With the snow still raging outside, the cost of Canadian food is rising inexplicably and ridiculously compared to the rest of the world. It’s time to take salad matters into my own hands. Herbs too for that matter. Maybe even some micro-greens like radish, mizuna, or amaranth. But I’m getting ahead of myself.
I’ve been reading about hydroponics
Romaine lettuce per “loose” head $2.49 – 4.99
Romaine lettuce hearts per 3-pack $3.87 – 5.99
Bibb (aka Boston) lettuce per head – $3.89 – 5.89
Herbs (e.g. basil, rosemary, coriander leaf, thyme, mint, sage, etc.) per 4-8 stems – $2.29 – 4.99
Spinach per 225 g bag – $2.99 – 4.79
Watercress, arugula, mizuna, etc. – unavailable for purchase in winter
And don’t even get me started on tomatoes from Mexico that are little more than expensive and tasteless red baseballs. But they’re for a later experiment. I just want to tackle the leafy greens at this point and hydroponics on this scale can be surprisingly easy for those crops it seems. Or at least I hope.
There are several ‘home hydroponic’ kits on the market but these all seem to fail to me on several counts. First they’re not cheap. I don’t want to spend $100 on a kit when I know full well that the plants don’t care what fancy gizmo they grow in if given the food, water, light, and warmth they need. You’d have to grow a lot of lettuce to recoup that initial investment and I know they’re not much more than a pretty bucket with an air pump and some fertilizer tossed in.
Secondly they all seem to produce too few plants. At least until you cross over into the $300+ offerings. If you can’t produce an abundance you’ll either out consume the system or the few plants you do grow will become too precious to you and you won’t eat them with wild abandon as you should. I want to have enough greens that I don’t really know what to do with them all beyond eating yet another salad and sharing with my neighbours.
Finally, some of these “indoor grow your own” gadgets rely on ridiculous proprietary seed pods or fertilizer packets and have unreasonably priced replacement bulbs. Basically they made to keep clueless gardeners in the dark about the process. Convenience kits are little more than a novelty on all these points so it’s a DIY solution for me.
This is also going to give me a chance to really understand the inner workings, simple as they may be, so that I could potentially scale up once I have the greenhouse space established on the farm. A corner dedicated to hydroponics for myself as well as a few gate sales of herb bundles wouldn’t be a bad thing at all. And of course all this “technology meets plants” stuff is all right up my geek alley.
There are several major threads in hydroponics these days including “Ebb & Flow”, “Floating Raft”, “Nutrient Film Technique”, or “Drip Channel”, but the most interesting to me at the moment is “Deep Water Culture”. Simply put it’s a static reservoir of precisely calibrated liquid nutrient with the plant suspended above at a particular height to encourage roots to grow down to reach the food. The solution is mechanically “bubbled” to add oxygen and the reservoir is shielded from light above being generously applied to the leaves of the plants. To be clear, this is pure hydroponics growing in a soil-less nutrient solution. Considerably different are airponics (using a misting or air-carrier to feed plants) or aquaculture (systems incorporating aquatic organisms like fish or shrimp to form a bio-cycle). And while my chosen version is one of the simplest, there are still a few stumbling blocks along the way to make it work on a small scale indoors. Most notably light, temperature, and nutrients, all of which are usually controlled by supercomputers with OCD when done on a commercial scale. My little desktop experiment will just have to try to muddle through.
Giant operations start from seed in fairly dense plantings on ‘grow cube’ grids. Once sprouted they soon get transplanted up the chain into wider and wider spacing, all while swimming in particular brews of feed solution.* Since I’m small time, I’m going to try and start my seed in the very same spot it will stay its entire life. No extra starter pods to buy and no transplanting of any sort. This might seem counter intuitive for an indoor space where real estate is at a premium but really it’s not. You have to consider that commercial operations are looking to maximize production and in effect need a constant stream of plants ready to harvest at will. My goals as a personal consumer are different. I likely want less than half a dozen plants maturing at any given time with six of their cousins ready to eat a week later to form a constant cycle.
* The popular “How It’s Made” series has featured a few hydroponic operations and should give you an idea of how the big guys do it for comparison. Search the googly-webs for examples.
