Friday, June 15, 2012

Water Vegetables Properly by Carol King

Drip Systems are best for watering vegetables. Photo courtesy of University of Mississippi
As if growing vegetables in Colorado weren't hard enough, did you know each vegetable has different water needs?  Watering your vegetables properly during the growing season is directly related to produce quality and yields.  Most vegetables use around quarter-inch of water per day during typical summer weather.  If the garden is watered every four days, apply one inch of water per irrigation.  Hot, windy weather will increase water demand significantly.   Many vegetables become strong-flavored or stringy with water stress.

CSU provides this list of  some critical watering needs for selected vegetables:
  • Asparagus needs water most critically during spear production and fern (foliage) development.  Less water is needed after ferns reach full size.

  • Cole crops (broccoli, cabbage, cauliflower, collards, Brussels sprouts, kale, and kohlrabi) need consistent moisture during their entire life span.  The quality of cole crops is significantly reduced if the plants get dry anytime during the growing season. Water use is highest and most critical during head development.

  • Beans have the highest water use of any common garden vegetable.  During blossoming and fruit development, beans use one-quarter to over one-half inch of water per day. Blossoms drop with inadequate moisture levels and pods fail to fill. On hot, windy days, blossom drop is common.  When moisture levels are adequate, the bean plant is a bright, dark, grass-green.  As plants experience water stress, leaf color takes on a slight grayish cast.  Water is needed at this point to prevent blossom drop.

  • Carrot and other root crops require consistent moisture.  Cracking, knobby and hot flavored root crops are symptoms of water stress.

  • Corn water demand peaks during tasseling, silking, and ear development.  Water stress delays the silking period, but not tasseling. Under mild water stress, the crop may tassel and shed pollen before silks on ears are ready for pollination.  The lack of pollination may result in missing rows of kernels, reduced yields, or even eliminate ear production.  Yield is directly related to quantities of water, nitrogen, and spacing.

  • Lettuce and other leaf vegetables need water most critically during head (leaf) development.  For quality produce, these crops require a constant supply of moisture.

  • Onion family crops require consistent moisture and frequent irrigation due to their small, inefficient root system.

  • Peas need water most critically during pod filling.

  • Potatoes tubers will be knobby if they become overly dry during tuber development.

  • Tomato family (tomatoes, peppers, and eggplant) needs water most critically during flowering and fruiting.  Blossom end rot (a black sunken area on the bottom of the fruit) is often a symptom of too much or too little water.  The tomato family has a lower water requirement than many vegetables and plants are often over-watered in the typical home garden.

  • Avoid overhead watering. Photo courtesy of Laura Berman
  • Vine crops: cucumbers, summer and winter squash, and assorted melons need water most critically during flowering and fruiting.  Vine crops use less water than many vegetables and are often over-watered in the typical home garden.
Here's a complete guide to proper vegetable watering.