Warm summer temperatures prompt vegetable crops to grow and thrive. Keeping garden vegetable crops hydrated is crucial for these plants thriving as water is essential to the photosynthesis process, plant growth, and production. When water availability is reduced, carbohydrate production in the plant, the building block of plant nutrition, decreases significantly. That decrease leads to reduced growth, vigor, and crop production potential.
Here are some very simple tips to help provide the needed moisture levels in vegetable and fruit crops.
Provide an evenly moist seed bed for direct seeded crops through the stage where the first two true leaves have emerged. This tip will help plant roots become established to start pulling in moisture and nutrients for the growing season.
Transplanted crops need to be watered to keep the roots and leaves hydrated to avoid plant wilting during the establishment and production phases. Watering with drip irrigation or soaker hoses will help place the water at the base of the crops to reduce water loss and reduce the spread of blight by not moving foliar bacteria with overhead irrigation.
Place organic mulch sources that are free of pesticide residue between plants to help keep soil cooler and reduce soil moisture evaporation.
Water in the morning when the wind is down or in early evening to maximize the amount of water that reaches the intended crops.
Maintain consistent moisture levels for each crop, not allowing the soil to dry out or become soggy. This tip helps reduce incidence of blossom end rot in tomatoes and bitter or watery tasting cucumbers.
Watering small fruit crops will vary between crops and their specific needs. In general, 1 to 1.5 inches of water per week is needed for plant growth and especially during fruit establishment.
Fruit trees require a high level of water use, especially during fruit set and development. Deep, slow, trickling watering sessions under the canopy and beyond of each tree is needed every couple of weeks this summer and into fall. If a gardener can shove a screwdriver into 12 inches of moist soil, the irrigation has been adequate.
Know the difference between moisture needs between vegetable and fruit crops. Below is a chart explaining the essential irrigation periods for various vegetable, small fruit and tree fruit crops from Water Wise: Vegetable and Fruit Production by the University of Nebraska-Lincoln Extension.
Table II. Critical periods for irrigation of vegetables, tree fruits, and small fruits.*
Vegetable Crops
Critical Period(s)
Asparagus
Spear growth, fern growth
Broccoli
Transplanting, flower bud production
Cabbage
Transplanting, head development
Carrot
Root enlargement
Cauliflower
Transplanting, curd development
Cucumber
Pollination, fruit enlargement
Eggplant
Transplanting, flowering, fruit development
Lettuce
Throughout growth
Lima bean
Blossom and pod development
Muskmelon
Pollination and fruit enlargement
Onion
Transplanting and bulb enlargement
Pea
Pod development
Pepper
Fruit development
Potato
Tuber development
Rhubarb
Petiole formation for harvest
Snap bean
Blossoming and enlargement
Spinach
Throughout growth
Sweet corn
Silking and tasseling ear development
Sweet potato
When slips are set in the field
Tomato
Transplanting, early flowering, fruit set, enlargement
Turnip
Root enlargement
Watermelon
Pollination and fruit enlargement
Tree Fruits
Critical Period(s)
Apple
Early fruit set, flower formation, final fruit swell
Pear
Early fruit set, flower formation, final fruit swell
Peaches
Early fruit set, flower formation, final fruit swell
Plums
Early fruit set, flower formation, final fruit swell
Nectarines
Early fruit set, flower formation, final fruit swell
Cherries
Early fruit set, flower formation, final fruit swell
Small Fruits
Critical Period(s)
Blueberries
Berry swell to end of harvest and bud formation for next year’s crop (late July and August)
Raspberries
Bloom and as berries are sizing before first picking
Blackberries
Bloom and as berries are sizing before first picking
Strawberries
At planting, during runner formation, during flower bud formation before harvest, and at renovation
*Used with permission from Dr. William Lamont, Pennsylvania State University Extension.
Source: Water Wise: Vegetable and Fruit Production
