Here at Nuts & Bolts, nearly all of our production beds are formed by placing a thick layer of Wood Chips directly on top of the grass (and poison ivy), sometimes up to a foot thick, and then capping that mound of wood chip with some compost and topsoil. One of the most common questions that we get is “WHY ON EARTH WOULD YOU DO THAT!?”
Oftentimes people think that you should never put wood chips into your garden because it will suck all the nitrogen out of the soil and leave the plants stunted and sad. While there is some truth to this, it is far from the full story. In reality, building beds like this leads to more nutrient and water retention and availability; improved soil structure, aeration, and drainage; a more balanced soil microbiome which leads to reduced disease pressure; healthier plants; and a tasty crop of edible mushrooms! 😊🌱🍄
Let’s take a look at what really happens to these beds as the wood chips decompose.
You see, plant nutrients like nitrogen, phosphorus, and potassium are only available to plants when they are present as ions, that is to say, when they have a net electric charge. The atmosphere is roughly 70% nitrogen, but atmospheric nitrogen is electrically neutral and cannot be used by plants. While certain bacteria, like those in the Rhizobium genus, are capable of “fixing” that atmospheric nitrogen into ammonia, which has a positive charge and is usable by plants, all these ionic nutrients, nitrogen and other, need some way to be stored in the soil lest they wash away with the rain. That is where the wood chips come in.