This is a garden waterer made from commonly available parts. Technically, it is completely modular, so using couplers and other stuff you could link several together to water a whole garden at once. This is just a one-row version.

Step 1: Materials

You will need:

3 Pieces of 1/2" Schedule 40 PVC. Make it several inches taller than your tallest plant that you will be watering. Also, be sure to allow ample room to stick the pipes into the ground.

1 10-foot long piece of 3/4" Schedule 40 PVC. I chose 10 feet because that's about how long my garden is.

1 3/4" end cap for the PVC.

1 3/4" smooth to 3/4" female threaded adapter.

3 Metal Pipe Straps.

6 Screws to hold in pipe straps (must be same size as pipe strap holes)

3 1/2" diameter tee connectors.

Tools:
Drill
Dremel (optional)

Step 2: Make the Support Towers

Take the three 1/2 " PVC tees and place the pipe straps on top. Mark where the pipe strap holes are, then drill them out with whatever size drill bit fits the screws you're using. Fix the pipe straps onto the tops of the tees by screwing in the screws. Stick the tees on the three pieces of 1/2" PVC. You've just finished the supports.

Step 3: Prepare the PVC

Drill a whole bunch of holes in the PVC as shown in the picture. These will provide the water shower for the plants. I used a drill bit the size of my Dremel collet, so anything similar to that should work. Use a Dremel if you have one, since they're lighter than a drill and make drilling the pipe much easier and faster. Be sure not to make the holes too big, and be sure to only drill them on one side, not all the way through. Stick the end cap on one end.

Step 4: Put It in Your Garden

Stick one of the supports in on one side. Stick the open end of the 10-foot pipe into the pipe strap. Next, place another support in the middle of the garden. Stick the pipe through that. Then, do the last support on the other end of the garden and stick the pipe through that. Attach the threaded end of the adapter to the hose as shown in the picture, then stick that onto the open end of the 10-foot pipe.