Compost is organic matter that has been decomposed and recycled as a fertilizer and soil amendment. At the simplest level, the process of composting simply requires making a heap of wetted organic matter (leaves, "green" food waste) and waiting for the materials to break down into humus after a period of weeks or months. Modern, methodical composting is a multi-step, closely monitored process with measured inputs of water, air, and carbon- and nitrogen-rich materials. The decomposition process is aided by shredding the plant matter, adding water and ensuring proper aeration by regularly turning the mixture. (Wikipedia)
Vermicast, also called worm castings, worm humus or worm manure, is the end-product of the breakdown of organic matter by an earthworm. These castings have been shown to contain reduced levels of contaminants and a higher saturation of nutrients than do organic materials before vermicomposting. (Wikipedia)
So the question then is what is best for you?
If you compost, your pile has to reach a high temperature for a long period of time to kill the harmful bacteria and break the organic material down. It can be hard or easy depending on you. The easiest way is to put a pile of leaves and grass clippings in the yard and let it decompose. You want to try to make sure there is a mixture of brown and green ingredients. Leaves are an easy brown, green can be celery coffee grounds, really anything from your kitchen except meat and dairy foods. This can be great for your garden but takes work and time. You have to decide if that is something you want to do or not.
Vermicomposting uses worm to perform the process of breaking organic material into basic plant nutrients with the end result being a much better product, the worm castings. The worms ingest and digest their surroundings so the harmful bacteria is killed and the beneficial bacteria in made better by the intestines of the worms. The worms cover their "poop" with a mucous layer that makes the worm castings time released.
Which is better? Compost or Castings??
Composting is great, and there is nothing wrong if that is all you choose to do, but worm castings are better than compost at improving the soils ability to retain water, drainage and aeration. It also helps improve the soils Ph level. They are also much higher in natural plant growth hormones. I am sure if you look at the NPK values of compost you will think that compost has won the game. Why would castings be better than compost, NPK is everything right? No, when castings consist of 20% of the soil, the plants germinate better, grow faster, bigger and produce more. The castings are very different than the compost and soil, they have a much higher percentage of humus. That helps the castings hold more water in and stay aerated. The humus also creates binging sites for micronutrients that normally would wash out during heavy rains. Castings include so many plant growth promoters, and increased levels in micronutrients which make them superior.
If you want to continue composting but want to make a better product adding castings will help add a larger biological diversity to the compost pile.
That would explain why the plants grow bigger and better with castings.
Our worms are fed a consistent diet of peat moss and "worm food". We offer many different sizes of bags and would love to help you succeed at making the best garden, lawn and plants you can have!!
I have added a picture showing the difference putting worm castings on your plant makes!!