Are You Watering Your Veggies the Right Way?

hand holds red hose with clear stream water

Treehugger / Christian Yonkers

Everyone knows vegetables need water to grow. What they might not know is that vegetables need adequate water even after the plants have set fruit. Vegetables, after all, are mostly water. Consider, for example, the water content of these commonly grown vegetables, according to the USDA's FoodData Central:

  • Cucumbers: 97%
  • Lettuce: 96%
  • Tomatoes, radishes, celery: 95%
  • Cauliflower, eggplant, green cabbage, peppers (red and yellow): 92%
  • Broccoli: 89%
  • Carrots: 88%
  • White potatoes: 82%

Dani Carroll, a regional extension agent with Alabama Extension who specializes in home environments, gardens and pests, offered the tips below to help backyard gardeners ensure they are watering their vegetables correctly so all of the effort they put into their gardens doesn’t go to waste. These guidelines apply to winter and fall gardens as well as spring and summer gardens.

Water 1 Inch per Week

"This is a really good guideline," Carroll said. To help homeowners understand how to calculate how much water is needed to achieves this goal, she said "an inch of rain is 60 gallons per hundred square feet."

Collect and Measure Rain

close up shot of rain gauge in garden
Treehugger / Christian Yonkers

"I think a lot of people forget that a vegetable is really just vegetable-flavored water, and they neglect the water part of growing backyard vegetables," said Carroll.

Water Deeply

Apply water two to three times a week and water deeply each time as opposed to a brief, shallow watering every day. Watering deeply—moistening the soil to a depth of six inches is ideal—will encourage plants to send roots well into the ground. Deep roots help plants better sustain stresses caused by hot and dry weather.

Know Your Soil Type

man holding cup of dirt with two hands
Treehugger / Christian Yonkers

Collect rainwater. It's free and even contains beneficial trace nutrients, Carroll said. One way you can do this is with a rain gauge, which will also let you how much rain your garden is receiving and, therefore, how much you need to water.

While Carroll really likes the "inch" rule, she says knowing your soil type is critical to ensuring you achieve this goal. "If you have a sandy soil, the water is going to filter right through, whereas a clay soil is going to hold water." People who have sandy soils, therefore, will need to strive for more than an inch of water a week, Carroll said.

Have Your Soil Tested

various soils in glass containers outside in grass ready for testing

Treehugger / Sanja Kostic

Homeowners can send a soil sample to a state extension lab to have it tested to determine its texture. Soil sample kits are available at county extension offices. The results will also include information on the nutrients in your soil. Fees for the service vary by state. The cost is usually very small, but it can save homeowners a lot of money, Carroll pointed out. That's because knowing your soil nutrient content can help avoid the application of unnecessary fertilizers. "I soil test about every three years," she said. One reason for that is to know the soil pH. It's important to get this correct because pH controls how well plants take up nutrients.

Water Early in the Morning

You'll lose less water to evaporation by watering before the heat of the day sets in. If you get water on plant leaves, they’ll have plenty of time to dry, which reduces the chance of fungal and disease problems than if you water late in the day.

Use a Drip or Soaker Hose

You can apply water next to the plants where the water will seep deep into the root zones. You will also avoid watering between rows and in walkways, which wastes water and can promote weeds to grow. These are best on even ground. If you have uneven ground, you will likely get too much water at the end of the hose and not enough at the front end.

Use Drip Irrigation

A drip irrigation system in a garden
Drip irrigation allows you to control the amount of water your veggies get. Ryo Chijiiwa [CC BY 2.0]/Flickr

It's not just for commercial agriculture! Kits for use in home gardens are available online at very reasonable prices. This is a very efficient way to water because pressurized emitters can be set to water specific areas at pre-set rates. With these kits you'll know exactly how much water you're putting on your garden.

Water by Hand

A slow small stream of water is more efficient than a fast stream because a significant amount of water from a fast stream will run off and be wasted.

Use Mulch

There are a number of advantages to mulch. An ideal mulch is three inches thick. Mulch mediates the soil temperature, conserves water by preventing evaporation and holds down fungal diseases from rain that can splash fungal spores onto bottom leaves.

