When deciding what kind of worm bin to get and where to put it, consider both the worms’ needs and your own.
That may sound elementary, but I’ve learned from experience that there are a few basics you should think about in advance. Adjusting your thinking early will help determine later how successful and enjoyable a worm bin is for you.
To meet your needs, a home vermicomposting system will have to measure up to your expectations, provide a convenient method for converting organic waste to a usable end product, and satisfy your idea of suitable aesthetics. Potential end products are a supply of worms for fishing, worm castings for plants, or vermicompost for use in your garden. If you do use worms for fishing, it is important that you are aware of their proper disposal. (See chapter 5 for more information on worms as an invasive species.)
The effectiveness of your vermicomposting system will depend partly upon your expectations and partly upon your behavior. You can reasonably expect to bury a large portion of your biodegradable kitchen or food waste in a properly prepared worm bin, check it occasionally, make judgments about what must be done, then harvest worms and vermicompost or worm castings after a period of several months. You cannot expect to merely dump all the trash from your kitchen into a worm bin, add some worms, and come back in only two weeks to collect quantities of fine, dark worm castings to sprinkle on your houseplants. Either revise this unreasonable expectation to something more realistic, perhaps using the ideas below, or don’t even set up a system.
Vermicompost is a more general term than worm castings. A casting is manure, the material deposited from the anus after it has moved through the digestive tract of a worm. Vermicompost contains worm castings but also consists of partially decomposed bedding and organic waste with recognizable fragments of plants, food, and bedding. Worms of all ages, cocoons, and associated organisms may be found in vermicompost. If a worm bin is left untended for six months or so, worms will eat all of the bedding and organic waste, depositing castings as they do so. In time, they will have reingested the materials a number of times. Then the entire contents will have been fully converted to vermicast, which is completely worm-worked and reworked material with a fine, smooth texture. Vermicast is considered overworked and has probably lost nutrients. At that stage, since no food remains for the worms, most worms will die and be decomposed by the other organisms in the worm bin. The few worms that live will be small, inactive, and undernourished.
The difference between reasonable and unreasonable expectations has to do with the kind of food waste you bury, the environment you provide for the worms, the length of time you are willing to wait to observe changes, and the character of the end products. Success isn’t that difficult when you know what you want. Guidelines to help you make reasonable judgments about maintaining your worm bin effectively depend on your goals.
Goal: extra worms for fishing
Maintenance level: high
Some of you will want to produce more worms than you started with so that you have a ready supply for fishing. Expect to harvest your bin every two to three months, transfer worms to fresh bedding, and accept vermicompost that is less finished than if you were to leave the worms in their original bedding longer.
Producing more worms for fishing bait means having less finished vermicompost.
Goal: finished worm castings for plants
Maintenance level: low
Those who prefer to obtain castings in the most finished form have the advantage of extremely low maintenance. You will bury food waste in your worm bin over a four-month period, then leave it alone. You won’t have to feed or water the worms for the next few months, letting the entire culture proceed at its own pace. The worms will produce castings continuously as they eat the bedding and food waste. The disadvantage of this program is that as the proportion of castings increases, wastes that are toxic to the worms accumulate, and the environment for worms becomes less healthy. They get smaller and stop reproducing, and many die. As you wait for the worms to convert all the bedding and food waste to castings, you will have to deposit fresh batches of food waste elsewhere — perhaps in a compost pile or in a second worm bin.
In time, your worm bin will provide a quantity of fine castings to give you a homogeneous, nutrient-rich potting soil. If you choose this goal, you can alternate from one bin to another. Or you may have to purchase worms every fall when you set up your worm bin. This low-maintenance program enables you to vermicompost inside during the cold winter months, compost outside in the traditional manner when the weather warms, and have finished worm castings from your indoor worm bin sometime during summer.
A nickname for this maintenance approach might be “the lazy person’s technique.” However, if you use two bins, it’s actually a pretty efficient system; “the smart person’s technique” fits the situation better.
Worm castings enrich the soil for your garden or ordinary houseplants.
Goal: continuous worm supply plus vermicompost
Maintenance level: medium
Middle-of-the-roaders can opt for a program that requires just enough maintenance to keep the worms healthy. You will harvest fewer worm castings, but you should still have ample quantities of vermicompost to use on your houseplants and garden and enough worms to set up your bin again. About every four months, you will prepare fresh bedding and select one of several techniques for separating worms from vermicompost. These techniques are described in chapter 9.
It should be apparent that the effectiveness of your home vermicomposting system depends as much upon you as it depends upon the worms.
The convenience of your home vermicomposting system is directly related to its location. There are various possibilities. For some of you, locating your worm bin will depend considerably on what it looks like. A homemade bin may be practical but not necessarily beautiful. If it is a custom-made unit of laminated maple with sturdy legs on ball rollers and looks like a piece out of a Nieman Marcus catalog, you will want it where you can show it off most readily. Constructing your own worm bin is, of course, always an option; DIY instructions abound online, and classes may be offered at some organizations (see Resources for more details).
