Timing can be important when watering vegetables

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Close-up of a sprinkler.
Watering during the early morning hours has several advantages. (Photo by Lynn Ketchum.)
Last Updated: 
June 17, 2010

EUGENE, Ore. – Watering your vegetable plants is critical to plant health on a day-to-day basis. There are also certain periods in a vegetable plant's life cycle when moisture is most critical for the formation of the most robust, best-quality produce, explained Ross Penhallegon, horticulturist with the Oregon State University Extension Service.

There are day-to-day strategies, he said. First, study the appearance of your plants, not the soil.

"Wilting during the day, slow growth, or dull green color are the best indicators that plants are thirsty," said Penhallegon. "Just because the surface of the soil is dry doesn't mean plants need water. But, if one to two inches of soil is dry, chances are a watering is needed."

Watering during the early morning hours has several advantages. There is less wind to affect the soaker hose, drip or sprinkler pattern. Plus, the temperatures are lower in the early morning, meaning more water gets into the soil and doesn't evaporate away.

If you are on a community or city water system, pressure is usually better in the early hours, so you can cover more area with your watering.

During hot summer days, plants will wilt severely on a hot afternoon. In that case, water them to revive them. Plants are not usually injured by watering in the heat of the day, but some plants may be burned by water remaining on leaves in bright sunlight.

If you have an automatic system, anytime between 5 a.m. and 10 a.m. is a good time to irrigate.

"Avoid water application in the late afternoon, so that the plant foliage is dry going into the night," suggested Penhallegon. "The less the foliage is wet the smaller chance there is of plant disease problems on turf, vegetables, or flowers."

Penhallegon says there also are season-long watering strategies and different vegetable types need adequate water, especially at certain, more vulnerable stages in their lives. Among them:

  • beans - during flowering and pod development;
  • broccoli, cabbage and other cole crops - during head formation and enlargement;
  • carrots and other taproot vegetables - from germination until harvest;
  • corn - from tassel to silk and ear filling;
  • cucumbers - during flowering and fruit development;
  • eggplants - from blossom set through fruit enlargement;
  • lettuce and other leafy vegetables - from germination until harvest;
  • onions - during bulb formation;
  • peas - during flowering and pod filling;
  • peppers - from blossom set through fruit enlargement;
  • potatoes - from blossom time until harvest;
  • tomatoes - from blossom set through fruit enlargement.
Author: Carol Savonen