Ever wonder what it takes to design a CSA crop plan? How do we ensure that there are at least 8 crops each week for the farmshare, with a revolving diversity of items and without too much excess left in the field. How are we able to deliver your favorite crops like lettuce and carrots on lots of weeks but fennel and kohlrabi not so much? The answers is a mix of fancy Excel algorithms, years of fine tuning and innate genius (okay, probably not that). We start by designing our theoretical ideal crop plan: We put crops on the y axis, dates on the x axis and then mark which crops we want to give each week. This requires knowing how early crops can conceivably be grown and harvested, how many weeks in a row a specific crop needs to be harvested, and a general idea of what makes a happy CSA customer. It’s also necessary to know how many weeks a crop can hold in the field before bolting or getting pithy, fibrous or bitter. Then we work backwards from each harvest date for each crop, subtracting the Days to Maturity in order to generate a planting date. This involves knowing approximately how many days it takes to mature a radish planted on Mar 17, or a zucchini transplanted on May 20, which is specific to every growing region. At this point we have a long list of hundreds of planting dates for over 40 different vegetable crops which we call our….Planting Calendar. Some crops like peppers only have one planting date while others like carrots or beets have six or seven different dates. (Since carrots only hold in the field 3 weeks we have to plant them every 3 weeks to have a constant supply). Some days we plant LOTS of crops and some days we plant none.
Okay, now that we have our timing figured out, let’s talk amounts or “bed feet.” To know how many bed feet (number of linear feet in a 5ft wide bed) of carrots we need to plant for, say, 2 weeks of CSA, it’s important to have a rough guess on what carrots yield. These figures can be looked up online, but it’s better to gather your own farm-specific data over several years of harvests based on your own soils, climate, pests, diseases, etc. At this point in our careers we know that broccoli yields about 1.3 heads per bed foot, and so we can be pretty certain that 77 bed feet will be enough for 100 CSA members. So, we then write 77 ft next to the corresponding broccoli date in our planting calendar. (This also assumes you already know the correct planting spacing with the bed, but that’s getting a little in the weeds). We then always overplant about 15%, assuming there will be some crop loss from disease, insect damage, bolting, bad germination, or a million other reasons.
Okay that’s an extremely simplified run-down of crop planning, but hopefully it gives you an idea of the planning required for every crop, every week of the season.
