Do you remember Peter Staaterman, from Longnook Meadows Farm in Truro? He's the one, last fall, who grew the Dill's Giant Atlantic pumpkin that took first place at the Truro Ag Fair. Well, this spring, he's at it again. Only this time, he's growing giant asparagus:
I don't know if you can tell from the picture, but see those two little spears? Those are regular big-spear size, say, 1/2-inch in diameter. And that big guy? That's a solid inch across! Peter's been getting two or three stalks this enormous from almost every plant this season—a huge increase from last year.
The reason, he thinks, is an experiment he's been doing with manure and biochar. When Peter started farming his land in Truro, out toward Longnook, he had pretty poor soil. After a few failed attempts at growing vegetables, he knew he needed to do something to amend it, and so he got it tested and added the usual manure and compost. It worked pretty well. But this year, he also started adding biochar. We've talked about biochar once here—in connection with Bob Wells, who sells it at the Orleans farmers' market and uses it to grow fantastic blueberries—but it's still a relatively new thing. Basically, biochar is pure carbon made by burning any biomass—Peter uses wood—in the absence of oxygen. You need a special furnace for this called a retort, but once you get that, Peter says it's pretty easy. In fact, farmers in the Amazon came up with the process without any special equipment about two thousand years ago—that's how old of an idea it is.
So how does it help?
Well, mainly, on the Cape, it helps give the soil some structure. Peter kept adding manure to his asparagus patch, the way your supposed to, but because the soil is so sandy and well-drained here, the good bacteria in the manure that help digest it into compost and deliver the nutrients to the plants kept washing away, leaching out. It was frustrating. The biochar, Peter thinks, provides a home for these microbes—a repository of sorts—so that they stick around, and the asparagus is constantly fed. It's a pretty cool thing.
And the kicker is that unlike manure and other fertilizers, biochar doesn't break down. It will stay in Peter's soil for hundreds, even thousands of years—in other words, it's a permanent solution. All he needs to do now is keep adding a bit of manure, and he'll get a bumper crop of asparagus every spring.
My asparagus patch is still pretty young—I only planted it last spring—but I'm thinking of trying out Peter's idea, to try and get a jump start on things. I talked with Peter Hirst, who co-owns New England Biochar with Bob Wells, and in case you want to add a little biochar to your asparagus patch, too, here are his instructions. First of all, you can get it either by visiting their website and calling the company, or simply by showing up to the Orleans farmers' market and visiting Bob Wells at his stand. Peter Staaterman also sells a custom blend for the outer Cape—complete with biochar and other trace minerals that we lack, and that we need—at his farm stand, off of Longnook road in Truro. Wherever you get it, Hirst says you'll need about 40 pounds for an area that's 10' by 10'.
Then, once you get it home, you just mix it in with your soil the way you would any other amendment. I'm planning to add a little manure at the same time, so that I get all the microbial benefits. The ultimate goal is to make your soil 8 percent biochar by dry weight, but this is pretty tricky for a home gardener to calculate, so Hirst says go with about 1/4 pound per asparagus crown (or, if you're doing the rest of your garden, 1/2 pound per square foot) for starters, and take things from there.
Oh! and in case you're wondering whether you really want asparagus spears an inch in diameter—whether they'll still be tender and juicy and still taste good—they will, and you do. Peter's been selling his spears to the restaurant where I work, Blackfish, and they're tantalizingly good. We serve them over greens with a honey creme fraiche dressing and a local panko fried egg with the yolk still runny, and every plate I've cleared has been clean. I think it's one of those times when more really is better, if you know what I mean.