Water efficient vegetable gardening is a requirement in hot, dry West Texas. We have minimized our water use by choosing raised beds utilizing a drip-irrigation grid and hardwood mulch. The three raised beds in our back yard are planted to maximize sun for tomatoes, black-eyed peas, okra and sweet peppers in the largest bed. The medium bed has cherry tomatoes, cucumbers and scarlet runner bean. The smallest bed is also the shadiest and contains rainbow chard and eggplant.
Raised Bed Design
The raised beds are constructed of 1 inch thick cedar boards and are lapped and screwed with heavy duty wood screws. They are 10 inches deep. The beds were staggered in length with the longest bed 16 feet by 3 feet wide, the middle bed 14 feet by 3 feet and the short bed 12 feet by 3 feet. We have a significant slope in the back yard. The longest bed was leveled when installed about 10 feet from the fence at the bottom of the slope. The middle and top (short) bed were also leveled when installed. We left 3 feet between beds and put 4 inches of mulch as a walkway between beds. The staggered design also allows better maneuverability for our garden wagon between the beds.
Water Efficient Drip Irrigation
The drip irrigation in all three beds is on a single watering station tied into the automated sprinkler system. To better control the amount of water and to allow automated watering to designated beds, a shutoff valve was installed in each bed at the beginning of the ½ inch drip irrigation hose in a modified grid. There really isn’t a limit to the number of shut off valves that can be installed in an irrigation grid. This means that we could add an additional shutoff valve and water only a portion of a bed by leaving the first valve open and closing the additional valve.
All three raised beds use ½ inch polyethylene drip irrigation emitter tubing. Drip irrigation emitter tubing has 1 gallon per hour pressure compensating emitters spaced every 12 inches. Arranged in a modified grid pattern, you can seed and space your vegetables to take advantage of the water from the emitter.
Currently, we use a modified grid with a single hose that is run about 6 inches inside the edge of the bed, looping at the end to come back down the middle of the bed and then looping again to run about 6 inches inside the other edge of the bed. The beds are 3 feet wide and this allows good water coverage. The coverage is improved, if you plant your seeds or seedlings to match the emitters.
Mulch, Mulch, Mulch!
Vegetables love water! Once your seeds are 3 inches tall, be sure to cover with 2 inches of mulch. As the seedlings grow, add more much stopping at 4 inches of mulch. This will eliminate the need to weed the garden beds and also will significantly reduce the amount of water needed.
In successive plantings, you will need to move aside the mulch mounding it up and then pushing it back as new seedlings grow. This is kind of a pain and it does require patience. However, the water savings and the ability of the seedlings to survive in hot dry conditions will more than reward your work.
Water Deeply and Not as Often
Drip irrigation works best when it is allowed to water deeply. This means running the irrigation for at least an hour. This allows each emitter to drip 1 gallon of water directly to the plants. The mulch will shade the roots of the plants and help to retain the water. Our drip irrigation configuration puts the emitter hose on top of the raised bed soil and it is then covered with 4 inches of mulch. See my post on Gardening In West Texas for an overview of the whole yard using drip irrigation and mulch.
Choose the correct Vegetable Varieties
Rainbow chard and Ichiban eggplant have shown themselves to be heat tolerant and to grow well in our upper garden that gets about 6 hours of sun daily.
The cherry tomatoes and cucumber thrive on 7 hours of sun in the middle bed. The cucumbers really require the water! They are Burpless and are supposed to be sweet. However, we have found that unless they are given lots of water, they are very bitter.
We choose Clemson spineless okra and tried red okra for the first time this year. Turns out that we love the red okra and we will be planting it every year. Red okra is not as furry and doesn’t sting when you pick it. It is also ‘softer’ and cooks beautifully.
We are still experimenting with tomatoes. Golden cherry tomatoes have produced very well, but they really aren’t sweet enough for me. The Sweet 100 cherry tomatoes are sweet, but they are having a very hard time with the heat. The Cherokee heirloom variety isn’t producing very well, but the fruit tastes great. Maybe the Cherokee will come through as the heat goes away in September.
Be Willing to Spray for Insects
Water efficient vegetable gardening is like all other vegetable gardening—there will be insects. The first year that we had the garden, we tried to be all natural and only plant marigolds to control garden insects. This didn’t work very well. Bugs consumed more of the vegetables than we did. We continue to plant marigolds (mostly because they are pretty) but we also are using organic sprays such as Neem oil, Take Down Garden Spray (chrysanthemum extract) and insecticidal soap. So far this year, we aren’t losing very many plants or produce to insects and we are happy with the organic sprays.
And Finally…
Water efficient vegetable gardening is very rewarding. We work in the beds early in the morning or late in the evening several times a week. The drip irrigation eliminates the need to hand water and we are very happy with the seeds that we planted on each emitter. The tomato seedlings and cucumber seedlings were also planted to take advantage of the drip emitters. With all the plants in place, we spend the majority of our vegetable garden time, harvesting the produce.
Looking better all the time. Wish I was there to sample some of the production. db
Wow great information