Some Vegetables Require Less Water than Others

Some Vegetables Require Less Water than Others

a 2011 Interview with Jim Myers, Professor of Horticulture Oregon State University  

(From: http://extension.oregonstate.edu/gardening/some-vegetables-require-less-water-others )

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. 

More information about the low-water use vegetable varieties mentioned here:
Tepary Beans
Cowpeas
Black-eyed peas
Snap beans
Pole beans
Dark Star zucchini

Other heat-tolerant vegetable varieties, according to Southern Exposure Seed Exchange:

Green Pod Red Seed beans
Lima Beans (butterbeans)
Tropic VFN tomato
Ozark Pink VF tomato
Neptune tomato
Listada de Gandia eggplant
Black Beauty eggplant
Ping Tung Long eggplant
Carolina Wonder pepper
Charleston Belle pepper
Aji Dulce pepper
Little Leaf H-19 cucumber
Ashley cucumber
Suyo Long cucumber
Moschata-type summer squash
Tromboncino summer squash
Waltham Butternut winter squash
Seminole pumpkin
Missouri Gold melon
Top Mark melon
Sweet Passion melon
Kansas Melon
Edisto 47 melon
Crimson Sweet watermelon

Strawberry watermelon
Gold Coast okra
Stewart Zeebest okra
Beck's Big Buck okra

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.