Note: I initially used the wrong chart in this post; anyone reading before 8am Monday saw a distribution by cost, not quantity.
Diversity on a farm can be measured in many ways. Particularly on market farms that like to grow heirloom varieties, the word is often taken to mean a wide selection of varieties, such as our 10+ kinds of garlic. This kind of diversity is primarily culinary and economic, allowing cooks to explore and use just the right kind of item, and farmers to reach niche markets. For example, customers can choose among our garlics to get varieties better suited for roasting, using raw, or making spicy food, a selection not possible at a grocery store. By exploring this kind of diversity, we can reach niche ethnic markets like the Russian customers who love to buy our big, black, hot radishes although no one else does, and thus improve our business.
However, it’s important not to confuse culinary diversity with biological diversity, as many customers and even farmers do. A stand offering, say, 30 kinds of tomatoes, 20 kinds of peppers, and 10 kinds of potatoes is culinarily diverse and thoroughly attractive, but all three of those items belong to the same biological family, Solanaceae. This means they are susceptible to the same pests, draw similar nutrients from the soil, and are otherwise comparable in the farm’s ecosystem. For organic and sustainable growers, who (should) rely on crop rotation to help break pest cycles and keep their soil & plants healthier, it’s very important not to rely too heavily on any one biological family. Farms who don’t pay close enough attention to these relationships may wonder why they have so many pest problems year after year despite how “diverse” their stands may look.
Managing this diversity, and an effective crop rotation, is one of the key aspects to developing our planting plants and seed order every year. The chart below presents a breakdown of our 2010 seed order by biological family:
The total varieties represented here number 181, not including other varieties for which we save seed ourselves or which are perrenial (coming back every year, like rhubarb).
We make a point of keeping these ratios balanced, even where a specific variety or family might be lucrative if we did more of it. There are three reasons for this: first, it reduces our need for pest control and soil management, a hidden benefit which is hard to quantify but is very important for true organic management. Second, it is not safe to assume that an item which is lucrative at one scale will remain lucrative at another. Making a good profit on 1,000 heads of garlic doesn’t mean we’ll make the same on 3,000, and we’re better off balancing a known quantity with something else. Third, maintaining this true diversity is a basic form of insurance. If we overplant just a few families (such as the ever-popular Solanaceae), we’re deeply reliant on proper weather and growing conditions for those families. A farm of mostly tomatoes and peppers will be wiped out by a bad year, though it may do better than us in a perfect year. We feel that maintaining a rational, conservative balance is better than a binge-or-bust farm plan.
Often, biological families are not intuitive. Tomatoes and potatoes do not, on the surface, seem to have anything in common. But nature works by very different rules than the visual spectrum, and a good gardener or farmer pays attention to how the world actually works. Growers who don’t consider this properly can end up having more pest problems than necessary, and feeling the need to correct this with methods they shouldn’t have to use. So the next time you’re planning a garden, or browsing a farm stand, take a moment to consider all the different ways diversity can be measured and considered.