I’ve received a number of questions about what to do with clay soils to prevent them from turning into cement when they dry out. Also, I’ve received quite a few questions about how to turn sand into good garden soil. Here’s some information to help you decide what kind of soil you have and what to do about it.
Testing Your Soil
Testing your soil is the first step. Testing will tell you the levels of nitrogen, phosphorus, and potash, as well as the pH levels.
Start by taking a small soil sample every few yards throughout your garden. Small in this case means a handful. Take soil from the surface as well as down where the roots feed. You’re going to till the garden and mix up the surface soil with the soil deeper down, so you want a representative mix.
Mix all your samples together and take a jar full of the mix to a local garden center that provides a soil testing service. Or, if you want to test your own soil there are a number of soil test kits available. They are easy to use and give fair results.
Here’s a quick test to tell you if your soil is alkaline. Put a tablespoon of dry garden soil in a cup and add a tablespoon of white vinegar. Mix it up and have a listen. If you hear it fizzing you know your soil is alkaline and you should get it tested to see exactly what you need to balance it out.
If you cleared out pine trees to put in a garden spot, your soil is probably acidic. Testing will tell you for sure.
Balancing Your Soil
The results of your soil test should tell you exactly what shape your soil is in, and what you need to do to balance it out.
If you garden organically you will be able to choose ingredients for use in your compost so you end up with the perfect mix to improve your soil.
You can also add lime or whatever you need to adjust the pH levels of your soil. There are many choices to adjust pH. Compost will tend to lower the pH of alkaline soils and raise the pH of acidic soils. Sawdust and peat are useful to lower the pH if your soil is too alkaline. Wood ashes, oyster shell, bone meal and lime are good for raising the pH of acidic soils.
The next important characteristic of your soil is its structure.
Here’s a simple way to test. Use some of the soil you collected for your samples. Take a canning jar or similar clear jar with a lid and put in a cup of dry soil. Add a teaspoon of non-foaming dishwasher detergent. Fill two thirds of the jar with water and put on the lid. Shake thoroughly so soil and water are mixed. Set it aside someplace for a few days until it has settled.
The soil will separate into its component parts. The top layer will be clay. Silt will settle in the middle and sand will go to the bottom. Now you have a visual idea of the structure of your soil.
The target for good garden soil is 40 per cent sand, 40 per cent silt, and 20 per cent clay. By looking at the soil levels in the jar you can get a good idea of what you need to add to adjust the structure. You can use sand, along with organic material like peat or sawdust, to help break up clay soils. Sandy soils need lots of organic material like manure or compost.
If you have a large garden you may want to try a fall-planted cover crop to be tilled in come spring. The Agricultural Branch of your provincial government likely provides information on which crops to use for cover crops based on the results of your soil tests.
Don’t overlook old, moldy hay. If you know anyone who feeds hay to livestock, check with them in the spring for spoiled hay. It’s great to till in and decomposes quickly.
Manure is always a good addition to the soil. Fall is the best time to till manure into the garden soil so it gets a chance to break down over the winter. The freezing and thawing helps the process. Use well-rotted manure any time you can, but even fresh or partly-composted manure can go into the soil in the fall. Both the old hay and manure may give you lots of weeds if not composted completely, but it may be worth it if your soil is in need.
Once you have the right mix of nutrients and the correct soil structure all of your plants will be able to produce to their potential.
John Harmon owns and operates Tropicals North. Write to John at The Real Dirt, co 211 Wood St., Whitehorse, YT, Y1A 2E4 or contact him by E-mail: firstname.lastname@example.org.