Critical Periods of Water Usage for Selected Vegetable Crops

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Crop	Most Critical period(s) of water need

Carrot Radish Turnip Onion (dry) Snap Bean Pepper	Root enlargement Root enlargement Root enlargement Bulb enlargement Pod enlargement Vegetable growth (planting to fruit set)
Tomato	Early flowering, fruit set and enlargement. For mechanical harvesting, withhold water during latter part of fruit ripening period.
Cabbage Cucumber Lettuce Eggplant Asparagus Sweet corn Potato Broccoli Lima bean Cauliflower Cantaloupe Pea Spinach Sweet potato Watermelon	Head development Fruit enlargement period Head development Flowering and fruit development Plant development (brush) following harvest Silking and tasseling, ear development Tuber set and tuber enlargement Transplant and flower bud initiation Blossom and pod enlargement Transplant and curd development Vining, pollination and fruit enlargement Pod development Through out growing season Slip setting (planting) Vining, pollination and fruit enlargement

Notes:
Crops from which leaves are harvested, especially those with short growing periods, need a generous supply of available water from planting to harvest. Plants that develop heads need a uniformly adequate water supply, especially during head enlargement of these plant parts. Root, tuber and bulb crops need water the most during tuber set and during periods of enlargement of these plant parts. Crops from which fresh or dry seeds, pods, or ears are harvested need adequate water supply at flowering (or tasseling) and fruit set. These crops also need an adequate water supply during fruit, seed, pod, or ear development to prevent fruit cracking and malformed ears or pods.

Adapted from: The Vegetable Gazette Vol. 3(7) June 1999 by Bill Lamont and, The Texas Commercial Vegetable Production Guide by Frank J. Dainello.