Q: I’ve decided to use drip irrigation for my tomatoes this spring. Any advice on how many gallons per hour, how often, where to locate the drip hose , etc?
A: Water specifications depend a lot on your personal observation. A tomato, like any plant, uses water depending on how hot it is, how big it is, how windy it is, etc. Beside that, you have to consider your soil type. Water in clay soils percolates down in a “turnip” shape : wide at the top and narrow at the bottom. In sandy soil, water disperses more in a “carrot” shape. I’d run the main supply hose along the row and put two one-gallon-per-hour emitters at each plant, one on each side, six inches from the stem. When the plants are less than 18″ tall, run the system 30 minutes every three days. As they get bigger, increase the run time. By mid-summer the tomatoes might need two hours every three days. Avoid watering every day: the soil should dry a bit between irrigations. Look for droopy leaves in mid-afternoon to determine when to increase your watering.