All vegetables are sensitive to temperature changes over their lifespan, from “birth” through to harvest.  Seeds germinate more quickly when the soil is over 60 degrees, but will simply cook if the soil gets above 85 degrees.  Tomatoes ripen much slower when it’s cool then when it’s hot.
This time of year, Broccoli is the most temperature-sensitive crop we grow.  Cold temperatures can slow down the maturation of the broccoli heads, adding a month or more to the days-to-maturity of the crop.  If it’s too cold, for too long, it can stunt the plant and cause it to make tiny heads that are barely worth harvesting.
Broccoli heads start out the size of a quarter, and over a week or two, get bigger every day.  But at some point, they start to “open up”.  The individual florets begin to separate and prepare to begin making flowers.  At this point, the flavor of the broccoli gets spicy and the texture becomes more rubbery.
Harvesting broccoli is a combination of art and science, trying to let the heads get as big as possible without losing quality.  When it’s warmer, the heads can double in size in two days.  But they can also go from perfect to overripe in two days.  So making the right harvesting decisions about when to harvest, as well as which individual heads to pick –can have a major impact on the quantity and quality of the broccoli.  We have a dedicated crew of broccoli-harvesting experts — Los Brocoleros — that picks the crop all winter, learning the nuances of its growth over four or five months.
When it’s cold and foggy as it has been most of January, the heads grow incredibly slowly.  Instead of harvesting broccoli every other day, we’ve been picking it once a week.  And the heads will start opening up before getting very large, so we’ve had to pick them smaller, as you likely noticed in your boxes.  The net effect is to greatly the overall quantity we harvest and means we don’t have enough for all your boxes.  In the broader world, it means the price of organic broccoli at the supermarket has soared since New Year’s.
Over the past weekend, we had a slow but signficant warm up in both day and nighttime temperatures of about 10 degrees.  The broccoli responded literally overnight, and on Monday morning we harvested twice as much broccoli as we did all last week — from the same size field.
With a stretch of warm weather in front of us, we expect Los Brocoleros to have a busy couple of weeks harvesting lots of nice sized broccoli for you.  And they and all the rest of us at Terra Firma are looking forward to getting a break from the cold, damp and mud for a bit.