Here's a tip that will keep your plants in better condition by giving them water slowly in a sustained manner over a few hours - or even days.
What you need is a two litre PET bottle, and something to make a hole with. If you don't know what a PET bottle is, the big 2L PET bottles are the largest size ones that soft drinks like Coca Cola come in at the shops. This kind of bottle works better than cordial or milk bottles, because PET bottles do not degrade if they are left in the sunshine. You'll want to wash the bottle first or the sticky soft drink residue will attract ants.
Punch a small hole in the bottom of the bottle by using a nail, by drilling a hole with a fine bit or by using anything else sharp (personally I use an old school compass). When the bottle is filled and has the lid on tight, no water should come out of the hole. Loosening the lid a little will adjust the flow rate out of the hole, and you can set it to a bare drip that will last for days, or to a fountain that will empty the bottle in a few minutes.
PET bottles are made out of stiff plastic, so if you use recycled grey water (eg, from keeping old bath water) the hole in the bottom of the bottle should stay open and won't clog up with sediment.