If you want to get your valuable seeds off to a healthy and vibrant start, you might want to consider adding worm castings to either your seed starter mix or planting soil. For those not familiar with the terms "worm castings" or "vermicompost," it is basically that which is produced by the processing of waste products via composting worms. Worm castings are the more pure and refined product, whereas vermicompost contains a bit more of the decaying matter which has not been fully processed by the worms.
Because I practice both conventional (hot) composting and worm composting, I decided to put what I had read concerning the stated benefits to the test. I planted a number of seeds from heirloom tomatoes, peppers, greens, okra, and artichokes. In some, I used a standard quality seed starter mix, and in others, I added a 20% amount of worm castings from one of my worm bins. After about 10 days, there was a noticeable difference in both the amount of seeds which had germinated from the worm casting mix, and also the vitality of the seedlings. After this initial germination period, I continued comparing the vigor and health of the two groups of seedlings, and the results continued to be very obvious. Because some plant seeds are both expensive (or rare) and/or hard to germinate, worm castings should be of particular interest!
I have researched similar tests which have come to the same conclusion as my own, but when the concentration of the worm castings exceeded about 20%, the benefits started to decline. Therefore, this ratio seems optimal. There are theories that plant hormones in the worm compost (one of these being "auxin") aid in both the germination and later growth of the plant. The benefits from vermicompost do not just end with the seedling stage. These little "worm workers" (often called the intestines of the planet) also greatly increase the bio-availability of many plant nutrients, and it does not require much be added to the soil for these benefits to be realized.
Another exciting benefit has to do with the plant disease protection afforded by the abundant micro-organisms in vermicompost. For example, a number of trials have demonstrated control of verticillium in tomatoes. Additionally, these micro-organisms contribute chitinase which acts as a insecticide for your plants, and you can even make a compost tea which can also be used as a foliar application.
So why go through the trouble of producing worm compost for your plants? Well, it makes the best soil "that money can't buy." But, if you would rather not be bothered with vermicomposting, there are a number of garden centers and farmer's markets where you can purchase worm castings. However, due to varying production and handling practices, it may not end up being of the same quality and potency as that which you can produce yourself.
