Get an automated light [window] opener, it works for free. A fan will remove plant food, [ good old carbon dioxide ] and force entry of a plethora of disease spores and spider-mites, apart from the cost of running a fan. A timed/sensed watering distibutor/mats will be better way to improve your glasshouse. I use bagged compost, not soil, and use it to pot flowers up the next year, third year as a soil improver. My little 8x6 produced 13 cantaloupe melons this year, plus 2 cucumbers a week and more tomatoes than we could eat. Best of luck next year and good eating!
Edited by Alan Belson (09/15/12 02:04 PM)
Wood work but can't!