When to Water Your Vegetable Garden | Watering Chart

Watering Chart for Vegetables

Garden Hose

How much water do you really need? When is the best time to water your vegetable? See our tips on watering your garden—plus, our Watering Guide listing critical times on when to water your crops and how much water they need.

According to some experts, less is often more when it comes to watering your vegetable crops. In areas without drought, a common mistake new gardeners make is watering too much!

Historically, gardeners have been advised to make sure that vegetables are getting an inch of water a week. The old rule of thumb of watering 1 inch per week originated from an understanding that, on average, it takes about 1 inch of precipitation at one time to deliver enough moisture to the deep root zone. In fact, this is not the case. For example, clay-based soils hold more water than sandier soils, so an inch of water a week could result in overwatering.

More important, there are methods and practices that can result in using less water but achieving better results with your plants.

Start With Good Soil

The best garden results start with good soil. Browse our Web site for advice on soil types, soil testing, and the basics on amending your soil with NPK fertiliers and organic amendments.

Cultivate Your Crops

Before the advent of hoses, water pumps, and trickle irrigation, farmers and gardeners practiced regular cultivation. Frequent cultivation prevents the wicking up process that draws water from the lower levels to the surface of the soil, where it is lost to evaporation. By aerating the upper layer of soil, cultivation also greatly improves the capture and retention of rainfall. Plus, it disrupts the germination and growth of weeds that would compete with crops for water.

Cultivate your garden early and often. A rototiller or push cultivator is good for large beds, but hand tools work fine in small plots. Alternate between fluffing up only the first inch or two of soil and tilling down 5 or 6 inches—always being careful not to disturb crop roots.

Timing is important: Many gardeners stop cultivating their gardens in midsummer once crops are established enough to out-compete weeds. But midsummer is the hottest time of year, when soil and plants are most vulnerable to moisture losses through evaporation and transpiration. Also, midsummer rains often come fast and furious, in the form of violent cloudbursts that dump a lot of rain in a short time. Frequent cultivation prepares your plots for dramatic percolation, allowing you to capture as much of that rainfall as possible, rather than have it run off or just puddle on the ground.

Traditionally, farmers and gardeners have cultivated their crops 3 days after a good, soaking rainfall to prepare the soil for the next rainstorm. And they often cultivate again just before a predicted thunderstorm.

After a rainfall, stay off (do not step into) freshly cultivated soil for 3 days. This will prevent soil compaction, allowing the rainwater to percolate down to the lower root zone. You want plants to root deeply so that they do not become dependent on surface watering.

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Make Mulch Matter

Mulching is perhaps the #1 water-conserving technique for areas that receive less than 40 inches of rainfall annually. Organic mulches reduce evaporative moisture losses from the soil surface, and because the soil stays cooler, they also reduce transpiration water losses.

Mulching goes hand in hand with cultivation. After starting with bare ground, cultivate your crops in the early part of the season to keep the soil well oxygenated, until plants become established. If you are growing vining crops—cucumbers, melons, and squashes—apply mulch as soon as the plants begin to set runners. With fruiting crops such as tomatoes and peppers, wait until the blossoms drop and the plants begin to set their main crop.

See our Mulching Guide for more information.

Lose Your Guilt About Wilt

Temporary wilting during the heat of midday does not mean that it’s time to water. Some plants go through an obvious midday slump, which is an indication of the plant’s natural adaptation to its environment. Visit your garden again in the early evening and see if the wilted plants have regained some turgidity. If they have come back—that is, if they look perkier—do not water.

Don’t baby your crops: Plants are incredibly adaptable. They have the ability to draw water from deep in the soil. Periodically, take a trowel and dig down several inches into the zone where the roots are most active. If the soil there is still moist, there would be no benefit from watering.

How and When to Water

What you want in a healthy plant is deep root penetration, and the only way that you’re going to get deep roots is if there is water down deep.

Start at the very beginning: Saturate each plant hole when you transplant seedlings. When you do water, make sure that you get the soil saturated enough that the moisture percolates several inches down.

Believe it or not, sometimes the best time to water is during or immediately after a rainfall, especially if the rain shower amounts only to a half-inch or so of water. The reason for this is that you want to add sufficient water at the same time to ensure penetration down to 5 or 6 inches. If you wait another day or two to water, you will be adding only surface water, which evaporates rapidly. With only frequent, light watering (or rain showers), you never build up a reserve of water in the soil.

So, cultivate, mulch, and water in the rain. And learn from nature: Spend more time observing your garden and less time watering. 

See our video with 10 smart watering tips for a healthier garden.

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Watering Guide: Critical Times to Water and Amount of Water Needed

To address the big watering question, below is a chart that tells you critical times to water each vegetable crop as well as the number of gallons of water needed.

Of course, these guidelines assume that you have rich, well-balanced soil. Increase frequency during hot, dry periods.

