Stackable Worm Bin

 Stacked Worm Bin Towers

Stackable worm bin towers are easy to use and were designed to overcome some of the hassles of traditional worm bins. Over time regular worm bins get water logged and messy making harvesting a dirty chore. Stacking worm bins use nesting trays that are stacked one upon the other in a vertical tower to avoid messy bins. Typically the tower is made up of between 5 and 8 trays. Because the system stacks vertically they also save space.

Stackable worm bins are widely available in stores and on the internet. They often come in a package deal including bins, worms, and bedding. These features make the stacking bin system extremely popular with home vermicomposters; especially among new worm farmers. However stackable systems are not only for the new worm farmer. Some worm farmers make their own stacking worm bins out of plastic bins or handmade wooden bins.

The tower of stacked trays sits upon a base unit that also serves as a moisture collection unit. Each tray has a series of holes, or mesh construction, on the bottom. This mesh lets worms migrate upward when the food and bedding in the lower tray has been converted to castings. The holes also allow for drainage of water or moisture leaking from the moisture in the bedding.

Stacking bins are fairly easy to set up and maintain. When you initially set up the first tray place a layer of fine fabric or newspaper on the bottom of the bin. This keeps fine particles of bedding from falling out and helps prevent your worms from dropping into the moisture collection unit in the base where they can drown.

Food, bedding, and worms are then placed in the tray and the cover is placed atop the tray. Your composting worms will do their job and eat both the bedding and food leaving behind castings. Eventually the first tray becomes filled with castings and runs out of food, making it a less desirable home for worms. At this time most of the worms will move up to the next bin on their own

Once the bottom tray is filled with castings another tray is prepared with bedding and food. For this and following trays the paper layer on the bottom is not needed, this would prevent the worms from moving up. Stack the fresh tray on top of the bottom tray. It won't take much time for the worms to figure out where the food is and they will migrate up to the new tray where the process of creating castings starts over. As new trays fill up with castings fresh trays are added above it.

As new trays are added the lower trays are left to dry. By the time a few trays are filled up the castings in the lower trays are ready for use. When used properly a stacked system can provide you with a continuous supply of worm castings once the first few trays are filled with castings.

There is some debate among users of stacked bin systems about how many working trays to use at once. A working tray contains worms.  Some worm farmers swear by keeping worms in only one working tray at a time. In other words they only have worms in one tray at a time; adding newly prepared trays only once the bedding and food in the working tray is converted to castings. Other worm farmers keep multiple active working trays at a time stacked upon one another. This system seems to work well for them.

We use multiple active trays in our stackable tray system. But we did learn a few lessons along the way. If you do want to use multiple working trays our best advice is to start slow and don't rush it. We recommend following the manufacturer’s instructions initially. That is to start with one tray containing about 1000 worms. Let that tray fully process, it will take about 3 months. Then set up your next tray and allow worms will migrate into it.

Go through the converted castings in the lower tray and sort out any cocoons and add them to your next tray. As your worms start to multiply you can choose to add more than one working tray at a time. We feel you should allow your worms to double in number before you add more than one working tray. If you add too many working trays too soon your worms may spread out between each tray not leaving enough worms to process the food and bedding.

In our system the worms tend to evenly distribute themselves among several working trays, we suspect this is nature’s way of regulating overcrowding in each tray. In fact worm farmers that raise bait worms intentionally keep the number of worms in each tray small. Again, shoot for around 1000 worms per tray.

Now that you know more about stacking worm bins see if they are right for you.

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