Wherein I propose to DO SCIENCE
I came across an interesting study recently while researching the relative environmental impact of hydroponics systems. Run by defra in the UK, it compares the impact of food grown in the UK with that of food imported from abroad in order to test the idea that locally grown food is always better for the environment. The results are mixed, of course.
What got my attention was that one of the foods examined was tomatoes, grown hydroponically in heated greenhouses in the UK, or in soil in Spain. The hydroponic tomatoes come out worse in terms of greenhouse gas emissions due to the heating (and they also pump CO2 into the greenhouses to aid photosynthesis), but better in terms of water usage, runoff and land usage, so it’s not exactly clear cut. It’s also not exactly the same situation as what I’ve got going on here. How does a home-grown hydroponic tomato compare to a Spanish tomato, or even a UK tomato? Well, they provide some decent figures for each case, so it may just be possible for me to figure it out!
What I’m proposing is to grow a tomato plant in my original system, record the energy inputs and the yield, and from that calculate the CO2 emissions per tonne (ha!). I’ll figure out the monetary cost as well while I’m at it. There are some caveats of course: I will not be including heating costs like the UK greenhouses in the study, because I would be heating my house anyway, I will be using CFL bulbs where more powerful ones are recommended for tomatoes, I may not be able to determine the environmental impact of manufacturing the nutrients I use (though I have contacted the manufacturer), I will not consider the impact of manufacturing the system itself… Also, I have never grown tomatoes before, and I hear they are difficult, so the initial yield may be low. Still, I think an attempt or two will at least be educational, and hopefully quite tasty. Am I wasting my time, money, and destroying the environment by not powering all the equipment with renewable energy? Only SCIENCE* can tell me!
