Tuesday, May 7, 2013

Third World Green Daddy 50: My garden

Ever since my wife and I began our mammoth house rehab project a few years back, I've been planning on and yearning to start a rooftop garden.  It eventually became part of the design of our house, and probably accounts for a fair share of the headaches, cost, and time we've suffered during the project.  But now it's done, and on January 29th of this year I finally planted my first crop.  This blog is to explain how the garden works, and to show off the fruits of my labor.

Since last year I'd made two long planting beds whose final soil height would be at about 1 meter high, perfect for gardening without bending over.  The ultimate goal is for the plants in the first planter to receive their irrigation water from our greywater supply (that is, all the used water that comes out of our showers and sinks, but not the toilet), filter the soap and food particles from this water so it drains into a water tank where I'll raise fish for our household consumption, then have the water pumped to the second planter, which will filter the water a second time so we can use it to flush our toilets.  Getting all this set up took a long time, between designing a soil medium that will provide the plants with nutrients yet leave water clear after passing through it, getting the pumps working, etc.  But finally by about mid-January 2013, I'd put the finishing touches on the filter system (which ended up not working anyway!).  It consisted in a mix of sand and charcoal, overlain by a thick layer of rice husks.

These rice husks were kept from floating to the surface of pumped water by sisal sacks weighted down by rocks, and then a bit of soil from my father-in-law's farm to provide some biological activity in the mix.

On top of this went uncomposted horse manure, composted manure from my heifers, a bit of worm compost from our house, and finally rice husks to keep down weeds, smells, and surface evaporation.

When I finally had a good seedbed ready, I carefully chose what I wanted to plant.  My main criteria were to grow things that either aren't available in our small town (certain succulent varieties of tomato, for example, or lettuce beyond our town's Iceberg/crinkly leaf divide), or that I know are normally sprayed with lots of toxic pesticides.  I have two tupperware containers full of dozens of seed varieties that I brought over from the US in 2008 when we first moved to Colombia.  Our plan back then was to start a market garden outside of Bogota or on my father-in-law's farm.  That plan never panned out, so I was left with a bunch of seeds that I longed to use before they became old and inviable.  I'd done some unfruitful gardening experiments in a house we used to rent in the Tenza valley when my wife worked there, and we'd actually had some success growing cut flowers like zinnias and sunflowers at my father-in-law's farm.  But for the most part those seeds just sat in their boxes, waiting for me to set up a functioning garden.

There were far too many varieties of seeds for me to plant them all on the rooftop, so I chose just a few things to start with:  a gourmet cut-lettuce mix, a bibb lettuce variety, green beans, 3 heirloom tomatoes, mini carrots, sweet-hot wax peppers, two types of melons, basil, mustard greens, and long, skinny beets.  I also transplanted two volunteer tomatoes, an uchuva plant (it's an Andean fruit, that thing that looks like a yellow miniature tomatillo but is sweet), and a Brussels sprouts plant I'd had languishing in a pot in my patio for months.

I like to pre-soak my seeds before planting them.  Actually I don't--after a night of soaking the seeds are always too sticky to reliably plant one-by-one in their holes.  But since pre-soaking sounds like a good way to speed up germination, I always do it if I haven't gardened in a while, and then I regret it.

So I lined my different varieties up, with a plate for each group of two seed varieties (this way I economized on plates, since you can easily distinguish between tomato seeds and beans, or beets and lettuce, etc.).

I left these with a shallow pool of water overnight, and in the meanwhile I charged our live-in adolescent Carlos with stretching twine from the greenhouse ceiling to buried sticks in the manure mix.

I had earlier laid out an old garden hose from the pipe that came from the greywater pump, and I had spent an afternoon cutting slits in it just so to get a more or less uniform coverage of the whole planter, then taping up the most gaping holes where all the water would come out before reaching the end-most slits.  I emerged from this smelling as you might imagine someone smells after being doused with stagnant, fetid washwater.

