Gardening: Gravel at bottom of pot DOES NOT improve drainage

I was reading Stuart Robertson's Tips on Container Gardening and realised that I'd been doing something very wrong. Layering different types of soil in the same pot. Uh oh!



Robertson writes in the book: "Never use a layer of gravel or small stones in the bottom of a small container, " that it's a common misconception that it improves drainage.

Robertson explains that if the soil has several layers, when water reaches a transition between layers, it slows down, and accumulates until it's heavy enough to break through that layer. The surprising part? Even if the water is flowing from a more dense layer to a less dense one, it still slows down! So, if you put a layer of stones at the bottom of your pot, you may find a lot of water accumulating right where the roots are growing.

And if you're wondering what the rest of the book is like, I thought it's extremely useful for newbie gardeners (like me). Rather than emphasising pretty pictures, he provides lots of useful tips and helpful diagrams.

And, incidentally, if you live in a flat, I've found that books on "Container Gardening" can be really helpful in giving you ideas and tips on growing and keeping your plants healthy.