A rain barrel's an old-fashioned irrigation system, designed to make maximum use of nature's mositure and help a garden make it through times of drought. It's time-tested, and it works.
All that's required is something to catch water, somewhere close to the garden. A wooden barrel under a drain spout is traditional, but plastic trash cans will work. I recently saw a shore garden that had plastic wastebaskets scattered through it to catch rain and make it easy to give it back to the ground.
Except for extremely polluted areas, rain water is pure water, not fluoridated, chlorinated or softened.
Any farmer will tell you it's the best water there is for good crops.
If you put old manure in the bottom of your barrel, it will mix with the rainwater and brew into a nutritious tea that will satisfy both the thirst and the hunger of your garden plants.
Today we have hoses, running water and all kinds of sophisticated sprinkling systems, but in many places a rain barrel and a thick mulch will still work as well as anything else to carry a garden through all but the most severe droughts.
For several year there was no water outlet that could reach my garden without more hose than I could afford. I had been a waterer, but then I looked around at farmer's fields and saw that they still rely on rain to irrigate many of the crops. So I gave up on a watering schedule and put down a thick layer of mulch. I kept a rain barrel under the eaves of a nearby shed and also carried occasional buckets of water from the house - but only when the garden was too dry for the plants to bear. And I was surprised at how little water a garden can get along on.
Now I have a hose, and I don't use it all that much. I still rely on a rain barrel, and water only in August, when the days are blistering and the plants look close to wilting. And then I water deep.
One or two good soakings each week will do more for an August garden than daily sprinkling. And, in fact, daily sprinkling can do more harm than good.
If you soak the soil, the water will get down deep, where the plants need it,and the soil will be able to hold it there longer. If you just sprinkle, the sun will evaporate a lot of the water, and the plant will never develop strong, deep roots to reach for underground water. Instead, they'll send their roots up to the surface for the little water that's there. And that will weaken the plants and make them more dependent on you, and less able to survive dry spells.
The best time to water a garden is still a matter of personal preference, but the worst time has been established. It's high noon, when the sun quickly evaporates water, and when drops of water can act like magnifying glasses to burn tender leaves.
The cool of the day, whether moring or evening, is better. Evening people say their system gives plants more time to absorb water before the sun begins its evaporation. Morning people say evening watering sets plants up for insects and diseases by keeping them wet all night. They claim that morning water gives the plants moisture when they need it - in daylight - and gives them time to dry out by nightfall.
I tend to agree with the morning school, but if it's a hard, hot day, or if the sun gets too high before I get a chance to water, I'll do it in the first cool of the afternoon.
Some people get around the problem by sinking large coffee cans between thirsty plants. They punch a few holes in the cans, and at watering time, the simply fill them. The water drains into the soil slowly, soaking it.
You can use recycled water for a garden too, but you have to be careful. You want to keep laundry water with synthetic detergent and chemicals out of your garden. Stick to using wash water with pure, biodegradable soap, waters from washing and cooking vegetables leftover teas, and even bath water, if you feel like carrying it out.
You can use recycled water straight or add it to your rain barrel.