A new vermicomposting bin

Well progress can really be slow, but I think that as long as you can keep up on the day to day stuff and occasionally make some progress on the extra stuff, you will eventually get somewhere. I wanted to document my progress with my vermicomposting project. The garden has done reasonably well in a few aspects but it is still abysmal in others. (Half the corn didn't even come up, and what did is less than a foot high.)

Red Wigglers

Back in June, I found that a local farmers market had a organic farmer selling garden seedlings and red wiggler composting worms. Since my budget has dictated that I start out small, I decided against ordering a large amount of worms from an online vendor. There are a lot of different ideas for worm bins with different pros and cons, I think it is actually better to start with enough worms to see some real progress but not so many that you can't deal with them all. I chose to purchase one pound, which is approximately 1000 red wiggler worms, and costed about $30. With the shredded cardboard bedding, the worms came in two large yogurt containers.

Unique worm bin based on experienced vermicomposters

My primary inspiration for the bin came from multiple plans for bins at www.redwormcomposting.com. I didn't want to spend a lot of time and money building a wooden bin without understanding what the worms would need over time in my local climate, not to mention that a large wood bin would be very heavy. I decided to choose a plastic bin with handles and a lid that could be easily removed.

My other inspiration came from the commercial vermicomposting bins that are somewhat shallow and can stack up to six bins high. They have small holes at the bottom of each bin so that the worms can migrate upwards and the excess water can drain downwards. They have small vents in the sides for increased air circulation. Even though many bins will stack, it would be important that the bins would have some space between them even when stacked so that the material in the bin would not be compressed, crushing the contents of the lower bins. I would also be important to add enough compostable material that the upper bins would touch the top of the vermicompost in the bin directly below it, otherwise the worms would not be able to migrate upwards.

I decided to purchase two long, shallow, plastic bins at initially, the type that slides under beds for storing sweaters and other seasonal clothing. I would have preferred one that wasn't quite so long, but all of the other bins that I found to be this shallow were much too small, the size of a shoebox. I would have also preferred bins that were not clear because worms will avoid the light. (I found a dark shelf in my garage, so hopefully this won't be an issue. I added strips of cardboard around the sides to also help with the light problem.) The bottom bin I left as-is to allow it to collect any water that would drain out of the upper bins. It would also catch any worms that decided to escape from the upper one. The upper bin I started using a awl to poke holes through the plastic but I found that a drill with small bit was more effective. I drilled dozens of holes in the bottom, a single row of holes in the sides towards the top, and a number of holes in the lid for ventilation. 

For worm bedding I used a layer of well composted material from my outdoor compost bin (about four months old), shredded newspaper that I sent through a paper shredder, and finally some slightly composted kitchen waste that was starting to break down in a different compost bin (about a week or two). I made sure that each layer was moist before adding the worms to it. I finally added some damp cardboard that I tore with my hands. Over the next few weeks I found that the thicker cardboard was better than the newspaper for retaining moisture and acting as a mulch for everything below it. The worms wouldn't come all the way to the top unless it was damp. I also found that after a few days there was a lot of water that had condensed in the top bin. I initially left off the lid just a crack to eliminate the moisture but then I drilled in quite a few more holes in the lid to allow for better air flow. Every other week I would take soft vegetable or fruit trimmings and bury them in the worm bedding. I also added a sprinkling of water around the edges that tended to dry out quicker.

Initial Results

By the end of July, the compost, newspaper, and cardboard had all been nearly broken down, with a large amount of worm castings and new worms mixed throughout. The two small containers of worms had spread throughout the bin with a large amount of cocoons and juvenile worms as well. I'm curious the exact propagation amount, but I'm not prepared to sift through the entire bin to count. I knew that I would need to start another bin soon as a new home for the expanding worms.

By mid August, I purchased a third plastic bin that would fit inside the others. I prepared it like I did the second bin with the exception of the lid. Since the bins would fit inside each other, I didn't need to use the lid for the new bin at all. Instead I can just use the old lid that is already full of holes for air flow.

Next Experiment

Purposefully, I didn't put any of the red wigglers into the new top bin by hand. I'm hoping that my plan works and the worms will migrate through the holes into the upper bin. Of course there are a number of things that could go wrong: drilled holes too small, upper bin environment not acceptable, air gaps between top of compost and bottom of bin doesn't allow worms to reach holes in upper bin, and I'm sure that there could be others. If all goes well, I can check in a few weeks to find worms in the upper bin. I'm going to leave it there for about a month before I try to remove the worm castings from the lower one because I would rather that the cocoons would hatch and the juvenile worms would be able to migrate upwards, instead of being mixed in with the outdoor soil and lost as a resource for my vermicomposting experiments. I'm sure that I won't get them all, but I'm hoping that this approach will be more successful than the other techniques that I have read about by sorting through the bin by hand.

