How to acidify irrigation water

There are certain plants that, unfortunately, cannot survive on calcareous water. And that is the type of water that we have in many parts of the world, for example, in the Mediterranean region. The best water for all plants is rainwater, but of course, not in all places does it rains enough to be able to use it throughout the year, so … if we cannot use tap water and neither can rainwater, ¿ what do we do? 

The answer is simpler than it seems because you just have to acidify it. Let’s see how to acidify irrigation water easily and quickly.

Plants that need acidic irrigation water

There are plants that need acidic water

There are many species that need this type of water. Such as the following:

  • Acer palmatum
  • Gardenia sp (all species)
  • Rhododendron sp (all species)
  • Pieris sp (all species)
  • Lagerstroemia sp (all species)
  • Hydrangea sp (all species)
  • Liquidambar sp (all species)

When in doubt, just look at the leaves of the plant. If they start to look chlorotic, that is, with very marked nerves, green in color, but all the rest of the leaf looks yellowish, it is because it urgently needs iron – it is usually the most common – or magnesium.

To prevent the problem from increasing, it is advisable to  use substrates with low pH (between 4 and 6, maximum 6.5), fertilize with fertilizers for acidophilic plants in spring and summer, and also acidify the irrigation water.

How to acidify irrigation water easily?

There are ways to know the pH of the water

If we have plants that need acidic water, it is not necessary to complicate much to give it. Actually, it will be enough to try any of these three tricks:

  1. One of them consists of adding the liquid of half a lemon to 1 liter of water , and stirring well to mix.
  2. The second is to  add a tablespoon of vinegar to 1 liter of water , and stir.
  3. The third is to fill a bucket or basin with water, let it sit overnight, and the next day use the water from the upper half , since it will not have as many heavy metals. Of course, this trick will only work if the tap water does not have a pH too high, but over 7. If you do not know what pH the water has, you can get pH strips or a digital meter.

What are the acids most used in agriculture to lower the pH of water?

There are some acids that serve to improve water quality. Here we are going to learn how to acidify irrigation water in agriculture. The addition of acids in the water has the main objective of correcting the pH of the water and being able to neutralize it . It also serves to be able to provide a greater amount of nutrients to the crops. At this concentration there is no damage to the crops and the solution is lowered to a pH of 5.5 to 6.5, that is, slightly acidic.

The most common acids used to learn how to acidify irrigation water are nitric, phosphoric, and sulfuric . The latter is more widely used for being the most economical, although the previous two are used in protected horticulture because they have the function of providing nutrients and acidifying the soil. To choose the acid to be used, the following characteristics must be taken into account: first of all, that it is an easy-to-use acid. Second that it is safe and third that it has a low cost than I can provide enough nutrients for plants.

To improve water quality, they are often used as raw material for the production of nitrogen fertilizers , although it also serves to lower the pH of the water. In the agrochemical market we can find different acid purities and concentrations. Industrial grade acid is normally used for agricultural use, while reagent grade is used for laboratory use.

High alkalinity water problems

Irrigation water must be adequate

We know that the quality of water for agricultural use is one of the most crucial aspects and that it affects the growth and development of vegetables. Currently, most of the water used in the sector must be given first in order to prevent possible problems that may arise in the soil or substrate. Most of the water used in agriculture is used for irrigation and fertigation. The direct problems related to water quality are usually the following: salinity, sodium, alkalinity and toxicity by specific ions .

All these limitations in water can be measured with some parameters that are related to water quality. These only following parameters: electrical conductivity, pH, concentration of potentially toxic elements and sodium adsorption ratio. Carbonates and bicarbonates are salts that are present in water and if the concentration is increased, the pH can also increase. It should be noted that the alkalinity and the pH of the water are two factors related to each other but they are not the same. The confusion between high pH and high alkalinity is mainly due to the fact that water is called as alkaline water as long as it has a pH higher than 7 . It is also called having high alkalinity if it has a high concentration of bases.

There are some risks when using highly alkaline water in irrigation systems without any prior treatment. There is a risk of clogging of the droppers because the bicarbonate bicarbonates precipitate the cations that are present in the water and form low solubility compounds such as calcium carbonate, calcium bicarbonate, sodium and magnesium. In addition, a too high pH in the water affects the availability of the nutrients that the plant needs such as zinc, iron and manganese .

I hope that with this information you can learn more about how to acidify the water and what it does so that you can water your plants with the irrigation water they need.

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