Monday, January 11, 2010

How and When to Water Your Plants?

Recent studies have confirmed that water on the leafs of plants can cause sun damage, as the water droplets focus the light rays, causing burns (see here). Thus, you should avoid spray watering your plants, especially here in the Arizona desert, which has intense sunshine due to the low humidity.

Hands down, flood irrigation is the best watering technique for the desert. Build an earth wall berm around the outside of your growing area, then just flood it with water. Be careful not to overflow the berm wall, as a little leak over the edge will quickly erode a huge hole in the wall.

For the most efficient use of water, irrigate in the evenings, to avoid excess evaporation.

You can do day-time flood irrigation during the heat of the summer to cool off the ground. I have kept tomatos going all summer long, in full Arizona sun, by heavy flooding and intentsive plant spacing. The intensive spacing creates a shaded zone under the plants, which along with the water, helps the plants survive the brutal heat.


  1. This is good information, especially this time of year. Have you tried sunken beds for vegetable plantings? I've read a bit about it but have not tested it yet. Fits well with your flooding technique.

  2. Hi Jan. Sunken beds would be great for heat-resistance purposes. I have never done them, though, mainly because it involves moving so much earth. Plus, I want to keep the nutrient rich topsoil in place.

    Well, maybe "nutrient rich" is giving our hard pan too much credit, but if there is any nutrients in there, I'd hate to lose them!

    The other drawback to sunken beds is just digging down that deep in our concrete-imitation soil. If I losen it up a full 8 inches down I feel highly accomplished!