Well topcat, you are in the Container Gardening forum so, hope you are reading the postings. Raised beds sounds like a lot of work to me, can't shift them around easily if you make logistical mistakes , concrete cuts you off from ground & you don't own the site indefinitely. Grow what you like to eat. In 300 sq. ft. enclosure choose dwarf varieties & aim for good air circulation among a succession of vegetables. Make a seedling "nursery" someplace else to optimize your use of the greenhouse space. Control that electric bill by choosing seasonal crops that match up with outdoor temperatures. You didn't say if can ventilate by opening windows. Your room height was not mentioned. If the overhead water is drip emitters & not fixed sprayers you have versatility.

I would call the Conservation Fund this is a big part of what they do. There will definitely be someone there that can give you an idea on this. Good luck. Link below

Maybe these links will help: Your Conservation Easement Easement Brochure Land Conservancy NJ Green Acres Program

heptacodium has a point. There are clients who just want cheap, and they get what they pay for. The really nice looking plants are serviced by companies who charge more and deliver more. It's kind of like a McDonald's meal vs. a fancy steak house. You pays your money and you takes your choice. Right now, with the recession looming, people are getting very price conscious, and hiring the lowballers or cancelling the plant service altogether. It's a tough time to be getting into the industry, or trying to stay alive in it. There is also a real swing away from the "fern bar" look of the 70's and 80's to a stark minimalist look. Just one or a few big striking plants in a fancy, artistic container. Lots less maintenance income to be had on that.