I planted all the seeds January 29th.  I planted many more than I needed, three for every hole where I wanted just one plant, in part because I wasn't sure how their germination rate would be after 4 years in storage, and in part because with those damn presoaking plates I couldn't just pick up seeds one by one.  All my plants came up quickly, except for a Waltham 29 Broccoli seed packet of my father's from 1983 that I planted all of in the hopes that at least one plant might come up and serve as a link to my dead father and to my own infancy.  No such luck.

By a month after planting, the crops were starting to really grow.  I got a 5-person salad's worth of baby lettuce after like 4 weeks.


Carlos helped me harvest.

And we stuck the leaves in cool water so they wouldn't wilt in the midday greenhouse sun.

Here was how the rest of the garden looked a month after seeding.

I have also been caring for a few tree seedlings that I intend to plant at my father-in-law's farm as shade for my eventual coffee plantation.  I'm raising avocadoes of different varieties, some live oaks from Spain, and a leguminous plant called Huayruro from Peru.  None are native, so if they do actually thrive in the conditions of the coffee plantation, I'll have to keep an eye on them to make sure they don't harm the native ecosystem.

Three weeks after the first cutting of baby lettuce, it looked like this:

I filled four large Ziploc freezer bags with the lettuce harvest, and gave it away to friends, since my family still wasn't living with me and I couldn't eat it all myself.  Here was the rest of the garden at that point:

Three weeks thereafter (early April), I was harvesting a lot of my long Forono-variety beets.  We sautée beet slices in butter, water, and salt, and the leaves we use in soups or alone as cooked greens.

Two weeks ago we harvested all the basil, plus a few pounds of green beans, lettuce, and collards.

The basil served for our first batch of pesto in years.  If we were still in the jam and pesto business, it would have filled maybe twenty small (125ml) jars that we sell for $2.50 apiece. 

For more than a month now we've had constant harvests of greens, lettuce, beets, some carrots, basil, and Brussels sprouts.  We harvest these in such a way that they re-sprout, so they act as perennial plants  The tomatoes are filling out, but none are ripe yet for the picking.  I don't know if we'll get any melons.  They keep flowering and making little melons, but these then wither on the vine.  We are far from totally replacing our fresh produce purchases, but our market trips have now mainly shifted to provisioning us with fruits and staples like plantain or potatoes. 

My original plan was to triple-recycle our greywater.  Once as irrigation water, again for raising fish, and a third time for flushing toilets.  As yet we're only doing the first step, but I hope to get my aquaculture setup organized soon.  This greywater recycling system is parallel to but separate from our rainwater capture, which was inactive during the long dry season.  But now that we're back in the rainy season, almost all of our household water use (showers, toilets, wash machine) comes from rainwater captured in belowground tanks in our patio, pumped to the 5000 liter tank on the third floor, and then pressurized with another pump system to serve the whole house.  The only time we use city water is for our kitchen cold water (which gives us our drinking water after boiling), and whenever the rainwater supply runs out.

In short, we are not totally off the grid in terms of water and food, and we never will be under our present system.  But we are able to replace part of our outside consumption, enjoy higher-quality, pesticide-free vegetables that we wouldn't be able to find elsewhere, and comfortably weather the occasional cut in city water supply.  On top of that, our rainwater capture system helps the rest of the city by buffering the massive flush of water that would otherwise enter the city sewer from our roof gutters.  A few times every year in our town the sewer spew out rainwater during heavy storms--we've even seen iron manhole covers pushed off by a geyser of poopy water.  If more houses in our city had a rainwater capture system like ours, this wouldn't happen.

I'm happy to offer advice to anyone looking to replicate our rooftop gardening setup.  Shoot me a line in the comments section, and I'll respond to you.


  1. This is very interesting blog. I'm very fond of gardening and sowing fruits and vegetables. It's been very nice to read your article.

    Finn Felton
    Kopi Luwak

  2. Very interesting project, congratulation!!!