I suggest that if you are at times away from the greenhouse for extended periods. Then a system that is supplied by the mains water. Make sure any taps are fitted with a non-return valve, this prevents contaminated water getting back to the main supply. My layout is this. Connected to the outside tap, I have a heavt duty 1/2" hose permanantly to the Green house. In the GH I have a tap plus a two-way, or double take-off. One take-off supplies the garden hose, the second supplies my GH irrigation system. I have connected to the GH out-let a battery operated timer unit, cost £12-£15. Then I used a cheap green plasic 1/2" hose. This is attached to the outlet of the timer unit. This hose is now attached to the inside of the roof glazing bars via pipe clamps. The hose runs the length of the GH, crosses a few feet short of the end, and runs back down the other side. The end is sealed by means of bending the hose upon itself and securing with a jubilee clip. I bought a pack ot two of small jet valves cost, max £5. Then using a bradawl or a one inch wire nail, I Punctured the hoes at intervals of about 18" The jet valves easily screw into the plastic hose. Now test time. Turn the water on, starting with basically the tap just open, the gradually open a bit more, until you have just above a med mist spray. Now set the timer unit according to the manufactures instructions. Over past years. I have been away from home for three to four months at a time. Back home, and the GH has been better cared for in my absence. Hope this helps. PM me if needed. Mike.