Well, first of all, let me say that it was free, and I like free stuff quite a bit. The folks at Soil Soup gave it to me in hopes that I would talk it up, and indeed I have. It’s easy to use, it’s a cool little bit of gear, and it’s gone down in price–last time I checked, a small version like this one was over $300, but now it’s down to $99. A much more reasonable price for a motorized bubbler, a bag of castings, a bottle of liquid nutrients, a mesh bag, and a plastic bucket.
The idea with compost tea is that if you take rich worm castings, which are full of beneficial microbes, and brew it in water, the microbial population will explode. You can then spray it directly on the leaves of plants, where all those good critters will do battle with the bad critters (I’m sorry this is all so technical, but bear with me), and the leaves will absorb nutrients, and your garden will be much stronger and healthier. Most compost tea involves some kind of nutrient solution that might include organic ingredients like liquid kelp, fish emulsion, and so forth, as well as molasses because the extra sugar gives the bacteria something to munch on.
So do you need to spend $99 on a brewer to make compost tea? Not necessarily, although it’s a fun thing to have around and if you think you’ll use it regularly, it might be worth the expense. I typically brew tea overnight, so a typical gardening routine might be to start a batch on Saturday morning and douse the garden on Sunday afternoon.
However, the low-budget way to approach this would be to take a scoop of worm castings or compost, mix it vigorously with water, and splash it around the garden. The key is to make sure it doesn’t sit around, un-aerated, and get anaerobic.
If you’re looking for some kind of middle ground, Gardens Alive has an interesting option–sort of a low-tech, no-electricity brewer that you shake and aerate with what looks like some kind of manual pump. I’m a little fuzzy on the details, but it’s only thirty bucks, and if you use this link and spend $40, you’ll get $20 off.
If you’ve got a big garden, you might consider a backpack sprayer to make this job easier, but for me, it’s kind of pleasant to walk around and bestow my compost upon my plants with a watering can. And do water the stuff down–you’re not likely to burn plants, but it doesn’t need to be applied full strength.
People also wonder whether the liquid that drains out of their worm bin is compost tea; the short answer is no. The liquid that drains out of your bin is a mixture of condensation from damp air or rain, the liquid component to the lettuce and whatever else you feed the worms, and–well–worm pee. It collects in the bottom of the bin and gets anaerobic. It might not be horrible for your plants, but it’s not the liquid gold you might think it is.
For more, check out the great information on Elaine Ingham’s SoilFoodWeb site.