I set up capillary matting on the greenhouse bench, in a waterproof framework, with one end submerged in a trough of water. This appears to be consistent with descriptions I have read about how to use the matting. The top of the reservoir was just level with the top of the bench (ie the water level would have been lower than the bench) but even so the whole area of matting flooded. Any ideas what I’m doing wrong please?
It sound about right, I would suggest that you lower the reservoir a little at a time until it's about the right amount of water in the matting. Otherwise you might check the level of the bench with a spirit level and raise the opposite end slightly.