At lawn-seeds.com we try and cover all bases. We understand the gardening mind-set. You have an idea, a vision of the perfect lawn and garden… but nature sometimes throws a spanner in the works.
If you’ve ever struggled to grow the perfect lawn or wondered why certain plants thrive in one garden but not another, the answer might lie beneath your feet—in the pH of your soil. Understanding soil pH is key to creating an environment where your flora can flourish. Let’s dig into what soil pH means, how to measure it, and what to do when it’s not quite right for your gardening dreams.
What is pH?
In scientific terms, pH measures how acidic or alkaline a substance is, on a scale from 0 to 14. A pH of 7 is neutral, while numbers below 7 indicate acidity and those above 7 indicate alkalinity. The term stands for “potential of Hydrogen,” which relates to the concentration of hydrogen ions in a solution. Acidic substances have more hydrogen ions, while alkaline ones have fewer.
When it comes to soil, the pH determines the availability of nutrients to plants. Too high or too low, and your plants might struggle to absorb the essential elements they need, no matter how much fertiliser you throw at them.
Measuring pH in Soil
Testing your soil’s pH is surprisingly easy and can save you a lot of frustration. You can use:
- pH Test Kits: Available at most garden centres, these kits often include test tubes, a chemical solution, and a colour chart. Simply mix a soil sample with the solution and compare the colour change to the chart
- Electronic pH Meters: These provide a digital reading and are a great investment for regular gardeners
- DIY Methods: While less precise, adding vinegar to a soil sample can indicate alkalinity (it fizzes), while baking soda reacts to acidic soils
The Impact of High pH in Soil
High pH, or alkaline soil, can limit the availability of key nutrients like iron, manganese, and phosphorus. This often leads to yellowing leaves (a condition called chlorosis) and stunted growth in plants that prefer more acidic conditions. Alkaline soils are common in areas with chalk or limestone bedrock, such as parts of southern England.
The Impact of Low pH in Soil
Low pH, or acidic soil, can cause aluminium and manganese toxicity, harming plant roots and reducing their ability to take up water and nutrients. Acidic soils are often found in regions with high rainfall, where minerals are leached from the soil, such as parts of Scotland and Wales.
Adjusting pH Locally in a Garden
The good news is that you can alter soil pH to suit your needs:
To Raise pH (Make Soil Less Acidic): Add lime (calcium carbonate) in the form of powdered limestone or garden lime. It’s best applied in autumn to give it time to work into the soil.
To Lower pH (Make Soil More Acidic): Incorporate sulphur, aluminium sulphate, or organic materials like pine needles, composted leaves, or peat moss.
Plants and Grass That Prefer High pH
Alkaline-loving plants include lavender, clematis, and lilacs. In terms of grass, species like Kentucky Bluegrass and Perennial Ryegrass can tolerate mildly alkaline conditions, making them good choices for chalky soils.
Plants and Grass That Prefer Low pH
Acid-loving plants include rhododendrons, azaleas, blueberries, and heathers. Grasses such as Fine Fescues and Creeping Bentgrass thrive in slightly acidic to neutral soils, making them suitable for gardens with more rain-leached soil.
What to Do if Your Soil’s pH Isn’t Ideal
If your soil pH doesn’t match the needs of your desired plants, there are a few options:
- Adjust It: Amend the soil as needed with lime or sulphur
- Go Container Gardening: Use pots with customised soil to grow plants with specific needs
- Work With What You Have: Choose plants and grasses naturally suited to your soil type. Sometimes, going with the flow is easier than fighting nature
pH Shenanigans
Soil pH might seem like a small thing, but it has a big impact—much like deciding whether to drink tea with milk or without! Just as some of us can’t imagine life without a proper cuppa, your plants can’t thrive without the right pH. And remember, if all else fails, you can always call it a “wildflower meadow” and claim it’s intentional.