DIY Test For Soil PH

David Trammel's picture

I'm going to have a much bigger garden from now on, and have access to a household's worth of compost (if I can get my sister out of the idea that compost attracts pests, lol) and two things I will now have access to are coffee grounds and wood ash. So I'm looking for ways to incorporate them into my Green Wizardry. It was this, which had me watch the following video:

"Benefits and Dangers of COFFEE GROUNDS and WOOD ASH in the Garden"

That though, is not what I want to talk about in this post. Instead, the vblogger of this video showed a quick and simple way to get a general idea of your garden's soil pH, using two jars of dirt, some vinegar, and some baking soda.

The steps are,

1) Collect samples of the dirt you want to test. Divide the sample into two equal amounts, then put them into the jars and cover with water.

2) Next, add some vinegar to one, and baking soda to the other. You may have to add quite a bit. In this case, he added nearly an amount of vinegar by volume and probably a quarter cup of baking soda.

3) Listen to the jars. If they fizz and generate bubbles, then that tells you the general pH of your soil. Lots of action from the vinegar one, the soil is high in alkaloids or the pH is low. Lots of action from the baking soda one, your soil is high in acid or the pH is high. If you get some fizz with both, then the soil is neutral. why this is, is that baking soda is a base, and vinegar an acid, and they react to their opposite.

4) Want to see what happens in high cases? The last video is them mixing both jars, lol.

Rather than spending money of fancy soil testing kits, or sending samples out, this is a quick way to get a general idea of the pH. A heavy action would then indicate you should get a professional test, but for general start of the season testing, this can save you some time and money.

Ken's picture

As a gardener from an area of plentiful rain and acidic soils, I take soil testing seriously. Any soil that is so acidic or so basic that it reacts madly to baking soda or vinegar is so out of whack that you'd be smart to garden elsewhere! And, that is good to suss out I suppose! On the other hand, if you are planning to amend your existing garden soils, it makes more sense to get a more accurate idea of your soil pH with cheap testing strips. $7 for 100 should last you a lifetime.
Now if there were some simple test for truly nasty contaminants that don't effect soil pH, that would be a good trick for Green Wizards to know considering the number of people that will be wanting/needing to garden in less than ideal circumstances and conditions.

lathechuck's picture

It's red when acid, and blue when alkaline. The trick would be to quantify just how acid/alkaline the soil is, based on titrating standard vinegar and/or baking soda solutions into the soil until the color flips.

By the way, "alkaloids" are chemical compounds, like caffeine, atropine, cocaine, and nicotine. Alkali in soil is the result of mineral salts (e.g. calcium hydroxide, sodium carbonate). "Alkaloid" is used improperly in step 3.