Planting Macadamias

Question from Dave:
Hi Pat, your absolutely correct. Planting the beaumont macadamias with chicken manure was a mistake. The trees grow and burn and repeat again. I’m thinking of digging them up and replacing the soil around them. Alternately, is there a mineral that can be applied to neutralize or bind up the nitrogen?

Answer from Pat:
Chicken manure has more nitrogen in it than any other form of commonly-used manure. Guano from sea birds is strong also and can burn plants, but any manure can burn plants if not aged or even if is properly aged but used in too great a quantity. (See my Generic Fertilizer Chart for the approximate percentages of nitrogen, phosphorus and potassium in various manures and other organic amendments.)

Yes, there is a substance that could help you leach the salts and/or excess nitrogen out of the soil and that is soluble gypsum. If someone thinks they have over-fed a plant and as a result burned its roots and leaves the wise thing to do is apply soluble gypsum onto the ground according to package directions and then water it thoroughly into the ground.

Soluble gypsum has been treated with a chemical to make it soluble. Rock gypsum is not soluble or only slightly so. Organic gardeners, who are purists, believe in using rock gypsum instead of soluble gypsum because rock gypsum is “natural” and the other is made by a chemical process. The only problem with that belief is that rock gypsum only works if one can mix sufficient amounts of it into the soil for it to become a permanent ingredient in the soil. This is next to impossible unless you were using a concrete mixer to mix up a batch of fancy top soil from scratch. I feel that, even though I am an organic gardener there is no point in my recommending things that don’t work, so I am not a purist. I try to be practical. Soluble gypsum does no harm to garden soil, it is non-poisonous, and it does work. When applied to the ground and watered in, it dissolves and helps wash salts and excess fertilizer out of soil better than plain water would do. In the end, all of it will end up in the ground water or in the ocean, of course, which is on the side of the purists. Right? But simply by being alive and breathing and living in a house with electricity and traveling on airplanes to go places we are harming the planet. It seems to me all we can do is our best and try to be balanced and not fanatic about anything.

Additionally, I should tell you that only a few years ago bagged soluble gypsum was a white powder, and my book says to spread it onto the ground “as if a light snow has fallen.” Those instructions don’t make sense now since it appears that all of the manufacturers are now making gypsum in pelletized form, which looks more like hail than snow. You will just have to follow the package directions. Write and tell me if after you have spread it on the ground according to package directions it looks as if a light or heavy hail storm hit the ground. If so, I can say that when I revise my book next time for a new edition—which should be about eight years from now when the current edition is ten years old.