So my experiment is going to aim for two dozen plants spread across three or four bins. Because my room temperature is fairly cold, about 15C with dips on colder nights, I’m going to gently heat my growing solution to the plant-friendly mark of 20C. Since my total volume is less than twenty gallons, a small adjustable* aquarium heater will do the job nicely and without much power consumption not to mention handy thermostatic controls I don’t need to tend over time. I plan to geek hack a little temperature sensor for my existing one-wire network that already monitors indoor and outdoor air temperatures so that I can record water measurements over time and set up alarms should things accidentally get too hot or cold. I may even mount some grow-cams so you people can watch the progress as well.
* Many heaters of this type are preset to a constant 25.5C (78F) which is great for fish but unacceptably high for hydroponics because oxygen uptake from feeding solutions diminishes at that temperature. Adjustable versions can be had very inexpensively (< $5) online from China.
One interesting trend in deep water hydroponics comes from a researcher in Hawaii named B.A. Kratky or as the online hydroponics enthusiasts call it, “The Kratky Method”. Several papers he produced showed that leafy greens could be grown ‘hands off’ in a system without any power given the correct ambient temperatures. Most importantly, he showed that aeration of the growing solution normally employed in hydroponics wasn’t necessary for leaf crops and that air pruning of the roots that naturally occurred as the solution was taken up by the plants (and the water level decreased) had a beneficial effect on the crops. While these are very interesting findings, the scale of my experiment means I can add aeration for the minimal cost of an aquarium air pump and filter stone and all reports seem to say aeration helps when added. Plus if I ever want to attempt fruiting plants (e.g. tomatoes, cucumbers, etc.), I’ll be ready to try since they almost universally require the bubbles to keep the solution oxygenated. For the curious, this is accomplished in other types of systems using a variety of methods including ‘waterfall’ agitation and recirculating pumps. In tiny systems you can even use a hand whisk a few times daily.
Lighting is super easy and already in hand from my soil-growing days. I own several SunBlaster fluorescent grow lights I bought from the company headquarters back in British Columbia when they were just up the road from the mountain house. As you can see they work a treat for starting traditional seedlings. They also consume very little power (< 50 watts) and can be set on timers to automatically normalize and extend the light cycle plants prefer. Not something Mother Nature provides to us here in Canada during the darker months.
The really tricky question for my experiment comes when I get to the nutrients. Thanks to the explosion of home hydroponics as well as a fairly mature pot growing community*, there are hydroponic supply stores everywhere here willing to sell me perfectly balanced liquid nutrients for exactly what I want to grow. But therein lies another sneaky cost. Those ready-mixed solutions are none too cheap with a typical minimum two litres of concentrate costing on average sixty bucks. I want to try to tackle that chemistry myself and formulate something less expensive, perhaps even organic or using some local resources left over from the seafood industry. Stay tuned for more on that part of the big equation.
* Illegal or not, clever pot growers in Canada have been sorting out these systems for decades behind closed doors and have most of the questions about light and nutrients in a contained system well answered. Lettuce and mint aren’t that different from weed. Much easier in fact it seems since you don’t eat lettuce ‘buds’. I know I’m reinventing a lot of wheels they’ve already spun but it’s the best way for me to learn the details. Plus they’re loads of fun to talk to in the forums, especially when they’re stoned and trying to remember nitrogen ratios. “Uh, dude… That’s 28% uhm… are those brownies?”
That touches on cost but if I can cobble together this system from parts I already own and recycled containers, I can get my expense for a big bunch of herbs or a head of lettuce under a quarter. I know the dollar amounts I’m talking about aren’t huge and many people would rather just spend a few bucks on salad greens but if I can make it work cheaply, nearly hands free, and without much power consumption, why not try? I’d also know my self-produced plants had no nasty chemicals or long trips from foreign lands. I’m not generally a food safety or security alarmist but you can’t help but notice the growing number of recalls for things like e-coli contamination that come from the giant mono-culture the greens growing industry has become.
Not to mention I can plant whatever whacky varieties I can find seed for and you can’t get that sort of variety at any price in the stores. Stay tuned for updates as things progress.
