Broccoli is a mainstay of Terra Firma’s CSA program and thus of our farm. We start transplanting it in early August and continue until about Halloween, just a few weeks after we normally begin harvesting it. Harvest lasts through winter and normally concludes sometime in March.

If you pay attention to the broccoli in your boxes, you may have noticed that it changes over the course of this six month period. The heads look different, changing color a bit and getting bigger or smaller. Sometimes the stems are short and fat; other times they are long and skinny. This is due not to the crop variety — we grow just two kinds of broccoli — but rather the conditions the crop is experiencing.

Just about all the broccoli we grow is planted into and spends much of its life in a hot, sunny and dry environment only to end up in a cloudy, cold and wet one. The changes you see in the edible part of the plant are its responses to these changes.

Thanks to its adaptability, broccoli is one of our most reliable winter crops. But it’s not indestructible. Too much heat in the fall can ruin it, as can freezing temperatures below 28 or continuous rain just before harvest. We lost one planting this winter due to a combination of very cold and very wet weather.

Right now we are harvesting several plantings of broccoli that boycotted the cold and wet conditions in January and waited until the sun came out to start making heads. As result, those heads are smaller and paler, with a longer stem. Please see my note below about the culinary value of those stems.

The health benefits of broccoli have been known for decades, not just the vitamin and fiber but cancer-preventing compounds. But it’s only been recently that its environmental benefits have been explored. As recently as ten years ago, farmers (and gardeners) were told that broccoli required a large amount of fertilizer — primarily nitrogen. “Everyone” knew it was a “heavy feeder”.

Nothing could be farther from the truth. I remember walking through a Terra Firma tomato field with the local farm advisor and seeing a sharp delineation between one half of the field where the plants were much bigger and healthier. We had grown broccoli in that part of the field just before planting the tomatoes.

The farm advisor was speculating that the residue from the broccoli had suppressed soilborne disease, thanks to the same sulfur-based compounds that help prevent cancer in humans. While that might have been true, there was also something else going on.

Research has now determined that broccoli plants can “mine” the soil they grow in to access nutrients that other crops — like tomatoes — can’t get. A new study shows that the roots can bring up nitrogen from at least four feet down in the soil — 3 feet deeper than previous assumptions. That nitrogen, left over from previous years, would otherwise end up reaching the groundwater. Farm advisors are now recommending that crops grown following broccoli need almost no fertilizer.

Given that nitrate pollution of groundwater is a significant environmental problem, this makes broccoli a legitimate ecological hero. And by eating broccoli, you are playing a critical role in supporting farmers who grow it.

So eat more broccoli, for your health and the health of the planet!