Outdoor Worm Farming Systems – Part III – Beds and Bins

This is our final week covering the topic of outdoor worm farming systems.

For the last two weeks we have been looking at outdoor systems that don’t require any sort of physical structure. This week we will finally be talking about the structured systems – the outdoor bins and beds.

There are of course plenty of other sub-topics we could cover (relating to outdoor vermicomposting systems) over the next few weeks, but I definitely think it’s time to move on after this week’s edition – our next major topic is both important and interesting (if I do say so myself), so I don’t think too many people will be offended. :-)

As we’ve seen, there are a number of options available if one is looking for a really inexpensive, ‘low-tech’ type of outdoor worm farming system – especially when an abundance of space, and some heavy machinery (tractors etc) are available for use. These systems are not without their limitations however, and housing our worms in some sort of structure can certainly offer some advantages.

The main advantage of course, is protection – both from pests/predators and from climatic conditions. Even a thin wall between your worms and the outside world can make a significant difference in terms of keeping them safe and your system operating smoothly. The structure of a bin/bed can also really help to conserve space, since larger volumes of bedding and worms be contained per sq ft.

When it comes down to it, it’s all about maintaining as much control over the vermicomposting process as we possibly can – something that is especially important when operating a worm farming business, and which can be a major challenge for those located in areas with highly variable (and unpredictable) climatic conditions.

When using outdoor windrows and in-ground systems we generally give up some of this control, providing Mother Nature with a greater opportunity to dictate the success of our worm farming enterprise.

Typically, outdoor worm beds and bins will cost more money to construct than our previously discussed ‘low-tech’ options, but they certainly don’t need to break the bank – especially if one is able to secure a supply of used or reclaimed building materials.

In its most basic form, a worm bed could simply consist of four walls sitting directly on the ground (similar in appearance to a raised bed garden). While the walls would potentially offer SOME protection, the only real difference between this and a windrow is that it could hold the same volume of material within a smaller area. Adding some sort of lid to a system like this would make a huge difference in terms of shielding the worms from hot/wet weather, and attacks from predators (such as birds), but might not be a feasible option with larger beds.

With a bed that is open to (and makes direct contact with) the soil, you run the risk of having invaders – such as moles – accessing the system from below. If you live in an area where moles are present, it would be wise to use multiple layers of thick landscape fabric, or something comparable, as a bottom for your system to prevent easy entry.

In tropical and sub tropical zones, direct contact with the soil could very well mean easier access for land planarians – which can reportedly wipe out an entire bed of worms in a matter of days or weeks. As we discussed in a previous newsletter, laying down some sort of concrete pad, or better yet, an entire enclosure for your beds will obviously make a big difference – but this also may not be something you can afford to do initially.

One possible alternate solution is to raise your beds completely off the ground, by constructing actual legs, or by simply letting the system rest on cider blocks or some other supports. A floor will of course be required as well, but it doesn’t necessarily need to be a solid structure.

In fact, the use of a heavy grate or even well-strung weed whipper cord (more on that in  minute) could greatly assist anyone who is interested in harvesting worm castings, since it will be quite easy to access and loosen the material from below. You will in essence be creating your own flow-through bed.

The idea of creating a flow-through floor using a cord actually comes from the ‘OSCR’ (‘Oregon Soil Corporation Reactor’) vermicomposting system. For those of you unfamiliar with the name, this is a mid-size DIY flow-through bin (with building plans available from Oregon Soil Corporation and Vermico, by the way). The bottom grate consists of weed whipper cord that’s been woven back and forth from front to back.

This is actually a great system for anyone who is thinking about getting into worm farming, and wants to focus on castings production. The total cost of building this unit (estimated by the authors of the plans) is only ~$150 USD – although now, it might be more like $200 (since the plans were written quite some time ago). Aside from the advantage offered by the flow-through design itself, the OSCR also incorporates insulated walls and heating coils to help keep the system active during cold weather.

Speaking of cold weather…

Likely the greatest limiting factor for ANY outdoor system is climate. There are certainly some regions that have a near ‘perfect’ climate for worm farming, but for the rest of us, additional measures will likely need to be taken in order to keep our beds working well outside.

Winter cold is likely the greatest climatic hurdle, since it can effectively bring the activity (worm growth / castings production etc) within our beds to a grinding halt – or worse still – completely wipe out our worm population.

Winterizing worm beds is an entire topic unto itself, so I can’t say much more about it here, but I have included a related question in our short answer section so that we can spend a little more time on it.

As mentioned, next week we will be moving on to entirely different topic; something I’m sure a LOT of people are interested in – worm castings!

Should be fun!

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