I have a cucumber plant growing in a screened in patio. I have been trying to hand-pollinate the female flowers using both the paintbrush method and by stripping the male flower and rubbing the center on the center of the female flower method. After that, the female flower withers...but then my cucumbers don't get any bigger! My biggest one is 7cm and has been staying at that measurement for at least a week. The first few cucumbers were very small (like 2-3cm) and stayed like that for weeks. Eventually some turned yellow and I snipped them off. What am I doing wrong??