Still thinking and reading about vermicomposting

Life has a way of throwing a wrench into your plans. Not only has it snowed again this week, but my basement sump pump isn't working correctly (plugged / frozen discharge line) so my basement got flooded from the already saturated soil behind the house. It seems that all of my free time has been spent using a secondary portable sump pump and garden hose to pump out the root cellar and window wells several times a day. Evening activities with the kids for school or boy scouts (I'm a scout leader) also fills up my schedule. That doesn't mean that I haven't been thinking and dreaming about my worm bin project.

I found a great blog about vermicomposting at http://www.redwormcomposting.com/ which is also a good source for purchasing worms as long as you are looking for a large quantity. (A single pound of redworms is $35 while ten pounds is $180, only $18 per pound including shipping!) The best price that I could find locally was $25 per pound plus tax and driving one way about an hour. I have figured out that my little five gallon bucket bin works fine with a handful of earthworms but to consume the large amount of food scraps that our family of eight produces, we'll need about ten pounds of redworms and a more shallow bin with larger surface area. (Earthworms do fine in deeper bins, but don't thrive in this environment) I think that something this size would make a better fit as part of the outdoor landscape next to the garden, chickens, and rabbits. Besides, the resulting compost will be used in the garden anyway so that seems to be a natural fit. Once I figure out what kind of bin to make that will fit that criteria, I'll start building it and place my order for worms. (They have several great ideas for bins at this site too) I'm leaning towards a large wooden bin, but I want to research more about how it handles during hot, summer temperatures and if there are issues with ants or other critters getting into the bin. I'm hoping that it if set it into the ground with a styrofoam insulated lid, it will be protected enough to do well year round.

That said, it may be a few weeks before I can start on the worm bin. The weather forecast is looking good so a permanent solution to the basement flooding will preempt most other projects. That will be such a relief to get fixed once and for all!

How many composting worms do I need?

I need to figure out how many red wigglers composting worms I need to purchase for my new compost bin (yet to be built). I know that I could start these worms out in five gallon buckets, with holes in the bottoms for drainage, so I'm not worried about building the bin quite yet. Several sources confirm that a pound of red wigglers (about 1000 worms) will consume between 1/2 and 1 pound of food each day and turn that into castings. One pound of food scraps or worms are about the same in volume at about 2 cups. There are many sources that sell them in 1 lb increments.

Worms are going to be able to consume scraps that have been ground or broken up a lot easier than large chunks, but Anna at The Walden Effect has been experimenting with vermicomposting with food wastes from a local elementary school in her area and found that with nine pounds of worms, they were able to consume all 37 pounds of the whole food scraps (including meat) within five days. If she had equipment to grind up those scraps, it may have been even quicker. This equates to each pound of worms being able to consume 0.8 pounds of food, confirming the estimate of a pound of worms consuming 0.5 to 1 pound of food.

Food scraps are not the only thing to add to your worm bin. They need a supply of clean, moist bedding and grit or sand to help them grind their food (birds need grit too). I have tried using our paper shredder on newspaper and it works great. Non-glossy junk mail and cardboard would work well too. Mixing shredded paper in a bucket of water will shrink it much more than you might suspect, so having a large bag of shredded paper can save time from having to go back to get more. Don't forget to consider adding crushed leaves, grass clippings, and straw to the shredded paper. That type of bedding will take longer to break down, but the end result for your garden will be much better than just shredded paper which has a Carbon:Nitrogen ratio of 175:1.

What is not recommended to feed worms?

• Animal manure from cows, horses, or other farm animals should be composted or aged before adding to a worm bin.This high nitrogen source may start composting in the worm bin, elevating the temperatures, and "cook" your worms. Once the "heat" is taken out of the compost, worms do an excellent job at finishing that compost to make it more available for plants.
• The levels of bacteria and parasites present in cat, dog, and human manure manure would contaminate your garden produce and make its way into your food. It shouldn't be considered unless composted under high temperatures first. Expert composters don't want to lose this plentiful source of nitrogen, but personally, I have enough other sources of manure so I'm not going to risk it.
• High salt content would have a similar effect to your worms that it does to slugs. They are both get their body moisture from their very porous skin, so salt can kill in large quantities. If you see food in your bin that the worms are avoiding, this may be why.
• Large amounts of acidic food (citrus, coffee grounds) can throw off the pH of your bin and introduce mold and spoilage. Small amounts of mold are a natural part of decomposition and fine for worms but too much mold is an indication that the worms are not able to consume the food they are given (too much or wrong kinds).
• Oils, milk products, and meat (especially uncooked) can go rancid and attract local vermin (skunks, opossums, raccoons, in particular). Worms can handle them in small quantities, but you will need to make sure that their bin is secure. These animals would love to find a good source of food scraps and will likely consume a lot of your worms at the same time.
• Large, hard food scraps such as corn cobs, fruit pits, seeds, and thick fruit peelings are better off ground up or thrown to your traditional compost bin instead. Worms are not able to do anything with them until normal decomposition processes break them down into soft, small bits that they can deal with.

