How to Test Your Soil For PH
The best soil testing kits and services in the UK.
All About Soil pH Testing
Created by the team at DIY Gardening
Have you ever wondered why plants grown at nurseries and garden centres produce an abundance of flowers yet, once planted in your garden, they fade and rarely thrive?
Every plant, whether it’s a bedding plant, a shrub or a climber, will grow optimally if planted in soil within a specific pH range and is fed with specific feeds/fertilisers.
Sure, your plants may survive if grown in less optimal soil conditions, but to truly thrive, you’ll need to follow these simple steps:
- Research the plant online and note its preferred pH level.
- Test your soil with a pH testing kit or off-site service.
- Mix additives to your soil to boost or lower its pH level and add aeration, so it matches the plant’s requirements.
- Ensure plants are placed in the best location, taking into account sunlight requirements, soil drainage, aeration and exposure to wind.
Below you’ll find the best soil testing kits you can buy online and use at home.
We’ve also listed the ONLY off-site testing service we recommend; you can post samples of your soil and get detailed results in a week or two.
What is the Best pH Level For Garden Soil?
Most plants thrive in soil with a pH level of between 6 and 7, that’s slightly on the acidic side of neutral.
Some plants will prefer slightly more alkaline or more acidic soil.
For example; many heathers prefer soil around 5pH while mint, ginger and thyme thrive in soil with pH of up to 8.
pH is measured on a scale of 1 – 14.
1 is very acidic such as gastric acid.
7 is neutral, ie pure distilled water.
14 is very alkaline, for example; bleach.
1) Garden Tutor’s Soil Testing Strips
This soil testing kit comprises 100 test strips, each provides the user with a pH score between 3.5 and 9 which is perfect for UK gardens.
Each strip is manufactured especially for soil, so use them to check the pH levels of your flowerbeds, fruit and veg patches or the soil under your lawn.
You even get a detailed 16-page handbook explaining how to use the strips and how to interpret the results.
Garden Tutor’s kit is popular in the United States and is now sold in the UK.
For quick results, you can’t get much better than this soil testing kit.
2) Luster Leaf Soil Test
While Luster Leaf’s kit is a little more complicated to use than simple test strips, it does provide separate results for pH, Nitrogen, Phosphorous and Potash.
You’ll need to open the capsules, which can be a little fiddly; we dropped some of the powder when we used this product. We, therefore, recommend buying two kits as they’re relatively cheap and you’ll need more of the powder than is provided in just one pack.
We rate this soil testing kit 9/10 for results but 2/10 for awkwardness and lack of powder in each package; it’s not nearly enough for even a small garden.
3) Off-Site Soil Analysis
If you don’t want to test the soil yourself, you can send off soil samples to a laboratory, and you’ll get a detailed report within a couple of weeks.
We’ve used the Royal Horticultural Society’s soil analysis service before and highly recommend them.
They will test the soil sample for pH level, organic matter and amounts of Nitrogen, Potash and Phosphorous. Also, the report they send back will contain suggestions for improving the soil for vegetables, fruits, lawns and ornamental plants.
Prices are around £35 per sample.
4) Electronic Soil Testers
There are two types of electronic soil tester worth considering; moisture testers and all-in-one testers.
Moisture testers are very reliable and handy if you worried about watering sensitive plants too much or too little.
Our experience of all-in-one testers has been mixed; they work well at detecting light and moisture but don’t work so well at accurately recording pH levels.
Our advice: Use chemical and strip testers for pH levels and N,P and K levels, use electronic testers for moisture and light levels in the soil.
3-1 Soil Tester
This tester will reveal the light and moisture levels in the soil accurately. Use this device to gauge how much water you should use on plants or to test the ground soil – some plants thrive in wet, boggy soil while others hate it.
The manufacturers also claim that this testing device will reveal the soil’s pH levels but we found the results to be vague and inconsistent.
Before you place new plants in your garden, use this device to test the soil for moisture content. Some gardens naturally drain well while others hold more moisture, this isn’t always obvious at ground level.
With the results, you can choose the appropriate plants for your soil or add organic matter and fertilisers to change your soil’s makeup.
I Analysed Hundreds of Amazon Reviews: This Is What I Found
While I’ve used soil testing kits and the RHS’s service before, I decided to analyse all of the negative reviews I could find online.
This is what I found:
Reviews for the RHS testing service are hard to come by, but my experience was outstanding; the results were easy to read, and the advice helpful. My only complaint is the time it took to get the results back; 3 weeks is a long time to wait.
Most negatives reviews for the powder chemical testing kits were focused on the amount of chemicals in each vial. Many of the reviewers stated that the products worked well, but there wasn’t enough powder to repeat the tests.
There were very few negative reviews for the electronic moisture meter, and I know from experience that these devices and the light detectors are generally accurate.
The electronic ph meter is a different matter altogether, reviews were very much mixed, and many claimed that the ph reader was inaccurate or broken. If you’re buying this product solely for the ph reader, then you might be disappointed. I recommend sending off a sample of our soi for analysis; the results will be far more accurate.
Soil Testing FAQs
How Accurate Are Litmus pH Test Strips?
You can use pH testing strips to measure the acidity levels of the soil. You’ll need to mix the soil with distilled water first to get accurate results.
Do Electronic Soil Testing Devices Work?
We’ve found that electronic devices sold online and in garden centres work very well at measuring the moisture and light levels in the soil. The readings provided for pH levels are often inconsistent and don’t match the more reliable chemical test strips.
What is the Ideal pH Level for Soil?
Plants all require different pH levels so you’ll need to research the needs of the plants you intend to plant in your garden. Most plants thrive in soil that has a pH of between 6 and 7, although some plants prefer more acidic or slightly more alkaline soil.
What Happens if I Grow Plants in Soil That's Too Acidic or Alkaline?
A slightly acidic soil is just right for most plants. However, if the pH level is too high, the plants lose their ability to absorb nutrients. With poor nutrient uptake, leaves and stems may turn yellow and growth is stunted.
More From Daniel Woodley:
This guide to soil testing kits was created by Daniel Woodley here at DIY Gardening and was last updated on the 7th of June, 2021.
Discover more helpful hints and tips from Daniel over at the blog.
Daniel is a keen amateur gardener who also manages a large residential landscape in addition to his own mid-size garden.
He also enjoys growing vegetables and fruits as well as his herbaceous border and container garden.
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