Don't overwater or let the greenhouse get too damp (I know it's difficult with other plants in it) or you will get mildew - or rather the cucumber will). Feed every couple of weeks - I use tomato feed and put some canes up from the cucumbers and across the top of the greenhouse so they can attach their tendrils to it. You may have to tie the stalks first until the tendrils catch hold. Happy cucumbering and I guarantee you will be giving them away to anyone who visits as you should get masses of them. ps you don't have to wait until they are huge before you harvest them.