Most fruits and vegetables require one inch of water per week during the growing season.  Sprinklers are a great backup to natural rainfall, but how long do you turn them on to get that precious inch?  How do you know if your garden is being evenly watered?

Last year, I learned that it's best to situate your sprinklers so they provide head to head coverage, but that trick isn't enough to ensure even watering with an irregularly shaped garden.  Instead, you'll need to put your sprinklers where you think they should go, then run some irrigation tests.  Scatter empty containers every few yards across the garden, blast the sprinklers for an hour, then go back and measure the amount of water in each container.

To help you visualize wet and dry spots, draw a rough map of the garden and write in the water depth at each container location.  Do a bit of math to figure out the average water depth across the garden, then circle areas which ended up with less than average water.

Now it's time to move the sprinklers a bit to make those dry spots go away.  If you're lucky, you will have noticed an abnormally wet spot on one side of a sprinkler and an abnormally dry spot on the other side.  In this case, you can simply move the sprinkler a few feet closer to the dry spot and away from the wet spot.

On the other hand, you may simply have too few sprinklers in play.  If there are dry spots at the outer limits of two sprinklers, you may need to add a third sprinkler to fill in the gaps.

Once you move the sprinklers, run another irrigation test and repeat the process until your garden is getting the same amount of water in every container.  I chose to stop tweaking the sprinklers once the containers were all within the same ballpark --- how obsessive you get about this is up to you.

It will take a few hours of your time to get the sprinklers set up properly, but the irrigation tests are well worth the work.  Now your garden will be evenly hydrated, and you will even know how long it takes to provide that critical inch of water.  Due to different sprinkler orientations, I figure I need to run each set of sprinklers for three hours to get an inch of water in the upper garden and for two hours to get an inch in the mule garden.  I guess it only took three and a half inches of water to saturate that hydrophobic compost --- not nearly as bad as I thought.

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About us: Anna Hess and Mark Hamilton spent over a decade living self-sufficiently in the mountains of Virginia before moving north to start over from scratch in the foothills of Ohio. They've experimented with permaculture, no-till gardening, trailersteading, home-based microbusinesses and much more, writing about their adventures in both blogs and books.



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