Old-school gardeners like me often brewed up a sort of compost tea by dumping a heap of whatever compost they had in a bucket of water and then sloshing it about where it seemed it might be needed. These days, commercial compost teas are made with carefully curated, standardized ingredients. The teas are then aerated by churning to “awaken” dormant microorganisms that should promote plant health. The result is often used as a foliar spray, which should work more quickly than root applications.
The theory of this is logical, but as far as I’ve been able to determine scientific trials are few and the results have been inconsistent. I suspect this is because there are so many variables involved. We’ll see if the science improves in coming years. Anecdotally, however, many gardeners swear by compost teas. I won a package of Bu’s Brew at a raffle at Annie’s Annuals last weekend, and this morning I gave it a go on things like citrus and roses. We’ll see how it does.
Here’s the scoop from Bu: