The simplest way to irrigate your garden is to use a hose. Just come out here every day, and just spray down your plants. But, if you don't have a lot of time to dedicate to your garden, this might not be the most practical option. Another option is a sprinkler system. You can set it so that it goes off at the same time every day. But, a bad thing about a sprinkler system is that if it rains, and the sprinklers go off, you can over water your plants. Or, if it's dry, you might not water it enough. Another option is ditching. This gives you a central line where you can modify your water level. Now, this may be old fashioned, but sometimes old fashioned works the best.