How much mulch ( ) should be used in the garden/containers; mixed in or spead on top? Thanks.
Adams County Colorado soil and fertility issues
By definition, mulch is something that is spread on the surface of the soil. For vegetable or annual flower gardens we recommend using a much that has a lower carbon to nitrogen ratio such as grass clippings or weed-free straw. For areas around trees, shrubs or perennials, woodchip much is a good choice. A layer of woodchips about 3 inches deep is recommended.
If you are thinking about adding organic matter to the soil as an amendment (mixing it in). We recommend adding 2-3 inches of plant based compost or 1 inch of manure annually and mixing it into your soil to a depth of at least 6 inches. Here are a couple factsheets with more information: http://www.ext.colostate.edu/pubs/garden/07235.html
I hope this helps, please let me know if you have any ofther questions.