Spade it in winter and it comes up in heavy, sticky clumps, like dirty Play-Dough; by summer the same ground has dried out and split open. That is clay soil, and it is worked with rather than against: organic conditioner, sand and mulch turned in, plus gravel beneath each planting hole, keep roots out of standing water.
Here is how to recognize the type of soil you have and what the options are to fix it.
This is easy to see by how it looks.
Indeed, clay soil is usually very compact, dense soil, that is quite sticky and when you spade it, it comes in large clumps that are hard to break down. It’s quite similar to dirty Play-Dough when moist.
Usually this soil is extremely heavy and damp in winter, and in summer it tends to become very dry and will even split or crack.
There are several different solutions that you can apply while spading your garden in fall or spring. You can try them one by one but it’s best to just do them all at once:
Each of the materials mentioned above tackles a different weakness of clay: microbial life, drainage, or sheer heaviness. Used together while you spade, they complement one another.
| Amendment | What it does | When to apply |
|---|---|---|
| Organic soil conditioner (manure and seaweed) | Raises microbial activity and fills the soil with humus | Autumn or spring, while spading |
| Sand and soil mix | Increases drainage and regulates water retention | Autumn or spring, while spading |
| Plant-based mulch, such as cocoa hulls | Makes the soil lighter and more fertile | Autumn or spring, mixed into the soil |
| Clay pebbles or gravel, 1¼ to 1½ inches (3 to 4 cm) | Drains the base of the hole so roots never sit in water | At planting time, before the plant goes in |
You can try them one at a time, but the fastest change comes from applying them all together.
You can provide for drainage when planting by layering 1¼ to 1½ inches (3 to 4 cm) of clay pebbles or gravel along the bottom of planting holes. This keeps the roots from wallowing in moisture.
