Approaching the coast has a “last stop” feel to it. Vegetation becomes squat, the terrain low, eventually the coast appears – Next stop Portugal. Cape soil is incredibly sandy and thus very poor at holding nutrients – exactly the kind of place where biochar shines.
Co-owner Bob Wells has consulted with us for months now, so it was great to have an excuse to go out there and meet him and his business partner, Peter Hirst. And very cool as well to meet his home-made retort – the apparatus that creates biochar. The retort sits on a trailer, ready for adventure. In addition to making biochar, it is set up to heat their hoop house and make salt from water collected on the Cape.
Since you asked: Folks have been inquiring about the difference between biochar and charcoal. Differences in firing make a biochar burn much cleaner than a charcoal burn and yield a different end product. More on that and a great visual of how clean the burn is in this video of Peter Hirst firing a batch.
The 3 cubic yards of Rooflite donated by Skyland came in a bulk order delivered to Queens. Brooklyn Botanic Garden lent us their dump truck to fetch it. Thanks to Hort Director Mark Fisher for arranging that. BBG Arborist Chris Roddick signed on to drive and help load up.
Truck loaded, we headed back to Brooklyn for the mad scientist portion of the day. Test results on the Rooflite, biochar and compost came back from Logan Labs showing deficiencies in Copper, Zinc, Sulfur, Boron and Sodium. The quantities needed were very small and called for precise weighing. For that degree of accuracy we stopped on the way back from Queens at Oriental Pastry & Grocery on Atlantic Avenue to use their digital scale. (I’ve been going there since I was a kid). We headed to the back for some fresh Zatar and then got to weighing.
Following the weigh-in, we went to Brooklyn Botanic where compost tea was already brewing. The amendments were mixed thoroughly into the Rooflite and then the tea – 10 gallons of it – was applied undiluted. Chris below doing the tea drench.
Why the fuss? Soil chemistry and biology work in tandem. An element that’s completely lacking in the soil isn’t around to show up in plants or animals. But even if present, an element will not necessarily be plant-available without robust biology. (Check out mychorriza for an example of the amazing kinds of mutualism that happen under our feet daily).
This same process – amend, mix, inoculate – was applied to the biochar/compost mix. The mix drank up the tea like it was the end of a long week. Ten gallons seemed like a lot to apply to this quantity of material, but the mix drank it up so quickly that almost none of it even hit the pavement.
In the meantime, Green Zebra tomatoes are chugging along, as is Sweet Valentine lettuce. Carrots or beets will be direct sewn once the trials are installed and kale will follow later in the season. Tomatoes are way bigger now than in the photo!
We’re really looking forward to the first stage of the trial install this weekend. Looks like there will be an good turn out of really fun folks. See you there.