Vegetables Gardening - Growing Organic Vegetables

There's a chart that's passed around aquaponics groups that shows various nutrients, and what the water pH needs to be in order to maximize the uptake of that nutrient.  Each nutrient has a range of pH that allows the plant to most easily absorb that nutrient.  When you look at the graph, it becomes obvious that the ideal pH for plant growth is around 6.5, since they mostly overlap around there.

Obviously there are exceptions to this.  Blueberries want more acid.  Some things want more alkaline.  But depending on what you're growing, if you had really alkaline water, does it make sense to collect the water in a tank, dose it with a (good) acid, and water with that?

Adding an acid to a base produces salt.  So this might not be a great idea.  Or it might be that the amount of salt is trivial.

What do you think?

brian

Brian Group:

Even more important than the pH of your water is the pH of your soil.  In the garden the pH is affected primarily by the amount of rainfall, and if an area receives more than 20" of rainfall annually the soil pH will be below 7 (acidic) - the more rainfall the lower the pH.  The solution to this is to add lime to the soil, because lime raises pH. 

 In low rainfall areas, with pH above 7, or alkaline, the calcium applied to the soil is gypsum, rather than lime, because it is pH neutral (equal parts lime and sulfur), and if pH continues to be high enough to cause a problem simply add sulfur to the soil, which lowers pH.

I don't think I would collect water in a tank and put sulfur in it, but that's a possibility IF you know what you're doing and you use proper amounts, so that you don't over-apply it.

I would suggest you find gypsum to use in your Pre-Plant Mix and check your soil pH occasionally, and perhaps add a little sulfur if needed.

Jim Kennard

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