Watering In Minutes or Hours Hard to Interpret

Readers Thompson seedless grape cupped leaf

Q. My property is in the shape of a pizza slice so I have tons of room in my back yard. I have a dwarf peach tree, Utah Sweet pomegranate, Valencia orange, Thompson seedless grape, and Flame seedless grape. The past couple of years I have been using drip system along with all my other backyard foliage. I used to water once per week for an hour during the winter, three times per week during the spring and fall for an hour each, and an hour per day during the summer. My fruit production was okay, nothing special. I have now switched from drip to watering with a hose.

            Do you have any suggestions for watering my fruit trees?  I have also found that my Thompson seedless grapes have been turning up in brown and some of the leaves have also been curling in. I attached pictures of both issues. What do you think could be my problem?

A. This seems to be the year for grape problems. Grapes do wonderfully well in our climate as long as the soil is prepared well at the time of planting, they get adequate amounts of water frequently enough and you cover the surface of our soil with organic mulch.

Red Flame grape at the Orchard

            Some people believe grapes should struggle to produce a quality crop of grapes. Believe me, in our climate and in our soils they struggle enough without imposing additional struggles. To get good grapes, keep them healthy and don't let them struggle under our circumstances.

            We did have some strong winds earlier that can cause the kind of damage you mentioned and that appear in the picture you sent to me. Watch the new foliage as it emerges. If it looks healthy, don't worry about the older foliage. That is old damage that was just temporary.

            You talk about watering over a certain length of time. This is like me asking you how many minutes of coffee or tea you drink. Or, if you don't drink coffee or tea, whatever beverage is your favorite. We don't talk about minutes or hours when we talk about drinking something. Likewise, when we give plants a “drink of water” we should not be talking about time but instead the volume of water we apply.

            I don't know how many drip emitters you have and I don't know how much water each one delivers in an hour. So I am going to guess you have four emitters for each tree and they deliver 4 gallons of water in an hour. This would mean that in one hour these trees would receive 16 gallons. For a medium-size tree, this is far too little.

Drip irrigation on grapes on the ground with mulch

            When watering with the drip system it should run for a long period of time, in some cases two or three hours. You will double the amount of water to these trees if you increase your watering from one hour to two hours. I would try this first.

            Drip irrigation is extremely accurate in applying the water. Much more accurate, efficient and consistent than using a hose.