Tuesday, March 10, 2009

The Balcony Bosque

I’ve had good luck composting cured bokashi in my small bit of unshared outdoor space, but it occurred to me that my space isn’t exactly standard-issue--even in Austin, not everyone chooses to build a balcony around a tree rather than cut it down. (Though it does seem to be more common here than elsewhere.) And the tree’s not the only bit of nature to be found just outside my door; for most of the year I have geckos and anole, the occasional uninvited snail trying to infest my planters, squirrels using the fence as a pathway, and the much-cursed possums and raccoons at night. And birds, of course, though I try to discourage them lest the household feline decide to sharpen her hunting skills.

Yes, it’s an elevated porch, but not exactly the barren swept-concrete patio some urban dwellers consider themselves lucky to have!

And judging by the compost time-trial that seems never to have been posted here, that difference matters.

For anyone who’s interested, here’s the recap:

Some time back, I tried my standard trenchless compost method in various containers, and determined that holes on the bottom are more important than any other container variable. Loosely covered is better than either sealed-top or completely uncovered, at least in my area, but any will work assuming there are holes in the bottom. Low and wide is better than tall and narrow. Metal, wood, hard plastic, ceramic, and heavy paper or cardboard all work (light paper breaks down too quickly, and then you get pests; heavy paper with no holes works to some degree, sometimes, but the conversion happens much faster once the bottom tears). Crockery at the bottom or lack of same doesn’t seem to matter much. But a container with no holes at the bottom will attract flies and/or other pests via any top-opening, will grow stinky if enclosed, and will convert to compost very slowly if at all.

Holes in the bottom will allow some gravity-pulled liquid to escape, which is good, but I decided the major advantage might well be to allow something from the ground to enter. Say, macro-digesters without wings?

When I thought to check, I found a few sow-bugs in an unfinished bucket (along with a suspiciously fat gecko -G-), and decided that might well be part of it. Soil-borne bacteria are another possibility--though that sounds odd considering the balcony is off the ground, it’s not too far off, and with a tree growing through the middle of it, dried leaves are common enough. And dried leaves that have been rained on have fairly high concentrations of rhodobacters etc. Not to mention whatever unseen contributions the wildlife may leave.

So I did another test: two trenchless buckets, one in contact with soil, the other on a bit of concrete walkway. (Got to love a landlord who lets you do such things! But it was the very end of the walkway, a part no one really uses but me.) The one on the ground converted faster than I’d expected--I should have done a three-bucket test, with the third on the balcony, but only had enough cured bokashi for two, sorry. The one on concrete...

Well, it there was no odor, thanks to the heavy soil-layer on top and bottom, but the raccoons found it eventually just the same. Cleaning up after them, I didn’t find as much uncomposted matter as I’d feared, though there were some sticky clumps I didn’t care to examine too closely. What I did find were flies in various stages. Earwigs. One scuttling beetle. And, when I moved the bucket, three earthworms that had bravely made their way across the concrete.

I assume that, had I left the container there, Nature’s clean-up crew would have taken care of it for me. But, earthworms notwithstanding, I decided it was time to declare that test at an end. Time to compost in contact with soil, in cool temperatures: five weeks. On the balcony with its varied lifeforms: about seven in that same temperature range. And on concrete? It was the end of week nine when the coons decided to help out. (I wonder what kept them! Thinking about it, they arrived after a relatively heavy rain...)

The obvious follow-up test probably would be trenchless compost buckets on upper-story outdoor spaces, some sterile and others as bosky as my balcony. But that will have to wait until I find someone willing to have a bucket full of dirt and ferment on their porch or balcony for an unspecified period of time.

In the meantime, I think I shall go build a leaf-pile on the balcony before the forecast precipitation. Maybe I can lure some earthworms up there!


(image from Small Planet Photography, for no reason except that I like it)


JMC said...

Hi there! I got so behind on my own blog I didn't realize you had found my link to your page and left a comment :)


I liked your experiment involving the different surfaces. My own planter does have holes on the bottom and is on dirt. I'm only on my second batch, and both batches have taken much longer than 4 weeks. I've also noticed lots of small, white larvae this time, whereas there were none last time. Is this normal?

D. S. Foxx said...

Normal? Yep. A good thing? Depends on your point of view. Insect larvae will speed the decomposition of whatever's in your planter, but they convert some of those nutrients into bugs, rather than compost.

I consider fly larvae a sign my planter's gone too damp; a heavy barely-damp soil layer on the top of my buckets keeps fruitflies and other such away, while seating planters on earth or leaf piles encourages sow bugs and earthworms. But a wetter planter attracts BSFL almost as well as an open bait-container without as much risk of off-odors, so I've been known to wet one down on purpose now and then.

If you're planning to use your compost indoors, flies are probably not something you want to encourage. (They lay eggs, you see...) Try increasing the soil layer, and be sure it is dirt you're using, rather than a soil-less potting mix.