In the vegetable garden, an even supply of water throughout the growing season is directly related to the garden's quality and yield of vegetables harvested. Generally, vegetable demand for water is high during 1) the first few weeks of growth following germination, 2) right after transplanting, and 3) during flowering and fruit development.
However, with each vegetable crop there are particular developmental stages when having a good supply of water is critical.
- Asparagus- during fern development and growth after harvesting. Drought stress during the growing season can reduce harvest yields the following year.
- Broccoli, Brussels sprouts, cabbage, cauliflower and kohlrabi - during head development. Drought stress during periods of high temperatures is a contributing factor to bolting (premature flowering).
- Beans & Peas- flower bud formation to pod enlargement. Too little water can cause flower or pod drop, or poor seed fill within the pods.
- Beets, carrots and other root vegetables - root enlargement. Cracking, knobby growth and hot flavor can all be symptoms of dry growing conditions.
- Cucumbers and other vine crops - fruit enlargement. Drought stress can cause flower or fruit drop, and blossom-end rot in cucumbers, summer squash and melons.
- Eggplant, pepper and tomato - flowering, fruit set and enlargement. Drought stress can cause flower or fruit drop, and blossom-end rot.
- Lettuce (crisphead, butterhead, leaf or bunching and romaine) - head enlargement or leaf growth. Dry conditions can stunt plant growth and reduce head quality. Drought stress contributes to bolting (premature flowering).
- Onion and related crops - due to a small, and relatively inefficient root system onions require even soil moisture throughout their growth. Early water shortages will limit leaf growth and will effect later bulb enlargement. Dry conditions during bulb enlargement also effects size development.
- Potato - tuber set and enlargement. An uneven supply of water will cause tuber defects such as hollow heart, knobbiness and splitting.
- Sweet corn - tasseling, silking and ear development. Drought stress during tasseling and silking results in poor pollination, few kernels on the ears, small ears or poor development of the tips of the ears. A lack of moisture during ear development will decrease yield, reduce quality and effect flavor. Sweet corn yield is directly related to quantities of water, nitrogen and spacing.
When plants are healthy and growing with plenty of moisture, their leaves are bright green with firm stems and fully extended leaves. This can serve as a visual clue to a plant's condition. Water stressed plants often develop a grayish-green coloration and often show visible wilting.
As a general rule, vegetables perform best with an even amount of moisture throughout the growing season, typically one inch of water per week. As summer conditions get warmer and drier, providing moisture through irrigation will be needed to keep your crops growing well. This is especially true for plants heavily loaded with fruits.
Finally, the use of organic mulches provides several benefits in the vegetable garden, including suppression of weed growth, moderation of soil temperatures and preservation of soil moisture. Covering the soil with mulch also prevents rain splash of soil and fungal spores onto plant leaves, which is often the first step in disease development.
Photo Descriptions
Cracking, knobby growth and hot flavor can all be symptoms of dry growing conditions in root crops like carrots, beets, turnips, etc.
Misshapen or bottle-neck cucumbers can be caused by pollination problems or growing conditions which are too dry.