Remove Leaves That Don't Look Right

two hands cut plants with metal tool
Treehugger / Christian Yonkers 

Leaves of vegetable plants, particularly lower leaves, can experience many problems from water. Pull yellow or spotted leaves from the plants and dispose of them away from the garden. "Sanitation is one of the most important aspects of home vegetable gardening," Carroll said.

Choose the Right Fertilizer for Your Garden

hand tosses diy mulch to small outside tree at base

Treehugger / Sanja Kostic

Use water-soluble fertilizer if growing vegetables in a pot. If you forget to water the pot, granular fertilizers will just sit there. Granular fertilizers should be used in gardens, though. With drip hoses, you know granular fertilizers will get watered in, Carroll said.

Observe Your Plants

Guy bends to garden ground and snips plant

Treehugger / Christian Yonkers

They'll let you know if you're watering them properly. Wilted leaves are just one example of how plants "talk" to us. It's important to avoid these types of problems because they weaken plants. "I use drip hoses and drip irrigation, and how long I leave them on is pure observation," Carroll said.

Observe the Soil

hand with gardening tools and glass measuring cup collecting soil for testing

Treehugger / Sanja Kostic

Simply use a spoon or a trowel to see how deeply moisture has penetrated your soil. As mentioned, the ideal depth is six inches. The depth of your moisture will let you know if you've watered enough.

Don't Use a Sprinkler

Overhead watering can contribute to bacterial and fungal diseases. It can also result in wasted water because you'll lose a lot of that water to evaporation, you'll water pathways and rows, which can encourage weeds, and you'll spray nearby areas that don't necessarily need the water. "There’s no telling what you’re watering with a sprinkler," Carroll said.

Don't Water Late in the Afternoon

The foliage will likely stay wet all night, which can lead to fungal and disease problems.

Don't Water Shallowly

Daily shallow watering keeps roots near the top of the soil where they can easily dry out and cause the plants to wilt and underperform in producing vegetables. Exceptions are seed beds and transplants. Seeds need constant moisture to germinate and don't have roots, anyway. Transplants need consistent watering until they are established. Daily watering at first will help reduce transplant shock.

Don't Water Too Fast

man holds gushing water hose
Treehugger / Christian Yonkers

If you're hand-watering with a hose, avoid hitting your plants with a hard stream of water. "Many people think you shouldn’t do this because they're going to hurt the plants," Carroll said. That's not the case, she quickly added. The problem with watering too fast is that you'll have a lot of water that just runs off and winds up being wasted. Instead, use a steady small stream of water.

Don't Apply Granular Fertilizers Before Big Storms

People sometimes think it's a good idea to put out fertilizers before big storms because the rain will soak the granules into the soil. Actually, the opposite can happen. Downpours may wash them away!

3 of the Most Common Watering Mistakes

Carroll said home gardeners often make three mistakes when watering their vegetable gardens.

Overwatering Your Garden

"People think ... water, water ... it's wilting! ... It needs more water," said Carroll. "When you water too much, plants will actually get the same symptoms (wilting) as they would if you weren't watering your plants enough." The problem with too much water, she said, is that the plant roots can't breathe. "Roots need oxygen," she added.

Watering Shallowly Every Day

This causes the problems as described above.

Misting Your Plants

"This is probably the worst thing you can do because it can spread diseases," Carroll said. In the Southeast, she pointed out, even in a drought plants can have diseases that rely on water to transfer spores from one plant to another because there is so much humidity in the air. Misting plants can contribute to the problem of transferring diseases that can infect and kill plants.

View Article Sources
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  2. Tips On Irrigating Vegetables.” University of California Davis.

  3. Pierret, A., et al. “Understanding Deep Roots And Their Functions In Ecosystems: An Advocacy For More Unconventional Research.” Ann Bot, vol. 118, iss. 4, 2016, pp. 621-635., doi:10.1093/aob/mcw130

  4. Soil Testing.” PennState Extension.

  5. Stack, Lois B. “Soil And Plant Nutrition: A Gardener’s Perspective.” The University of Maine Cooperative Extension.

  6. Competency Area 5: Soil pH And Liming PO 39. Describe How Soil pH Affects The Availability Of Each Nutrient.” Cornell University.

  7. The Plant Doctor - Watering and Plant Disease.” Mississippi State University Extension.

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