In the back of my mind after four summers of growing vegetables in our sub irrigated planters (we began in 2007), I've wondered about the integrity of the potting mix. Could pathogens survive winter and affect the plants in subsequent years?
Earthbox says you can re-use potting mix for five growing seasons. We remove the mix from all our SIPs each fall and dry it out in the sun. The SIPs themselves get a swipe with a stiff brush...
...but stubborn attachments remain.
I was inspired after reading this post at Love Apple Farm (on growing potatoes in containers) to disinfect all our SIPs. I used their approach: a 10-to-1 water to bleach solution. If you click through, you'll see a happy worker twirling a potato bucket in its dilute bleach bath.
If life were so easy.
I spent parts of the last three days on the roof, scrubbing away every last scrap of anything that was attached to our grow buckets. Art set me up with a nice hot-water hose run from the laundry room (because our last frost date is May 15, we don't have the full watering set-up on the roof going yet) and a mortar mixing tub.
On the first day, I used rubber gloves and all kinds of bleach water got in and and made my hands raw. On the second day, I used packing tape to seal the gloves where they met the skin on my arms (nice look, Pippi).
Better, but today Art came home with these babies. Exceptional gloves.
I scrubbed everything, including the fill tubes, and let the sun do the drying.
In the middle of all this, Bruce emailed to say: as long as you're bleach-washing...we need 200 clean grower cups to transplant the eggplant, tomato, and peppers into. I was all over it. Disinfecting and reusing these cups year after year is a way to keep plastic out of the waste stream.
There they are. I'm glad it's done.
I'm still not sure about pathogens in potting mix. Love Apple Farm uses fresh mix every year to grow its container potatoes. That would be a deal-breaker for us. Let's hope all this bleach scrubbing leads to a glorious season of clean growing.