Could multi-level greenhouses help provide more food / resources?

Question

As I watch farmland, in my area, converted into townhouses, stripmalls, and McMansions I have day dreamed about an idea.

Why not build multi-level greenhouses - several stories high, primarily high-strength construction glass where plants are grown in a hydroponic environment. Maybe add solar panels to power water/nutrient pumps and additional lighting when/where needed. One acre of land could potentially grow several acres of food.

Anyone have any thoughts on the feasibility of such a project or any resources I could be directed to?

Answer 1

Actually, I'd like to put in my two cents that a pyramid style stepped greenhouse could quite possibly be a great way to increase productivity.  If you combine the stepped pyramid with a system of mirrors for increasing lighting...  and plant very carefully.  

Of course, you'll have to plant high light items on the North/South steppes.  Mid light items on the East/West steppes.  And use the center of the structure for low light items, setting seedlings, and work area.  If you use high strength glass block flooring you'll increase the overall light in the building (I saw this used in a sky scraper, and it was a Really great setup.  Pretty too).

Not a bad idea really.

Answer 2

You can imagine agricultural activities which would benefit each other, like growing vegetables and keeping poultry in Europe. The poultry produces heat on which the vegetables can thrive. Often it becomes difficult when you have a plague of insects which have to be sprayed. All chicken will also die...

Answer 3

as for feasability, you nee to consider the lighting more. the plants will be in perpetual shade, which means lower yeild. supplementing with solar won't provide enough light as the best soloar panels are about 20% effiecient. so best case is 20% of the light hitting the roof could make it ot run lamps inside. you would do better to make the roof and floors transparent. you could run lamps off the electric grid, but that drives the production cost up.

as for resources, sadly the most info can be found in 'head shops' and high times magazine which promote marijuana growth.

Answer 4

When I went to college I studied agriculture and fell in love with hydroponics and greenhouse production. I have worked on a number of projects over the years, my pet project being hydroponics done 100% organically with a tandem aquaculture project. Suffice to say I spent a huge amount of time mulling over  issues of increasing production area ratios of a greenhouse; more usable space means a greater amount of production, but only to a point.

First of all, in one pilot project which was a lettuce house, the building was 32' by 110' and I had a whopping 90% production area and could grow a maximum of 220 heads of lettuce (boston bibb) daily. Problem was with so little work space (10%) it was difficult to actually work. The lettuce was on large floats and one little problem like a float hanging up or if you had to get to the center of the nutrient pond, it was a REAL headach. And aside from the basic packing, everthing else had to be done out side, like float cleaning, as there was no room inside around the seeding tables. So a high ratio of production space is a two edged sword.

Now look at your proposition, and yes, it is a good one when you work out the problems. Sounds to me from your question wording that you are in the United States, although where you are really has no bearing on the question except physical situation of a facility. I'm in the northern US and keeping that in mind, a southern facing facility picks up the sun here, and is the same anywhere in the northern hemisphere. If you build a tall greenhouse;

1) The space in the shadow to the north can not be used for a second greenhouse and the higher you go the more unused space you will have. Long winter shadows get longer the more you go northward in the country but even summer shadows can be long. So you can only have additional facilities to the east and west or your total production of all houses on the land will be diminished just because you have dead space between houses. You can have south side greenhouses added to a building that is not sun dependant like a fish farm (aquaculture production, fish don't like sun as plants do). This brings us to the next problem...

2) If you build a multi leveled greenhouse, the floor above would cast a shadow and decrease production below. Even a clear floor or one made of grates will be low light. So the actual width of the building would necessitate making it narrow. The only other option would be to use a leaning "A" frame with the south side angle perpendicular to the sun's winter extreme angle. What I am saying is the angle, which is dependant on your location must pick up the winter suns rays dead on or much of the needed warmth and light that the greenhouse grower depends on in the winter months is reflected of the glazing. This means more money spent on heat and slower growth due to lower light levels. A good greenhouse construction and management manual will tell you the best angle for your structure based on your location in the form of a graph or table. And even with this leaning "A" frame greenhouse with a straight north wall you can only go just so wide because one floor shades another, so you can only then go so high. The only other thing is roof tops of "other use" buildings. At an aquaculture facility that I spend time with, greenhouses where on the roofs of the buildings where all the rest of the labs, offices and production went on.

The reason that greenhouse facilities are as they are is the logistical nightmare and physical plant issues and construction problems. High greenhouses with production in the rafters works as long as the overhead production does not overshadow too much the lower production. The big greenhouse box also provides a big air mass with a lower actual surface area exposed to the outside and heating is less of an issue. The long, low hoop house with the inflated double wall is a great production facility but you must have the land to set it up. Rows of these can be set up fast and they are a breeze to work with and very cost effective. With a little high tech, even more so. For that reason, it is hard to beat the general design, be it double inflated poly or the translucent quonset house style.

Though your idea is great, I think you can see the issues. Even if you could set up a series of reflective white panels it is still a problem, and we don't have the technology yet to use solar panels to run lights to augment light loses. That is still to come. You can set up your work area below your greenhouse. The set up I had that was 90% growing was way too difficult to work with so more area was needed, and working outside in the snow because of limited space is not much fun and can damage equipment.