Anna has experimented with various levels of worm castings and found that although castings improve the fertility of soil significantly and increased levels of beneficial bacteria, you can have too much of a good thing. Soil made up of more than 20% castings doesn't have as much macronutrients as traditional compost but at this level, "plants germinate better, grow faster, and produce higher yields. ... Worm castings have much higher percentages of humus than either soil or compost, which helps the castings hold more water and stay aerated, while also providing binding sites for micronutrients that would otherwise wash out of soil during heavy rains.  The castings are also chock full of plant growth promoters like cytokinins and auxins, along with increased levels of micronutrients like calcium, magnesium, and sulfur.  Worm castings also host ten to twenty times as much microorganism activity as plain soil." (Thanks Anna!)

Something else to consider is how fast red wigglers reproduce. Several sources seem to confirm that this species of worms will reproduce quicker than your standard garden variety earthworm. Your population of red wigglers will double every three to four months in optimal conditions. Wow! So if you decide to purchase all that you need right now, you will need to think about selling off the extras (or feeding them to your chickens) in a few months. Since I have a lot of hungry chickens, I don't think that this will be a problem!

and watch our home food waste to determine how much food we can give to worms every day. Adding cooked foods, including meat, will make a difference in that calculation, but if included, will determine why type of bin needs to be purchased or constructed.

Using worms and black soldier flies in the garden

photo credit: blacksoldierflyblog.com

Last Spring I started hearing about black soldier flies (BSF) as a great resource for composting food waste (even better than worms) as well as a high-protein food source for poultry. I found the best site to learn about these insects at http://blacksoldierflyblog.com/ where I was able to find plans and videos for building my own bin out of a five-gallon paint bucket. Jerry is the site owner and designer of a commercially available BSF larvae bin (biopod), and is very happy to respond to questions that you may have about his designs or black soldier flies, in general. I was also able to order a batch of larvae from him, since these flies are not native to Utah. People who live in the Southern United States can bait their bin and expect to attract wild BSF flies to lay eggs and start colonizing their bin at no cost.

What I found after trying to raise my own BSF was that they consumed food waste quickly and in large amounts, just as it has been promised. I was hoping that after enough BSF reproduced, I could start a second BSF bin and start feeding them to my chickens. There are quite a few people commenting on the blog how much their chickens love to eat the larvae. Obviously they are very high in protein and a good supplement to their regular feed. Here is a video from YouTube showing what a small colony of BSF larvae can do to a fresh hamburger in five hours (I didn't have this many larvae, nor the wish to have them eat a perfectly fresh hamburger that I had just bought):

Unfortunately I didn't understand the reasons why BSF don't naturally thrive in the arid environment where I live. Although there are plenty of neighbors with horse and cow manure which the flies like as a food source and a good supply of food scraps that I left in the bin, I found that the larvae would mature, leave the bin, transform into adults with wings, and fly away. There were a few adults that flew back to lay eggs, but there weren't enough eggs to keep the whole colony going. (They look like wasps as adults, but they are harmless and only live long enough to breed and lay eggs.) I also read on the BSF blog from others living in cold climates how the larvae are difficult to keep alive during the winter. Despite their potential advantages, I abandoned my BSF plans last year.

This winter, I decided to see if I would have better success with earthworms that with the BSF larvae. I used the BSF bin that I created from two five-gallon buckets, and removed the extra pieces that the worms didn't need. (The inside bucket was drilled with a bunch of small holes so that excess water and "compost tea" would drain into the second bucket.) I used a paper shredder to fill the bucket half full of shredded newspaper which I then soaked in water. I bought a couple of containers of worms from Walmart (where they sell fishing equipment), just to try it out. The fifty worms have survived just fine in my garage, but they were not active enough to eat much of the food that I left for them. The larger scraps were not touched, but the smaller scraps were starting to be broken down. I tried moving the bucket to the laundry room where it was warmer, but my wife didn't appreciate it there. It is for a good cause, right? :-) For now, it is tucked away in the basement until I can find a better place. Being in a warmer place has encouraged the worms to be much more active.

photo credit: thewormdude.com

I'm hoping to get a larger bunch of worms that will be able to break down food scraps faster (before they spoil and get moldy) and to be able to use the worm castings in the garden. If some of the worms end up in the castings, it is just going to help the garden or provide a nice treat for the chickens. I'm thinking that the Canadian earthworms that I already have were good for this "test" but I would rather put my money towards the more productive worms used in traditional vermicomposting.  Red wigglers are much smaller and you can buy a pound of worms (about 1000) for around $25. This rate is obviously much cheaper than the ones that I bought as bait worms, but most places don't sell them in amounts smaller than a pound. There are many, many, places where you can order them online, but without knowing for sure, it is probably preferrable to find a place that will sell you a few different varieties in your order since some may be better suited to your location than others. (I'll let you know when I end up ordering my own red wigglers)