Most vegetables, like most plants, need water to thrive. They have to have water to absorb nutrients so they can produce leaves, flowers, and fruits, as well as bulk up the stems and roots. If they lack water, they will not grow to their full potential and not produce the vegetables that you are hoping for. If they have too much water the soil will not have the air the roots need and the roots may rot. Some vegetables like lots of water while others do best if the soil is a bit on the dry side. And any given plant needs more water at certain times of its life cycle that at others. The key is to provide the right amount of water at the right time.
The amount and frequency of watering the vegetable garden depends on several factors:
1. Soil Type. Sandy soils need more watering than heavier soils because the water runs through them quickly. Soils high in clay or organic matter stay moist longer than sandy soils and will not need to be watered as frequently.
2. Slope. A garden that is on a hillside or slope will dry out more quickly than one on flat land. On the other hand, a garden that is on the bottom of a hill may accumulate water and be very wet. If water sits on the surface of the garden bed for more than 30 minutes you can anticipate problems growing many crops unless you take steps to drain the area.
3. Temperature. Plants will loose more water when temperatures rise so be prepared to water more frequently especially when temperatures are ninety degrees and more.
4. Humidity. Low humidity cause plants to lose water more easily especially when combined with high temperatures.
5. Growth Stage of the Plant.
Germinating seeds and seedlings are delicate and have shallow root systems so they need to be watered gently and frequently (about once a day).
If you transplant seedlings to the garden, their root systems will be damaged and will need time to recover so water them at least to the depth of 6” or so every couple of days.
Once plants have become established, water them deeply, more than 6” deep, to encourage their roots to grow down into the soil where they will not dry out when drought exists.
Each kind of vegetable has a time when watering is especially critical. This is often during the time that the edible part of the plant is forming or developing but there are exceptions. Here is a brief list of common vegetables and their critical period of watering; keep them evenly moist during their critical state.
| Crop | Critical Stage for Proper Watering |
|---|---|
| Beans, snap | Flower and pod formation |
| Beet | Seedling through root formation |
| Broccoli | Head formation |
| Cabbage | Head formation |
| Carrots | Seedling through root formation |
| Cauliflower | Head formation |
| Corn | Silk, tassel, and ear formation |
| Cucumber | Flower and fruit formation |
| Eggplant | Flower formation through harvesting |
| Melon | Fruit set and early development |
| Onion | Bulb enlargement |
| Pea | Flower formation and seed enlargement |
| Pepper | Flower formation through harvesting |
| Potato | Tuber set and enlargement | Radish | Seedling through root formation |
Squash, summer and zucchini |
Bud and flower formation |
| Tomato | Flower formation through harvesting |
| Turnip | Root formation |
Here are some guidelines for watering:
1. Most vegetables need at least 1” of water per week and Mother Nature rarely provides that during the summer months. Watch you local weather report on TV and they will probably report the amount of rainfall immediately after it comes and if a week goes by with less than 1” consider watering.
2. To determine if the soil is moist is to dig down 4” with a shovel or trowel and feel it. If it is dry, water.
3. Look at your plants; if they are wilted, water them.
4. Water in the morning if possible so that the leaves can dry before nightfall and avoid fungus diseases. Morning watering also saves on water costs as less water will evaporate back into the atmosphere rather than entering the soil and plant.
5. Watering twice a week giving ½ of the total water needed each time.
6. A deep watering is much better than shallow watering. The goal here is to encourage the roots to grow down deeply rather than remain in the top couple of inches where they will dry out easily. The leaves can block the descent of the water into the soil so don’t stop watering as soon as the leaves are wet. Just getting the foliage wet does not help the roots or intake of nutrients (although it does cool off the plant, not nothing when temperatures are over 90o).
Different vegetables like different watering techniques. For example, lettuce and other greens like to be cooled off with a spay of water and overhead watering does not hurt them. Tomatoes, on the other hand, may develop fungus on the leaves if water accumulates on the leaves from overhead watering. Some crops like squash have such large leaves that little water reaches the roots. Check the plants after a rain or watering and make sure they are getting what they need.
