Some Vegetables Require Less Water than Others
a 2011 Interview with Jim Myers, Professor of Horticulture Oregon State University
Gardeners who want to save water with wise irrigating techniques might consider an unusual approach: plant crops that don't require much water in the first place.
"Some vegetables, such as beans, are adapted to drought conditions at a very basic, cellular level," explained Jim Myers, professor of horticulture at Oregon State University. "Tepary beans grow successfully in desert and near-desert conditions. They are native to the American Southwest and have been a staple food crop there for hundreds, or probably thousands, of years. I have grown them successfully in Oregon."
Beans in the cowpea group, such as the familiar black-eyed pea, also have this characteristic. The black-eyed pea needs little water and grows poorly if watered too much. "However," Myers said, "the cowpea beans need heat to mature, and our cool nights can limit growth and reduce seed set. The same is true for okra."
Some common beans, like snap beans and pole beans, require a short growing season and can set a crop on small amounts of moisture. Tomatoes, squash and melons establish deep root systems quickly and can draw moisture from the deeper soil long after the surface has become dry in midsummer, Myers said. "There's also a zucchini variety (Dark Star) bred for its ability to grow under dry-land conditions with roots that seek out the water table."
"As long as these vegetables have water early in their growing season, they tolerate drought," Myers said. "In fact, many tomatoes actually do better if you cut off irrigation in mid- to late summer." Cutting the water also reduces the ability of certain fungal and bacterial diseases to take hold.
By and large, cool-season crops are not drought-resistant. These include cool-season legumes such as peas, lentils and fava beans, and the crucifer crops: Brussels sprouts, cabbage, cauliflower, collards, kale, kohlrabi, mustard, broccoli, turnips and watercress. Sweet corn and lettuce are shallow-rooted and don't do well without a lot of water.
In addition to using well-known water-saving techniques such as drip irrigation and mulching, try grouping your vegetables according to their water needs. In general, give your vegetables no more water than they need – rather than as much as they can withstand.
Master Gardeners throughout California did a lot of research on this topic, especially during the drought of ten years ago. Their criteria: seed catalogs that used the terms drought-resistant or drought tolerant in the variety descriptions. One good rule of thumb: consult seed catalogs or nurseries in dry climate areas. Next time you visit Las Vegas, Reno, or Phoenix, drop by a local nursery and ask questions!
Here’s that Master Gardener list of drought resistant crop varieties from UCANR:
BEANS
BUSH BEANS
Pinky Popcorn
Silver Queen Hybrid Sweet
Hill Country Heirloom Red
Jing Orange
White Half Runner Snap
BUTTER BEANS
Tennessee Red Cob
PEPPER
Jackson Wonder Bush
GARBANZO BEANS
COWPEAS - need warm nights
Pink-Eye Purple-Hull
Jupiter Red Bell
Ordoño
Ceci
LIMA BEANS
QUINOA - all varieties
Alabama Black-Eyed Butter
Armenian
Carolina Sieva
Lemon
SQUASH
Christmas
Cocozelle Zucchini
Fordhook 242 Bush
EGGPLANT
Costata Romanesco
Henderson Bush
Listada de Gandia
Cushaw Green-Striped
Jackson Wonder
Dark Star Zucchini
Pima Orange
GRAINS
Iran
Willow Le
AMARANTH
Jumbo Pink Banana
POLE BEANS
Mayo
Lebanese Light Green
Blue Coco
Red Stripe Leaf
Garden of Eden Romano
Tampala
SUNFLOWER
Louisiana Purple Pod
BARLEY
Skyscraper - edible seed
McCaslan Snap
Ethiopian Hulless
Rattlesnake
Jet
TOMATO
Selma Zesta
Milan
Caro Rich
Selma Zebra
Pearson
TEPARY BEANS - need warm
HERBS
Pineapple
nights
Basil - Mrs. Burns’ Lemon
Stone
Big Fields White
Borage
Yellow Pear Cherry
Black
Catnip
Blue Speckled
Chamomile, German
WATERMELON
Brown Speckled
Chives
Black Diamond
Cocopah Brown
Hyssop
Colonia Morelos Speckled
Lavender
WHEAT
Mitla Black
Lemon Balm
Hard Red Spring
Pinacate
Mullein
Kamut
Sacaton Brown
Oregano
Vaughan Turkey
Tohono O’odham White
Rosemary
White Sonoran
BROCCOLI
Sage - once it’s established
Sweet Marjoram
Waltham 29 - when fall planted
Thyme
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CHARD - Almost all varieties listed
MELON
Iroquois
Navajo Yellow
MUSTARD
Daymon Morgan’s Kentucky
Butcher
Southern Giant Curled
Hopi Pink
Painted Mountain Flour
OKRA - needs warm nights
Gold Coast
In personal experience, there are some varieties of drought tolerant summer garden staples - tomatoes and zucchini - that, with a bit of protection from late afternoon sun and heat, can survive and thrive will less water. Dark Star zucchini, according to research done at Oregon State university, can get by with less water. And, it works here in the hot Central Valley as well. I have also fallen in love with the idea of growing an early ripening determinate tomato variety, Bush Early Girl, as one of the first to plant in early April. Since it is a determinate variety, it tends to set and ripen its fruit at the same time. I’ve been harvesting ripe tomatoes from that plant since mid-June. When most of the crop is gone, I will take it out.