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How the Dirt Maker 14 Composter Works

The Dirt Maker 14 flow-through worm bin is patterned after a proven design developed by the foremost-recognized earthworm expert Dr. Clive Edwards and his colleagues in the 1980s.

This is how it works. Newspaper is laid down on the 2" screen, and the worm bin is half filled with bedding. Then 15 lbs of earthworms are introduced. The worms are fed about 2 inches of food at a time. After about 3 months, the bin is full, the newspaper has decomposed, and the worms are near the top. Then a stainless steel bar is pulled across the bottom of the bin by a winch, causing vermicompost to fall through the screen. The material in the bin settles and bridges on the screen, making room for more food. When the bin fills up again, the bar is pulled the other direction, removing more vermicompost. From then on, the bar is winched once for every one or two feedings.

The biomass of worms will max out at 30-40 lbs in 3-4 months. At that point, this composter will be producing about 2 cubic feet of vermicompost per week when the bedding is within a productive temperature range. This range can be easily maintained with the average of day and night temperatures of the worm bin environment as low as 40ºF. The worm bin can be easily kept from overheating in an environment with the average of day and night temps as high as 90ºF.

The Dirt Maker 14 incorporates a design improvement not yet used by other manufacturers in flow-through worm bins this size or larger. The breaker bar rides about 3/8" above the screen instead of on it, greatly reducing wear on the screen.

Under most circumstances, a lid will not be necessary. In some cases, it's best to not cover the bin. In some other cases, laying a carpet remnant on the bedding is enough. In case a lid is needed though, we include functional handles and simple designs for inexpensively making one.

We suggest obtaining a compost thermometer. Our recommended bedding recipe requires some agricultural lime, a 2.2 cu ft bale of peat moss, and 8 cu ft of well aged manure or unfinished compost. By "unfinished" we mean that it's still somewhat sticky. Most homemade compost meets this requirement.

More details about this composter (including warranty information) are available in the owner's manual.