Everything is more expensive this year, and that likely includes utilities like your water bill. While growing vegetables in your yard can be enchanting and empowering, it isn’t very efficient (compared to farms) in terms of water usage. There are a number of ways to become more efficient and sustainable, including using drip irrigation, but another way is to only plant vegetables that don't need too much water to begin with.
Watering at the root is key
Before I get to the specific vegetables, it's important to go over a few general watering tips.
Remember that vegetables get hydration through their roots, which live underground. Watering from above, like a hose or sprinkler, has problems: you’re getting the plants wet more than the roots, which creates conditions for disease spread; you’re watering less precisely, therefore wasting water; and the impact of the water against the dirt causes droplets to bounce back up with whatever fungus or viruses are in the dirt, also spreading disease. Watering gently and consistently at ground level with drip irrigation is the best option for both the plant and your wallet.
To ensure you’re watering efficiently, group plants with similar watering needs together in your garden, so you can set the drip appropriately to water less.
But even more important is remembering that roots grow over time. A new seedling has shallow roots, whereas an end-of-season plant has deeply established roots. More roots means that the plant can absorb more water from deeper underground. Less roots means less hydration from the soil, so more water is needed at a shallower depth. (Though some vegetables, like corn and lettuce, will always be shallow rooted, and thus aren’t good candidates for less water.)
Hothouse plants
According to Oregon State University, a tomato plant's need for watering is negated by the deep roots the plants establish over the season. As above, you want to water sufficiently early in the season as roots are established while taking care not to over water, which will result in those roots staying close to the surface.
If the plant needs water, those roots will grow deeper in search of moisture. Reducing water greatly, if not cutting it off entirely mid-season, shouldn’t harm your harvest. The lack of surface water will reduce disease spread, and tomatoes will ripen if you reduce their watering. It’s not only tomatoes, either: Squash, which includes zucchini, summer and winter squash, as well as melons, eggplants, and hot peppers all behave the same in terms of water needs and roots.
Beans
Most beans, particularly pole beans, have adapted to drought conditions over time. As such, they can survive and produce flowers and fruit with minimal moisture. Beans require water to germinate, so if you direct sow, ensure the seeds have consistent moisture levels. Once germinated, you can reduce (but not eliminate) water. Since beans have such a short season (usually 60 days or less), they require less water simply by existing for less time. Less moisture is going to reduce common bean problems like powdery mildew, a quickly spreading surface fungus.
Chard and okra
For some heat hardier vegetables like chard and okra, they still require water, but do better with weekly or every-other-weekly deep watering, as opposed to daily drip. Okra is native to drier climates and prefers less water. The deep roots of the plant allow it to draw enough water from the soil to sustain itself. Chard and kale can use their huge leaves to shade the ground, which is an effective form of moisture retention. Occasional deep waterings will be enough for the plant to continue growing.
Blueberries prefer less moisture
I know, blueberries are a fruit and not a vegetable, but I felt compelled to include the advice here anyway. Consider it a bonus tip.
A few years ago, Micah Geiselman, a blueberry farmer from Morning Shade Farm in Canby came to inspect my many bushes, and he had surprising advice: “People over-water their blueberries,” he explained to me. They appreciate good drainage and do better with less water.
I’ve since changed the elevation of my blueberries to ensure better drainage and moved watering lines further away—the results were astounding. I experienced better yields, but the berries themselves were plumper and better tasting. This isn’t conclusive, of course, since there are too many variables to account for, but I take the advice of a blueberry expert seriously.
