Some questions continually resurface on the Inyo-Mono Master Gardener helpline. Hopefully your question is answered here!
Additional soil resources can be found on our website, but this is a good page to start with.
FAQs
Q: My plants are dying. What fertilizer is missing? A: It is exceedingly unusual to have such an intense nutrient deficiency in the garden that your plants will die. The most common consequence of a nutrient deficiency is reduced yield or smaller plants. It usually not noticed. In extreme cases, there are specific symptoms associated with specific mineral deficiencies. (See this fact sheet: Guide to Symptoms of Plant Nutrient Deficiences .) In our experience, a gardener concerned enough that they are reading a web resource on soil has probably over-fertilized. Reviewing data from soil test lab results, the rates of fertilizer home gardeners use far exceed agronomic recommendations. Nutrient deficiencies, when they occur, are usually related to pH problems instead. Locally that's usually iron which is unavailable in alkaline conditions.
Q: My plants are dying. I want my soil tested. What should I do? A: Most soil tests are designed to determine agronomic fertilizer application rates. They are of questionable diagnostic help in gardens. Lack of a nutrient so severe that it kills plants is rare. (See above.) Certainly a soil test will help you fertilize better, but in most cases — at least in our area — the problem is high pH or salts. We know which areas have those issues already. You probably don't need a test. If you think some toxin is in your soil, that is much more complicated to test for unless you have an idea of what it is. In that case, contact our helpline.
Q: How do I get a soil test? A: We have a page on soil testing. See that for more information. Most of our soils tend to sandy and low on nutrients until amended with compost or other organic matter. After that they tend to need a little phosphorus and sometimes sulfur. pH levels tend to be neutral as our young soils are fairly inert and lack clay. In other words, if you've been adding organic matter and maybe a fertilizer source, you probably don't need a test. But knowledge is power!
Q: My soil is clay. How to I fix that? A: Outside the low desert areas in southeast Inyo County, there are almost no heavy clay soils in the Eastern Sierra. A few locations have a mild clay layer. In any case, adding compost will improve your soil.
Q: My soil is very sandy. How do I fix that? A: Add compost. Start by working in 2-3" of compost. Add more annually.
Q: What kind of soil do I have? A: See our page on local soils. You can also find out about your native soil at this great website: SoilWeb.
Q: Where can I learn more about soil science? A: This site should provide a good foundation in garden soils.
Q: What is pH? A: pH is a measure of the acidity or alkalinity of a soil. 7 is neutral. Lower numbers are acidic, higher numbers are alkaline. Most garden plants like a range from slightly acidic to neutral. (6.2 to 7.5) Most soils in our high desert communities have soils from 6.8 to 8.5. In containers with soilless potting mixes, the pH will be a little lower, and your plants will be fine with that. If you are making your own soil mix from scratch and it uses peat moss, you will probably have to add limestone or dolomite. Do not adjust soil pH with wood ash or hydrated lime unless you really know what you're doing!
Q: Should I add gypsum to my soil? A: There are good reasons to add gypsum to some soils. It won't affect pH but it can help deal with sodium while providing calcium and sulfate ions. Most gardeners here will not need it if they're growing in their native soil, but we often see recommendations from labs calling for its addition in highly amended beds with a lot of organic matter, such as in raised beds. Contact the helpline if you need more information.
Q: What is the best fertilizer to use? A: There isn't one. Plants don't care about the source, only that they have access to the nutrients they need when they need them. If you are continually adding compost or organic material to your soil, you will probably be adding enough. Most retail products have recommendations on the container. You can follow those. If you are committed to finding an optimal fertilizer mixture, you will need a soil test. Virtually all soil tests we've seen from local gardeners who have already been fertilizing or adding compost regularly come back needing only nitrogen, and possibly sulfur. Add compost and you'll be good. You may need to add an additional nitrogen source, particularly to newer gardens. Watch your plants. Stunted plants that flower early indicate a potentially low N level. Plants that grow a lot of leaves and don't do much else, especially root crops, may be getting too much N.
Q: How do I know if I over-fertilized? A: Too much nitrogen will cause an abundance of vigorous, vegetative growth to the shoots: all leaves, no fruit or roots. Radishes will only grow leaves and not bulb up, for example. Ten-foot-tall tomatoes are a sign of too much N. Some crops do fine with excess fertilizer. If you got carried away, try planting sweet corn.
Q: How can I tell if I am under-fertilizing? A: This can be hard to tell. Pale, stunted plants are an obvious symptom. Usually a reduction in yield is the result. Noticing that yields are on the decline is a good sign, especially if you are practicing crop rotation and have a garden free of nematodes.
Q: Is fish emulsion OK to use? Sure! But keep in mind its odor may attract the attention of wildlife, especially racoons. 😊