Having a worm farm is a good way of producing nutrients for the garden by way of worm tea liquid fertiliser and worm castings which can add biomass for starting compost heaps or by being added directly the garden as a soil amendment.
One word of caution I'd give anyone starting out for their first time, raising worms. START OUT SMALL. Unless you've got access to the thrown out raw food (i.e.-veggies & fruits, no meat, no dairy, no garlic or onions, among other things) from a restaurant or grocery store, or you're cooking for a good sized family from scratch every night, chances are you won't have enough to feed them. At least, not without buying something in bulk....and then you might as well just skip the worms, and buy fertilizer. Being a single guy, with no other mouths to feed, I couldn't even keep up with a small amount of worms.....and if worms are happy, they won't be a small amount for long! Also, use careful consideration on where your worm farm is going to be physically located. If you're in one of the snow belt states, you'll have to bring it indoors at least part of the year (worms do best in 60 to 80 degrees Fahrenheit temps). If you're in a state that sees 100+ degrees, you'll have to equally consider where to keep them (a cool garage, or your basement, if you have one, should work). They DO make worm farm boxes that you can put right into your garden box (see link below), but again, those are going to work best in temperate climates. If you're prone to freezing weather, you'll have to consider how you'll keep it warm during those times (luckily, your worms don't like bright light, so covering it is definitely an option). DEFINITELY, DO YOUR HOMEWORK, before you start. Vermicomposting Made Easy: In-Bed Worm Composting
