Q. Have you ever heard of adding vinegar or citric acid
when fertilizing plants in our area?
when fertilizing plants in our area?
A. Quite a few people have thought about it or tried it
but the positive impact on the soil is short-lived and is usually considered
not worth doing. Gardeners realize our soil is much more alkaline than the
ideal garden soil. Methods used to acidify soils are frequent gardening topics.
This includes the addition of acids such as acetic or vinegar and adding
sulfur.
but the positive impact on the soil is short-lived and is usually considered
not worth doing. Gardeners realize our soil is much more alkaline than the
ideal garden soil. Methods used to acidify soils are frequent gardening topics.
This includes the addition of acids such as acetic or vinegar and adding
sulfur.
 |
| Sulfur granules can sit on the surface of a desert soil for months or even years if it never comes in contact with water or is not ground finely. This does not help lower soil pH. |
Our
soils and our tap water from Lake Mead carry a lot of lime so the addition of
anything to the soil to make it more acidic is usually short-lived. A fairly effective long-term method for
improving our soil is the addition of compost or other sources of organic
matter that decompose, acidifying the soil as it does so.
soils and our tap water from Lake Mead carry a lot of lime so the addition of
anything to the soil to make it more acidic is usually short-lived. A fairly effective long-term method for
improving our soil is the addition of compost or other sources of organic
matter that decompose, acidifying the soil as it does so.
However,
adding weak acids to the soil is a short-term solution. How much acid to add to
a soil is another question altogether. Much of that depends on the chemistry of
the soil itself and varies from soil to soil.
adding weak acids to the soil is a short-term solution. How much acid to add to
a soil is another question altogether. Much of that depends on the chemistry of
the soil itself and varies from soil to soil.
Acidifying
water used for foliar applications of a pesticide or fertilizer is a different
story. This water should always be acidified to pH around 6.5 before adding the
pesticide or fertilizer. The easiest way to measure this pH is with litmus
paper, the type used for swimming pools or aquariums. Another option would be
to use distilled or reverse osmosis water instead.
water used for foliar applications of a pesticide or fertilizer is a different
story. This water should always be acidified to pH around 6.5 before adding the
pesticide or fertilizer. The easiest way to measure this pH is with litmus
paper, the type used for swimming pools or aquariums. Another option would be
to use distilled or reverse osmosis water instead.
Would you recommend using water softened by potassium chloride? Would it result in increasing the acidity of the soil?
Potassium chloride is far less damaging than sodium chloride or the normal water softening salt. Chlorides will still be a problem but much less of a problem. Keep the soil flushed to move the chlorides out of the root zone and keep it at a constant level so they don't accumulate. How much did you pay for the potassium salt and where did you get it? I heard water softening salts have really shot up in price.
And no it will not help in acidifying the soil. The chlorides will just end up paired up with cations like magnesium, potassium, sodium, calcium, etc.
I bought it for about $20 a bag at Lowes. I get the impression that using potassium softened water is not going to offer much improvement over plain old Colorado River water.
You are probably right. There are two problems with salts in soils and water. One is what is called general salinity. This will be true of any salt in the water. It is really a measure of total salts in the water of any kind. The second problem with salts is what is called specific ion effect. This is the damage that a specific salt can have on plants. There are three major salts that are toxic to plants all by themselves. These are sodium, boron and chlorides. Boron is really a bad one since it requires such a small amount to be toxic to plants. But on the other hand boron is also required by plants. It is one of the 16 or 17 essential elements. But boron is required plants in very small amounts. Once you pass this threshold, it then starts becoming toxic. Chlorine is in the same boat. It is required by plants but the level at which it becomes toxic is much higher than boron. Sodium is required by only a small number of plants and for most plants it is nonessential and so is just plain toxic. So your water softener, if plain old salt is used, exchanges Colorado river salts, the good ones and the bad ones, with sodium (and chlorides). Not good. But potassium chloride exchanges Colorado river salts, the good ones and the bad ones, for potassium and chlorides. So if you have to pick a salt to use on plants, potassium chloride salts are a far better choice than sodium chloride salt. So if you are just trying to reduce Colorado River salts you would have to use distilled or RO water which will remove salts. Otherwise you are just exchanging salts for salts.
By the way, the other two problems with salts in irrigation water and soils are the sulfates which contribute to concrete and steel corrosion and bicarbonates which can affect the chemistry of irrigation water.