Thursday, May 5, 2011

Farmer's Perspective: Planning Yields

[photo by Art Spiegel, via]

One of the first questions I am asked when proposing an edible garden or market farm program is, how much can you really grow in a small space? This question is not easy to answer, and how much the land can yield depends on many factors including climate, rainfall, soil fertility, management and crops planted. There are general rules of thumb for different crop types, such as mixed vegetables or orchard fruit that can guide planning. A more detailed approach is revealed in this post from Pablito at Terra Firma Farms. It’s a fascinating insight into the way one farm plans for one crop, and how that affects what its CSA customers receive each week. Detailed and technical, this post also points to the skill that a seasoned farmer can bring to planning an agricultural project. Hope you enjoy!
You may have noticed that some weeks the Large (or the Medium, or the Small) boxes get an item that the Medium (or the Large/and or  the Small) and/or Small (and/or the Large) boxes don't get.  Confused yet?  Welcome to our world.
Sometimes these decisions are deliberate, active choices on our part -- an effort to alternate items, for example. Just as often, though, the vegetables make the decisions for us.  Cauliflower and Broccoli are good examples.  Despite our efforts to plant them at regular intervals, the amount of crop they produce in a given week is determined by the weather.  A half acre of broccoli (a standard size planting for us) produces roughly 9000 heads over a three week period.  Ideally, this would translate into 3000 heads a week for three weeks.  The reality is usually something more like this:
        Week 1:  500 heads
        Week 2:  7000 heads
        Week 3:  2500 heads

With crops like these, we really don't know until the day of harvest exactly how much we are going to get.

Terra Firma currently delivers about 1400 CSA boxes each week, spread over 3 days.  Roughly 50% are Medium boxes, 30% are Small, and 20% Large.  Continuing with the broccoli example, we need at least 250 heads to do just the Large boxes.  If we have 500 heads, we can put it in just the Small boxes.  Once we have 1400 heads we can put a head in all the boxes.  If we get more than that in a single week, we can start to increase the amount in one or the other boxes:  2 heads in the Small and Medium, and 3 in the Large, for example (for a grand total of 3000 heads).  Sometimes we have enough extra that we have to sell it through another channel.

We always plan on growing enough of each crop to be able to put it in all the boxes.  It just doesn't always work out that we have enough for all the boxes the same week.  Which is why sometimes you might notice that you -- a Medium box subscriber -- didn't get an item that you want, but the Small (or Large) boxes did.  Or Vice versa. (And while) it is always our goal to match demand with supply and keep everyone as happy as possible. …in the end, we are growing fresh produce, not producing Iphones.

(excerpted from TerraFirma Farm newsletter, April 20, 2011)