Compost better than rock dust as desert soil supplement

Question: My veggie plants were awesome last year, and my friends couldn't believe how good they were. I have been reading about adding rock dust to my veggie garden and other plants. What do you think about rock dust, and where is the best place to get it? And what kind of rock dust?

Rock dust is used in organic agriculture to replenish minerals that have been removed from the soils when cropping the soils (growing and removing vegetables and fruit). I do not know where to obtain rock dust in Las Vegas. Rock dust can vary among suppliers, depending on the type of rocks that have been crushed to make the dust.

If you are composting plant materials and kitchen scraps and adding this to your garden soil, then your need for rock dust should be fairly limited, particularly if the soil has not been used for many years. It is always a good idea to send in a soil sample to a reputable soil testing laboratory when first preparing it and then every few years to see where your soil is at in terms of mineral nutrients.

I tend to favor the addition of compost to our vegetable gardens rather than a regular application of minerals such as rock dust since our soils are so low in organic matter and the derivatives of organic matter, such as humic and fulvic acids. Compost tends to renew minerals in the soil in similar proportions to losses from the soil from harvesting.

Bob Morris is an associate professor with the University of Nevada Cooperative Extension. He can be reached at morrisr@unce.unr.edu or 257-5555.