Side Effects of Fertilizing with Worm Compost

One of the fun things about running a worm composting system is the (pleasant) surprises that greet us when we open the bin to add more kitchen scraps.  The innards from that cantaloupe we put in there three weeks ago?  All 800 seeds decided to sprout at the same time.  That apple core from two days ago?  Completely gone!  Herds of springtails stampeding across the open plains of finished castings!  Brushing off the top half-inch of castings to be greeted by a solid mass of happy, healthy Eisenia foetida.  (They look happy to us, anyway.)  It never gets old.

But the surprises don't stop there!  Lots of seeds that don't sprout in the worm bin proper are still viable.  We found that out last week, which was conveniently enough, a couple weeks after we mixed the crop of castings from over the winter into the square foot gardens on the decks.  Evidently, we had a very fertile cucumber in there.

All we planted was the broccoli, but we have a stochastically distributed crop of cucumbers and an apple tree as well!

In the past, most of the things that have sprouted from the worm castings have done so in the bin itself, and we haven't had to worry too much about using the vermicompost in the garden.  Don't get us wrong--plenty of things have sprouted--tomatoes, peppers, potatoes, melons, carrot tops, avocado pits, mulberry trees, and apple trees (the biggest one is almost three feet tall now!).  But these cukes caught us off guard.  We'll probably have to pull 'em to make room for the lettuce.

A quick search on the internets reveals that many other vermiculturers have had similar experiences--often with unwanted seeds that sprout from their seed-starting mix!  A few mentioned that one way to get around this problem is to expose the vermicompost to light for a few weeks before planting anything in them--that way all the seeds sprout that are going to, and it's possible to remove them without damaging the desired plants.  It seems that the most foolproof way would be to mix the vermicompost in with the dirt and expose the mixture to light for a few weeks.  Since we haven't planted anything but the broccoli yet, it turns out that this is pretty much exactly what we did, (although we did it accidentally), and it looks like it worked!  Now we just have to go pluck out all the cucumber seedlings.

Have you had any fun surprises from your worm bin?  Figured out a good way to get seeds out of the vermicompost?  Tell us about it in the comments section below!