Crop Rotation: Keeping the Garden Moving and Healthy
One thing that is important to remember in order to maintain a successful garden is crop rotation.
Basically, you need to alternate the types of plants that you grow in a certain space. This helps keep the soil healthy since the same types of nutrients aren’t depleted. Just as important, crop rotation prevents the build up of pathogens that are linked to certain plants.
So how are we using this in the garden?
Well our biggest concerns are with our tomatoes and brassicas.
Tomatoes are susceptible to certain diseases, such as wilt fungus, blight and bacterial cankers, that can remain in the soil and affect other crops of the Solanaceae family (peppers, potatoes, eggplant etc.)The Brassica family includes kale, spinach, chard, broccoli. Again brassicas are rotated to maintain the soil and help limit pests and disease, such as club foot, in the next growing season. This is where it is important to keep a time frame in mind. If we were to plant a similar crop in the same bed of a previously diseased plant, it would also be susceptible. It may take up to four rotations before the disease has died out in the soil. Usually each cycle is about a year and therefore it is typical to wait three to four years between planting a similar crop in a bed.
Tomatoes and brassicas are known to be heavy feeders. This means that they feed heavily on the soil and uptake great amounts of nutrients. We keep a map of where we plant brassicas and tomatoes so that we can maintain the nutrients in the soil. A great way to do this is by planting crops that replenish nutrients. These kinds of crops, such as peas and dandelions, improve the soil and usually have root systems that pull up nutrients from deep in the soil.
Another method is by using cover crops. In the late fall we usually plant rye on certain beds that have had heavy feeders. This organic material will be tilled under and left to break down, adding matter and nutrients to the soil.
One thing we have seen in the garden is how tomatoes, which are perennials, come back every year in the beds that they have previously been planted in. Earlier this summer Francisco and I pulled out several tomato plants from beds that had previously housed Solanaceae crops, however they were quite persistent. There is one bed that is now overtaken by grape tomatoes (which were the star of our focaccia) and we decided we would leave them to see what would happen. Unfortunately, the plagues of previous Solanceae plants came back. The grape tomatoes are suffering from blight which had also infected the tomato plants that had previously grown in that bed.
Fran and I have learned that there isn’t a way to cheat the system. Fortunately we are still being overwhelmed with grape tomatoes!