Posted: 11/04/2014 at 10:55
Not much choice then Marion, I have a watering system bought twenty years ago when friends let me down (forgot they had promised to water) still works well but fiddly to set up.
Collect anything that will hold water old washing up bowls buckets plastic trays even cardboard boxes with cling film or plastic inside. Buy a bag of fine gravel cover the bottom of the boxes etc. then just cover with water.
Set all your pots into the boxes trays etc. packed in close then give a good watering before you leave, put a bit of shade up in case of a hot day, (you do get them in Scotland now and then) but do not cut off all light.
I also collect used lemonade bottles or plastic milk bottles, punch or drill a couple of holes in the cap fill with water then water the larger pots well and up end the bottle into the compost, as the compost dries the air gets into the bottle releasing the water slowly, it works for me in outside pots and hanging baskets.
You may find it policy to leave the vents and door open to keep your greenhouse-- garden hut cool, less loss of water.
Hope some of this helps.