More realistically, before you decide where to locate your worm bin, (1) determine how large your unit must be to process your kitchen waste (see chapter 1 for more on this), (2) assess the space you have available, and (3) determine whether you want it to be merely functional and out of the way or the center of attention. To state this another way: How many guests do you want tramping through your basement? Or how many guests can deal with sitting on a window-seat worm bin in the dining room? From my experiences, I can guarantee you, until worm bins are common, almost everyone who visits is going to want to see yours!
Since food preparation is done in the kitchen, the most convenient location for a worm bin might be there, too. One of my friends has a worm bin on top of his dishwasher with a cutting board serving as a lid. When he is through chopping cabbage, celery, or whatever, he just slides the top back and scrapes the waste into his worm bin. You can’t beat that for convenience!
An outdoor patio off the kitchen is an excellent location for a home vermicomposting unit if it will be out of direct sun during the summer months. It is close to the origin of food waste, is near a water supply for maintaining proper moisture, and has plenty of ventilation. Just as you can expect to get dirt on the floor when you mix potting soils to repot plants, know that the periodic maintenance of separating worms from vermicompost can get messy. Doing it on the patio will keep the dirt outside. In climates where freezing temperatures are a problem, insulation and supplemental heat can keep the worms going. I describe some of these adaptations in chapter 9.
Apartment dwellers often have limited space. In warmer climates, many people living in apartments find that their balcony accommodates a worm bin and a few container plants. They like the appearance of the plants and feel good about doing something useful with their food waste. The plants give them a place to put the vermicompost produced in the worm bin.
A well-ventilated garage would be a satisfactory location for a worm bin if it blocks freezing temperatures in your production area. It also will provide shade during hot weather.
Locating a worm bin in a basement, if you have one, has the advantage of keeping it out of the way. If problems develop — there might be short-term odors or occasional fruit flies — the worm bin is not in the immediate living quarters. You might find it inconvenient to always go downstairs whenever you want to bury food waste, however. Basements do meet the worms’ temperature needs, being cooler in summer and rarely freezing in winter. Since they are out of sight and not in the way for most people, many worm bins, including mine, are located in a basement.
To make the worms happy, you’ll need to think about temperature, moisture, acidity, and ventilation. Equally as important, to make yourself happy, you’ll want to consider your expectations, sense of convenience, and aesthetic preferences.
You should be using the redworm, Eisenia fetida; the red tiger, E. andrei; or a combination of both. These are best for home composting, for reasons that I will discuss later (see Redworm). They feed most rapidly and convert waste best at temperatures between 59 and 77°F (15 and 25°C), with an optimal temperature of 77°F. They can work their way through food waste in a basement bin with temperatures as low as 50°F (10°C), but below this they reduce their feeding. Ultimately, these worms can survive in temperatures between 32 and 95°F (0 and 35°C). Below 39°F (3.9°C), cocoon production and development of young ceases.
Redworms have successfully weathered cold northern winters in pits dug into the ground that were covered with manure, straw, and leaves to provide heat, food, and insulation. The problem with an outdoor pit for winter food waste disposal is disturbing the protective snow covering to bury food waste. When the temperature drops to zero, such protection saves the worms, but your food waste also piles up!
Temperatures over 86°F (30°C) promote microbial activities that can consume oxygen that the worms need. The temperature in moist bedding is generally lower than the surrounding air because evaporation of moisture from the bedding in a well-ventilated place has a cooling effect. Locations that could get too hot include a poorly ventilated, overheated attic; outside under a hot sun; and in a greenhouse in higher elevations.
Maintaining moisture. All worms need moisture. They “breathe” through their skin, which must be moist for the exchange of air and the excretion of waste to take place. You can add water to dry bedding when necessary. Too much moisture, present as water standing in the bin, can reduce available oxygen and cause worms to “drown.” This can be a problem in plastic bins, a point I will discuss in more detail in chapter 9. Location is another factor with excess moisture. Place your worm bin where there is no danger of natural flooding, which could also drown the worms.
Maintaining acidity. Redworms can tolerate a fairly wide range of acidity in their environment, but slightly acid conditions are best. The 14-point scale for determining degree of acidity is called pH. The most acid reading would be pH 1; the most alkaline reading would be pH 14. Neutral is pH 7, meaning that the medium is neither acid nor alkaline. A wide range from pH 5 to pH 9 is suitable for redworms. In a worm bin with a pH of 4, you may find worms dying or trying to escape from the excessive acidity in their environment. Providing too much acidic food would be rather like pouring a bottle of vinegar into a worm bin — not a good idea! The most accurate method for testing the pH of your worm bin is to use a pH meter. Simply place the meter in at least three different places in the bin to check the pH level. If you don't have a meter, then use the smell test. If it smells bad, it might be a pH problem. I personally like using the meter because it is a simple, accurate, economical way to determine the pH.
Maintaining Ventilation. Worms use oxygen in their bodily processes, producing carbon dioxide, just as we do. It is important that you allow air to circulate around your container as a structural unit. Wrapping it in a plastic bag, for example, might be tidy, but the worms would quickly smother. For more on ventilation, see chapter 3.