Let’s face it. Buying brand new potting soil for every tray of microgreens isn’t especially sustainable. Or cheap when each bag of soil is $20. However, it would be kind of difficult to screen out all the roots, hulls, and stems that end up in the soil after harvest. Not to mention, if there was any mold present, it would be exasperated by reusing the soil unless it was sanitized. And I’m not about to start throwing piles of potting soil in my oven. Luckily I have other uses for good soil.
I have found a solution that I can live with for now. Jason built me a bin out of t-posts and pallets with a removable door. I get one of my teenagers to carry my containers of used soil out to the bin. Then I let it sit. I’m not necessarily composting because I am not adding layers and paying attention to how hot it gets, but I want to let the majority of the green matter rot so that I am left with mostly just potting soil again.
Next, I move the soil to our new greenhouse to build up our beds. The plan is to add layers of my spent potting soil and compost, and eventually we will have soil that is the envy of everyone who gazes on its glory. Look for specialty greens like arugula and mustard this fall as our first crop with this reused soil.
Eventually I would like to be able to reuse this soil for the microgreens. It is going to take more careful planning and a dedicated area to carefully compost and sift. In fact, inspired by mom’s grant for Red Brick Farm’s new greenhouse, I am starting to look at grants to possibly help fund a more sustainable solution for me.