I used the "buried milk jug" method for years. Worked great for me. I used
concrete reinforcing wire for my tomato cages so I had a cage several feet
across and 4 feet high. I planted 3 tomatoes in each cage with a jug in the
middle. I used one of those very long spouted plastic funnels you can find
in an auto parts/supply store when I wanted to put fertilizer water in the
jug from a watering can, otherwise I just took the sprinkler end off my
water wand and stuck the pipe into the jug. I also used the buried jugs for
my squash and melon plants.

I heated an ice pick on the burner of the stove till it was red hot and then
made 2-4 holes on the bottom edge of the jug, depending on how much watering
the jug was required to take care of.

Val