By now I’m sure you’ve heard all the buzz about adding biochar to your garden soil. But, I thought, how much difference could it really make? I’ve been working for years on the soil in my garden. It’s full of organic matter from homemade compost and carefully mulched. I fortify it with kelp and fish meal. The worms seem to love it.
In order to test it out, I planted ten seeds of ‘Black CoCo’ beans in each of two identical slightly raised 3′x3′ beds that held onions until July. I added compost, fish meal, kelp meal, and a small cupful of Sure Start to each bed. Then I added a quart of Soil Reef to only one of the beds. (Just for the record, I have no connection with Soil Reef, or it’s makers. And Soil Reef does contain compost and worm castings along with the biochar.)
In each of the beds 8 of the 10 seeds I planted germinated over a span of 12 days or so, The young plants did well in both beds, though the Soil Reef beans seemed perhaps a bit greener than the untreated bed. Then it got really hot and dry and I got very busy with work and couldn’t water nearly as much as I wanted to.
The smallest of the seedlings died and the others lost several of their leaves. In the regular bed, that is. Both plantings were lightly mulched with straw before germination and then more straw was added to retain moisture after the seedlings were up. This was not enough to sustain the beans planted in my usual soil mix very well through the drought. And the Soil Reef patch? A leaf or two was lost there as well, but the plants are bigger, greener, and much more vigorous.
These two pictures were both taken today. I left the toe of my shoe showing in both shots to give you a size reference. The leaves you see on the bottom left corner of the Soil Reef patch are sweet potatoes. And they present our second potentially confounding factor. Both bean patches are adjacent to a large rectangular sweet potato bed, in my standard soil mix. And it just so happens that the end of the sweet potato bed nearest the unhappy CoCo beans is not growing as well as the end near the happy, Soil Reef CoCo beans. There is also a large sunflower near the sad bean patch, which may be hindering the growth of both the beans and the sweet potatoes.
Even with the usual confounding factors found in the average urban garden, this experiment looks well worth repeating to me. What about you? Are you adding biochar? What sort of results have you had with it?