How To Test pH Levels In Soil

A test is done when you want to know whether your soil is acidic, neutral or alkaline. Why does it matter? Most plants need a fairly neutral soil so they can retrieve all the nutrients from it that they require, but some are more fussy and may want it more acidic or alkaline.

Garden GearBy testing, you can determine if a garden location will be ideal for a new plant or if it should be amended first (to adjust the pH level as needed).

Many plants thrive in neutral (a pH reading of approximately 6.5 to 7.5) but there are some that require more acidic (below 7) or alkaline (above 7). The scale is from 0 (most acidic) to 14 (most alkaline).

For Accurate Results: Use clean tools and remove any debris from the garden surface then dig down about four inches to retrieve a sample. For potted plants, a couple of inches below the surface is fine.

Three Ways You Can Do It:

  • Use a meter, probe or kit: These vary in price and quality but one that’s around the $10 or $20 range is likely sufficient for the average gardener’s needs.
  • Quick & dirty DIY test: Not very specific but can give you an idea of what you’re working with and the supplies needed are likely in your pantry already.
  • Send out samples: This can be done free or at low cost using local government or horticultural facilities (universities, greenhouses, etc.).

Kits, Probes & Meters:

There are a few different types you can buy and the kits will come with instructions for using their particular product. Generally a test kit is used by pouring a bit of dirt in the supplied tube or container, add the provided tablet or powder, fill container with water and shake until powder or tablet is dissolved. After a few minutes the test will display a color that you will compare against the kit’s color chart to see the result.

Another option is a meter or probe that is either inserted directly into the ground or in a water & dirt slurry mix, these can provide near instant readings and display either a color code or number to indicate the content.

Quick & Dirty Method:

This won’t give you a specific reading, but it can give you an idea whether or not it’s acidic or alkaline.

  • Vinegar: Take a sample of dry dirt (about 1/4 cup), mix with distilled water to make a liquid “mud” and then start pouring household vinegar over top. If the mixture fizzes, it’s alkaline.
  • Baking soda: Mix dry dirt and distilled water as above then start sprinkling baking soda over top. If the mixture bubbles, it’s acidic.

If neither test produces a reaction, you have fairly neutral soil.

Do you remember way back in the day when grandpa would grab a handful of dirt on the farm and smell or taste it? It was the oldtimer’s method of determining the pH level…if it tasted or smelled sour, it was acidic and he knew then that it was time to add lime to increase the pH. Tasted or smelled sweet? That told him it was more alkaline.

Send Out Samples:

If it’s imperative that you know precisely what you’re dealing with, your best bet is to check with your local government agricultural office or university’s horticultural department, they’ll do the analysis or advise you where local gardeners can get their samples tested.

Quick Tips For Amending:

  • For more acidity (sourness), try adding sulfur, pine needles, cottonseed meal to lower pH.
  • For more alkaline (sweetness), try adding lime or wood ash to increase pH.

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    • Buffy

    Great info! I had never tested the soil but had trouble with keeping plants alive 🙁 But now I can discover if it is the soil, not me!! Thanks for GREAT information! This place is awesome!!

    • Bear

    I love the quick and dirty test tip!!!

    • Deborah

    I have never had a “green thumb” and testing methods can be too expensive-thanks for the GREAT TIPS-

    • Buck

    A general spoil test, which is more comprehensive than the meters is available through Umass for $10 –

    You need to send them about a cup sample and they can mail you results or send them by email –

      • Buck

      Oops – Soil test — hope it’s not a spoil test :-\

    • kris s

    does it matter what kind of vinegar? Is cider vinegar considered household vinegar the same as white wine vinegar is?

    • kari

    Just wanted to let you know that for amendments, alkaline soil has a high p.h. and acidic soil has a lower p.h. alkaline needs sulpher, acidic needs the ash.

    • SHARAD

    I want to buy Ph testing meter which directly insert in soil and provide instant reading.Where i get this thing.

    • Lora Notte

    I would like to say thank-you for the insight regarding soil. I for one am going to try at least two of the test,for comparison. The only question/s I would like to ask about is the actual outcome,please do not get me wrong,but every question a person could possibly have is thoroughly explained except if we are only pertaining to vegetable/fruit. And you say the neutral way is the way to success. How does this work with perinneals (sp)and other foilage and flowering perinneals? I had the worst year last year than any before. I don’t know what caused my flowerbed to literally just say “it’s not happening. I do not know if the sycada’s had anything to do with the plants just during or some other bug. If I spray dissolved dishwater soap directly on leafs’would or could it harm the plant? also what soil is better off if

      • Lucho Libre

      For the bugs on your flowers, plants and especially tomatoes use 300mg of aspirin with one liter of water. Spray on a daily basis till the bugs subside then around twice a week. Just watch that the leaves don’t change color. If the leaves change to a lighter shade stop using the sprayer. Use this method in the early morning or late afternoon when the sun is at its lowest.

    • Margaret

    Mix up a mixture of Epsom salts & water. Pour it around the plants and acid soil results.

    • Linda

    If I use pine cones as drainage in my pots, will that increase the acidity of the soil?

    • sean Snowden

    Pine needles are not good for acidity. Zone 4-5 above 6k ft asl clayey soil.

    • Dana

    Hello!! We are making raised garden beds this year and here in ok soil is “red dirt” clay compact!! We had soil brought in andi just tested it with baking soda and then vinegar , however I am out distilled water doesthat a major factor?? Thank u

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