Well, if you really don't have ANY time and are expecting zero maintenance, then I would suggest that the best approach is to make peace with the situation and accept the fact that some weeds are inevitable (shrug). ==>>> thats when you put 90% of your beds into wildflower meadow .. which is half weed anyway .. lol ... and then just keep a small formal garden for what time you have to do the job properly ... i have one space.. probably about 1/3 to 1/2 acre.. that i simply dont mow ... and you would be amazed at the beauty and diversity of what comes up naturally ... including all the wind borne weeds from the area farms ... and what grasses actually do.. when not shore every 72 hours .... that is also the beauty of dripping roundup around.. after dinner.. grab the bottle of scotch.. and the application.. and go spread some joy to your weeds ... its always a job.. if you have to make it a 10 hour.. all day Saturday job... but if you are just rambling around the yard.. after dinner.. as the heat cools and the sun sets.. you can kill lots of things in no time at all ... [just make sure you make it close to your own bed .. before you drain the scotch bottle.. lol .... its not good when the neighbors find you laying in the yard.. screaming obscenities at your weeds... face down in the garden bed ... threatening them with what look like a bottle of mustard ... and an empty bottle of intestinal fortitude ....] and a week later.. when they have started to shrivel ... they are real easy to pull out ... and discard.. if you dont want to let them simply compost in the garden .... man it hurts to laugh with a sinus cold ... ken

all excellent comments, I have a 1873 house close to a road intersection,, the house has casement windows. A alternative to Poly Carbonate is DR acrylic, damage resistant, acrylic Polycarbonate mix. A tough plastic, especially in 6mm (1/4inch) sheeting, it goes milky in excessive heat but good in shady conditions. To cut plastic simply use a tungsten tip saw, sharp with a clamped guide rail for the saw, (always have max revs before approaching the material, do not twist the saw slow forward and follow through,,,easy!, (or clamp between two pieces of wood, cut all three) a sharp carbon blade electric plane finely set to finish to size, if wooden frames glue and screw to rebated frame. If your window size is small, a glazier can supply toughened glass or laminated bullet proof glass at a reasonable price, but a UV PC pane (scratched pane) can easily be replaced. Remember ('a bit of Ossy', in this ever increasing 'shit world' God helps those who help themselves, love can be contagious!) the aim is to slow down would be intruders. If the windows are key locked internally a circular saw could only make the window look like Swiss cheese, from memory PC burns with high heat with black smoke, a don't think it would be a burglars option. have a nice day,,,Glenn Old Junction Hotel Neergabby Western Australia.

Very cool reuse! I imagine having the insulated walls will really help for extending the season/winter growing under coldframe! I maybe would be slightly concerned about drainage. Its tough to get an idea of how much "not sealing around the edges" will get you. A possible idea if you end up having trouble would be to drill holes at or near the bottom of the side walls to let excess water 'weep' out. I probably wouldn't do that until you've seen issues though.

A great alternative would be Polycoolite by Polygal. It only shows a 50% light transmission, but that is an overall light transmission. I have included a section of the chart for Polycoolite light transmission between 450nm and 700nm. This is where photosynthesis takes place. You can see that Polycoolite has between 60% and 70% light transmission in this range. I have used it on my personal greenhouse in Louisiana and loved it. That is my greenhouse in South Louisiana in the snow. That was quite the odd day. Polycoolite has diffused light properties as well. The ice sheets will not give you enough light. If you are choosing between ice and clear the choice should be clear.