A good old bodge I have seen use, successfully, many times is this:
Take a length of garden hose that will reach from your outside tap to the object to be watered (allow a little for going around corners etc). This hose needs to be one you don't mind cutting up, you will see why in a min.
Get a bung for the end of the hose (a big bolt, wine bottle cork or anything that will fit)
Something to secure the bung (jubilee clip, tie wraps at a push).
Connect hose to tap.
Run hose to where you need it.
place bung in end of hose
Secure in place
Go to the point where the hose meets the plants and bury the hose. If there is no room to bury it (likely with tomatoes), secure it in some way so it doesn't get knocked about by roaming cats/wind etc.
Now take a sharp knife and punch small holes in the hosepipe near the plants.
Once you are satified you have made enough holes, go back to the tap and turn it a TINY bit, so it is just dripping.
Go on holiday.
Return to happy, watered plants.
