

redworms mating

If you didn’t know better you would think that the two worms above had somehow gotten tangled up. In fact they are in the process of sexual reproduction. When they are finished, each will produce a lemon-shaped, grain-sized capsule containing between 3 and 7 hatchlings. In a few weeks these hatchlings will be ready to reproduce, and the cycle will repeat.

redworm capsules

When you first start composting with worms it is natural to want to inspect them every day, or several times a day, but doing will likely slow down the reproductive rate of your worms. The less you disturb your population, the more likely the worms will be able to find other mates and reproduce. This is the main reason why growers only harvest their bins once a week. So turn off the lights, put some Barry White on the stereo, and let nature take its course.

This winter during routine inspection of my indoor bins I found the tell-tale signs of a vole infestation: a network of shallow tunnels just below the surface of the bin. For a worm grower this is a serious problem that must be addressed immediately and aggressively. Mouse traps have limited usefulness, and sonic deterrents don’t live up to the bill.

My indoor worm farm was essentially an ecosystem out of balance. There was a steady supply of food for the voles and shelter from the harsh winter elements. The voles were thriving while the worms were quickly being destroyed. What was needed was a predator. Enter “Fang,” a feral barn cat that came from the Central Vermont Humane Society. Within one week of releasing Fang in the coop the voles were gone (except for the half eaten carcasses she left on the floor) and the worm populations quickly recoved.

I’ve always liked cats, but now I can understand why the Egyptians worshipped them.

Brent and LeAnna Alderman Sterste purchased a pound of red worms in the spring and were kind enough to send me a link to their blog, complete with pictures of their pre-school daughter reading to her new pets. Here’s the link:

A Child’s Guide to Vermicomposting

Thanks guys, you made my day.

Before any of you vermicomposter even THINK about starving your red worms, read this article from the December 2008 edition of BioCycle, written by Professor Clive Edwards from The Ohio State University Department of Entomology. If anyone deserves the title of Worm Guy, Worm Dude, or Worm Boss, it is Dr. Edwards.

Here’s the article (with permission from BioCycle Magazine):

Can Earthworms Harm The Planet?

I’d say Dr. Edwards gave vermicomposting critics a pretty good flogging.

KR

“Dear Kurt, I got the worms which were in a nice solid bunch, moving, and ready to go on the compost, a real 2 pounds. Thanks. Great. I have an outdoor composter which has been building up for over a year or more and it has a door at the bottom, which slides up. Before the worms, it seemed kind of solid and impenetrable, but now that the worms have been working for 3 or 4 weeks and when I slid the door up, it seemed that compost seemed to be falling out and I saw worms.

What I am writing about, though, is what happens when the cold weather starts. It doesn’t get all that cold, maybe freezing once with ice on the trees and wires, and snow sticking to the ground and plows necessary or it might not snow at all, but what happens with the worms in the cold weather? So I was thinking I better get something started in the basement, in a small way. I have a wooden box to start with, and a few worms, getting them from the sliding door spot, with the dirt. A start in a small way. My composter is like a barrel with a cover on it, and a small opening, and fresh stuff on it, so getting worms over to one side and getting the compost is not going to be easy like it would be with a large open box. So, my question is, what about the cold weather? Will the worms survive it? And, my composter has no bottom. Will the worms disappear into the ground? There is plenty of food for them on the top.

This email is a bit loose and long, and the questions, no doubt, typical. I look forward to your advice. Rod”

Rod,
I’m glad to hear things are going well and I appreciate the feedback.

Since you have a basement and are willing to compost there the solution to your problem would be to bring it all inside and compost indoors year-round. I compost and raise all my worms in my cellar and I wouldn’t do it any other way. You don’t have to worry about heat or cold or rodents digging into your piles, and it’s easy to get to it. I’m attaching some plans that you can use or modify as you see fit. Worm Bin Plans

All you really need, however, is a plywood box big enough to accomodate the food scraps that you generate on a weekly basis.

If you’d rather stick to the outdoor composter then you can do a few things to help maintain a good environment for the worms. Worms can survive temperatures in the 40s, but they go into survival mode and won’t eat or reproduce that much. You can pile hay bales around the composter and/or cover it up with leaves and keep it well fed to maintain a warm core temperature inside. I have overwintered worms in Vermont in a windrow piled high with leaves and they survived, but it’s not ideal for up north. The worms that I sent you are not soil dwellers so you don’t have to worry about them burrowing into the soil, and if you keep the composter warm enough and well fed they won’t have any reason to crawl.

Hope this helps. If you have any more questions just let me know.
Thanks and good luck.
Kurt

“Hi, kurt,
I bought some worms from you a few months ago. It’s going great! I wanted to ask your advice on the separating of the worms from the vermicompost/castings. Also, can the final product be stored for future use, or would you recommend that I just add it to my gardens now. Thank you!”

Hi Kate,

Glad to hear that things are going well! You’ve come to one of the most fun parts of vermicomposting–harvesting the worms.

There are many ways to do this but the best way is to let the worms do the work for you. Place a few large watermelon rinds face down on the top of your bin. Cover the bin and leave it alone for a few days. Come back and turn over the rinds and scoop up the worms and transfer them to a holding bin. Repeat these steps until very few worms come to the top. Then dump the castings, refill your bin with bedding and transfer the worms back to the bin.

Other methods include divide and dump, whereby you remove half your bin (worms and all) and dump it on your garden and fill the empty spot in your bin with new bedding. Your population will rebound in a month or two but if your goal is to grow more worms this is not the best option. A variation on this is to push all the compost to one side of the bin and fill the empty spot with food and cover. In a few weeks all the worms will have moved over to the side with the food and you can remove the compost from the other side and dump it on your garden.

Another popular method involves using the worm¢s aversion to light to your advantage. Dump the contents of your bin on a tarp on your floor or work table and make a number of cone-shaped piles on the tarp. Shine a bright light on the piles and move from one to the next, gently scraping off the top and sides and dumping the compost in buckets. As you work the piles the worms will crawl away from the light and after a few passes you will be left with small piles of worms that you can pick up and transfer to new bedding.

As for the castings, you can store them indefinitely. Best way to do this is to dry them first (spread them out on a tarp and let them air dry) then store them in a grain bag (available at any feed store for about 50 cents a bag). I usually screen my castings to remove large clumps, but if you aren’t fussy you can just use them as is. I’ve got a bag in my cellar that has been there for a few months and as far as a know there is no loss of microbial activity or nutrients.

Good luck and let me know if you have any other questions.
Kurt

P.S. if you want to see how growers separate worms from castings, here’s a pic of a commerical worm harvester.

harvester