Gravity drip irrigation

I’ve been setting up a system of cheap drip irrigation for a remote location. Here are the facts and criteria

1. Remote, no electricity, off-grid
2. Water from well, well pump run only by generator
3. Multiple trees
4. Drip time before refilling (about one per week)
5. Hot summer (80-100F), wet mild winter
6. Windy site, full sun, no shade

Here is the setup so far:

1. 1/4 tubing
2. 1/4 tubing w/ 1/2GPH emitters at 6″/12″ spacing
3. 1/4 fittings (tee, connector)
4. 1/2 tubing
5. 1/2 fittings (tee, connector, cap)
6. mini sprinklers
7. 1/2 GPH PC/non-PC emitters
8. Trash cans (32G), many, cheap at OSH $10/each, this acts as the rain barrel, container
9. 8x8x16 Concrete blocks ($1.48=>$1.54 at HomeDepot)

Basic steps for a single emitter

1. Drill trash can to connect out to 1/4 pipe with valve
2. Connect 1/4 tubing with 1/2GPH emitter at the end
3. Place water container on top of concrete blocks to create pressure
4. Place emitter at base of tree

Other setups:

1. Single tree, single barrel
2. Single barrel, several emitters

Problems encounters:

1. Run out of water from a single trash can too quickly
2. Time to manually water and refill containers