One of the most common questions we get at Terra Firma is “Do you rotate your crops?”. I understand why people ask the question, especially since the media so often uses the term “monoculture” when they are talking about agriculture. But for us, it’s roughly akin to asking the average person if they eat, sleep and breath.
Here’s a fact that might surprise you: almost all farmers in California rotate their annual crops. (Perennial crops are also known as “permanent crops”, and thus are not rotated except possibly over decades). It doesn’t get cold enough in California in the winter to kill plant diseases and pests in the winter. So planting the same crops in the same field every year is guaranteed to cause problems even for non-organic growers.
There are a number of factors that influence which crops farmers choose to rotate through their fields: climate suitability is the single most important one, followed by soil type and water availability. For example, it might be too warm or too cold grow certain crops. And even if it’s possible to grow those crops where you are located, you may not have good soil or available water.
Next comes economics: is the crop profitable? And how much specialized — and expensive — equipment does it require.
Many farmers in California have one crop that they specialize in that provides the majority of their income. Some have two. But crop rotation requires that a particular crop should only be grown in a certain field once every 3-4 years. That means you have to find two more crops to grow that you don’t (usually) lose money growing. If a farmer has a demand for, say 10 acres of a certain crop, they need to farm at least 40 acres in order to follow a good rotation.
At Terra Firma, we do not have a problem finding crops to rotate — we grow vegetables from numerous different families: Alliums (onions, garlic, leeks), Betas (beets, chard and spinach), Brassicas (broccoli, cabbage, kale), Carrots, Cucurbits (squash, cukes and melons), grasses (corn), Lettuce, Legumes (peas & beans), Solanum (tomatoes, peppers and potatoes), and Strawberries.
What we struggle with in our rotation is balancing the amounts of each crop. Our marketing demand for each is different, and some of our soils are not appropriate for all of them. Another challenge: many of the insect pests and diseases we deal with are not specific to one family and can affect a variety of crops. Labor is also a huge factor: we have to balance labor intensive crops with others that are less so.
A few examples? Fennel or bulb Anise grows great here in the fall and is very profitable for us. Unfortunately, demand for it is very limited. On the flip side, demand is very high for Cherry Tomatoes but they are not very profitable due to how slow they are to harvest.
Green Beans grow nicely here in early summer and then again in fall. They are also leguminous, which means they fix nitrogen from the air into the soil — providing fertilizer for the crop that follows them. They are not particularly profitable for us at our scale because they simply don’t produce very much income per acre. But they are a nice item to include in your CSA boxes.
Harvesting green beans by hand, however, is frustratingly slow. And they are very time-sensitive, as they must be picked within a few days of ripening or they will become overmature and begin forming seeds. You have to drop everything else you are doing — including harvesting more profitable crops — and pick them first. In economics terminology, this is a huge opportunity cost.
The Pixall 100 is a small-farm sized Green Bean harvester that was invented over 50 years ago to solve these problems. It strips the beans and leaves off the plants and then uses a large fan to vacuum up the leaves and shoot them out the side.
We bought a Pixall twenty years ago and have been using it successfully ever since. It allows us to grow green beans for our CSA without losing money or sacrificing much of our crew’s time, making them a reasonable “Rotation Crop” that doesn’t require us to do actual backflips to grow.