We've been chipping away at this whole renewable ammonia thing for a while now – the worry being that the 50% of human consumed protein that has its roots in the natural gas/coal driven ammonia production is in danger, first from natural gas depletion, and second from concerns over carbon dioxide emissions from the extremely dirty coal gasification process.
One of the things that comes from an ammonia plant is a flood of low quality heat – 160F water pours through the electrolyzers as the plant makes the hydrogen needed for the ammonia synthesis. Greenhouses are the first and best use we've found so far for this heat, so I've been learning a bit about them.
And it turns out that you can make them all organic if you're willing to play a few tricks on Mother Nature.
The enemies of plants are three: other plants, insects, and molds/fungi.
There is simply no need for herbicide in a hydroponic operation – the plants either float in a tank full of nutrient solution, supported by a bit of rock wool or other such material in a little plastic cup, or they may be placed in a nutrient film system with a circulating solution.
Insects are a big problem outdoors but in greenhouses there are simple cures for small, uninvited guests. The first is positive pressure. Well screened fan intakes keep bugs from entering there and a good stiff breeze blowing out any opening makes entry difficult. The second is a harmless,natural insecticide – carbon dioxide. Atmospheric carbon dioxide is about 380 parts per million (ppm). Get your greenhouse workers out of the facility, jack the CO2 level up to 10,000 ppm, let the air circulate a bit while the concentration falls back to the 1,500 ppm safe for humans and optimal for plant growth, and there won't be a bug alive inside the place.
The third source of trouble is the things that blow in no matter how tight the facility is and contaminate the nutrient solution. Fungal growth, spread by airborne spores, is a common problem but there is a fairly simply solution. Ultraviolet light at intense levels easily destroys fungus, but care must be taken to avoid damaging the nutrient solution in the process.
Besides the chemical free nature of these facilities they're also going to produce in high volume. Vegetable crops need between forty and sixty watts per square meter which would be pretty expensive in most parts of the country, but renewable ammonia plants have to be close to cheap electricity, so plants will have all the light they need.
Right now if you buy a hothouse tomato you're getting some hybrid selected not for being a tasty treat, but instead for being as close to high density polyurethane foam as possible. Large volume growers want something that will be regular in size, solid enough to survive shipping, and then adding insult to injury they're picked green, shipped, and then ripened. They only look like tomatoes ... until you bite into one.
Why would you use a variety like the ones I describe above if the greenhouse is just the right size for the local market? The answer is simple – you wouldn't do such a thing. Instead of a monocrop of boring tomatoes the operator would go to a place with heirloom seed lines, like Seed Savers Exchange, and pick up a bunch of different varieties. Since the market is local there is no need for the storability associated with the 'plastic' varieties and the extra care required to handle the picking and packing of odd sizes would be worth the premium that an organic heirloom tomato would command.
I don’t' know all that much about this stuff yet. We just issued an RFP for a one hectare greenhouse module that'll become standard for any ammonia plant we design where greenhouse operations are needed as a heat sink. I'm hearing a lot about the different hydroponic systems – some are heavily advertised but don't work all that well. It seems the real greenhouse gurus are from Holland and Israel is close behind in terms of recognized skill.
I penned this as a sort of quick description of greenhouses that I can use elsewhere – Dkos just happens to be a convenient repository. I must admit I'm getting a little confused on what is where – I am current writing here, I'm doing professional grade articles for The Cutting Edge News, I'm covering a bit for Ilargi over at The Automatic Earth, and I don't see it yet but I submitted my first article to OpEdNews after the editor, Rob Kall, interviewed me the other night.
Oh, and lest anyone stumble upon this with the Google and out me I'll just admit it – I'm having some interesting discussions over at this new Republican site - Rebuild The Party.