If you have a Greenhouse why not fix a 1/2in hose pipe with small funnels from the gutters to collect rainwater and run them to the bin to save water. It`s a job for a DIY person but well worth the effort and your plants will thank-you for it. I put a small piece of mesh in the funnels to stop any muck going down the hoses, and I block off one end of each gutter to stop rainwater running off one end.