Here I sit with my feet up and a nice cup of tea by my side while I listen to the rain….again. So it seems like a good time to talk about drainage.
If your land has a natural slope or your house is built on a hill, you probably know that the best way to deal with rain runoff is to have plantings that will absorb the water or at least send down deep roots to keep the soil from washing away. Here in Costa Rica, one of the best yard plants for that purpose is the maní, or perennial peanut. I know about the roots because I tried to dig some out to put in a shrub. Those roots are deep! Maní looks a bit like clover – solid green leaves and a small attractive yellow flower – and it can be cut like grass. I like it because it is a species native to South America. Since my land is quite hilly, I have been taking plugs of maní and transplanting them to help prevent erosion.
But it’s not just problems with drainage from running water. What we also have here is rain so intense that the lovely garden soil we worked so hard to build is washing away. Bummer. Even carefully planned and built raised beds are threatened by splash erosion. The rain is hitting the soil so hard that it creates craters right down to our seeds washing them away. Sometimes it even carries away our tender seedlings. Not good at all. But what to do?
All the solutions I have tried so far have involved a lot of work. Putting plastic up the sides of the raised beds and weighting it with rocks was only a little effective. I rejected putting boards on the slopes because they attract insects. And I once moved a board in the garden and found a rather long colorful snake hiding under it. Non-poisonous, but startling nevertheless. We watched each other for a while before it decided to vacate the area. (Had it been a large spider, well, the result would have been different. I don’t like spiders.)
So, what does work? I have now set things up so that the valleys between the beds all slope in one direction – an outlet under the fence (fence keeps the chickens out) that slopes away to the forest. I still have to go out and pull some of the soil back up to the mounds, but it helps.
What helps the most? Shade cloth. Not just for shade anymore. The rain pummels it, but the cloth slows it down and lets it drip softly on my plants. And it seems that a lot of the rain flows down the cloth itself and off into the trench around the raised beds. Some soil still slides off the beds but nowhere near as much as on the unprotected beds.
If you have a rainy season solution that works for you, let me know. Especially if it doesn’t involve too much work.