 Needs a lot of water during dry spells.  Needs water at critical stages of development.  Does not need frequent watering.
Vegetable Critical time(s) to water for a 5-foot row Number of gallons of water needed
Beans When flowers form and during pod-forming and picking 2 per week depending on rainfall
Beets Before soil gets bone-dry 1 at early stage; 2 every 2 weeks
Broccoli Don’t let soil dry out for 4 weeks after transplanting. 1 to 1 ½ per week
Brussels sprouts Don’t let soil dry out for 4 weeks after transplanting. 1 to 1 ½ per week
Cabbage Water frequently in dry weather for best crop 2 per week
Carrots Before soil gets bone-dry 1 at early stage; 2 every 2 weeks as roots mature
Cauliflower Water frequently for best crop. 2 per week
Celery Water frequently for best crop. 2 per week
Corn When tassels form and when cobs swell 2 at important stages (left)
Cucumbers Water frequently for best crop. 1 per week
Lettuce/Spinach Water frequently for best crop. 2 per week
Onions In dry weather, water in early stage to get plants going. ½ to 1 per week if soil is very dry
Parsnips Before soil gets bone-dry 1 per week in early stages
Peas When flowers form and during pod-forming and picking 2 per week
Potatoes When the size of marbles 2 per week
Squash Water frequently for best crop. 1 per week
Tomatoes For 3 to 4 weeks after transplanting and when flowers and fruit form 1 gallon twice a week or more

How to Measure Your Water

If you set up a rain gauge or bucket in the garden, you can measure how much rain or irrigation water your garden is getting and time how long it takes your watering system— or a good steady rain—to drop an inch of water. Use a clean, empty tuna or vegetable can as a gauge. Measure its contents by putting a ruler into the water it collects. 

 

For more on watering the garden, especially in drought, read our article on “The Water-Wise Garden.”

Reader Comments

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VEGETABLE GARDENING

I LIVE IN YUCCA VALLEY, CA. IT'S 98 DEGREES AND 70 OR SO AT NIGHT. THE WIND BLOWS 5 MILES PER HOUR FROM 10 A.M. TIL 4PM EVERYDAY. I WATER ONCE A DAY BUT YEILD IS NOT WHAT I'D LIKE. THE GARDEN IS SUN SCREENED. HELP??

yield troubles

To conserve moisture, make sure you provide a good layer of mulch around your plants. To prevent evaporation from wind, you might set up a windbreak. It could be, too, that it is not your watering but the heat itself that is affecting yield, as some plants slow down production in high heat. Sun screen is good to provide partial shade, especially during the times of strongest daylight. Perhaps next year, also look for heat-tolerant vegetable varieties. Your county’s Cooperative Extension might have further tips. For contact information, see: http://www.almanac.com/content/cooperative-extension-services  (At the California link, select “San Bernardino County”) Hope this helps!

Poor yields

I know this is a year late but also check your soil. I had to add better soil to one part of my garden .

Potted plants

When is water necessary for plants grown exclusively in pots? I live in apt and have several wild flowers that come back each year and also grow vegetables. Broccoli, squash, tomatoes and others. Thanks!

You can use the chart above,

You can use the chart above, even if you are gardening in containers.

I live in Fort

I live in Fort Lauderdale,Florida.Some days are really hot.My garden is,all about vegetable containers...do I water them twice a day or once a day? Because my tomatoes `leaves become yellow...do I need to water them until see water tp come out from the botton containers holes ? Thanks

It is easy to overwater when

It is easy to overwater when plants look stressed in the heat. Stick your finger in the soil to see how dry the soil actually is before grabbing the hose. Water when it is dry 2-3 inches down from the top. Yellow leaves on tomatoes are often a sign of overwatering or they could signal a soil deficiency.

tomato leaves turnig yellow

my experience tells me clearly having been a been a commercial organic grower of medicinal herbs which I specialize in and vegetable that a deficiency of nitrogen in the soil is usually the problem. If your soil has a high acidity level this disallowes the plant from drawing the nutrients it needs to grow naturally. Regards neil price a commercial organic grower of 20 odd years experience.

What is the best way to water

What is the best way to water Watermelon Plants & what type of feed should be given.I start mine from seed, but they don't seem to be doing well this year. Is there something I'm doing wrong

We planted more vegetables

We planted more vegetables this year. We have yellow pear tomatoes, Fourth of July tomatoes, lemon cucumbers, and a couple pepper plants. On this chart, the tomatoes and cucumbers are mentioned but not the peppers. Last year was our first attempt growing anything and it was cherry tomatoes. We had an over abundance! We just aren't sure how to care for this new garden. We have sandy, clay soil that gets FULL sun all day. Any advice on watering and care?

We'd advise having the soil

We'd advise having the soil checked again -- it won’t be both sandy AND clay. If it seems to be somewhere in between, it’s an ideal loamy soil, and full sun is good but in a very hot climate this may mean extra watering is required. The video has tips on watering -- tomatoes and peppers like plenty of water and it’s important not to let tomatoes in particular dry out too much before watering again, as the fruits can crack and it may also contribute to blossom end rot. Mulching is also important to help retain soil moisture.

I have a question about using

I have a question about using painted sticks as garden markers will the paint affect my garden

Hi, Momma: It sort of depends

Hi, Momma: It sort of depends on the paint type (should be outdoor), but it is hard for us to imagine much harm arising from this. Good luck!

Great tips! Sometimes when

Great tips!

Sometimes when you suffer from high water bills or dead grass, you might have a problem with your irrigation system. In the long run, installing the right irrigation system saves water and provides a healthy & beautiful landscape for your property :)

Is the "number of gallons per

Is the "number of gallons per week" column meant to list how many gallons per individual plant, or a 5-foot row like the "critical time..." column?

The number of gallons per

The number of gallons per week is for the 5-foot row, not the individual plants.

I am working on an article

I am working on an article that correlates plant water consumption and the one-inch of water per week rule of thumb. Runoff, percolation, transpiration, evaporation; plant spacing and that elusive well drained water retaining soil; it should all come together from the “Water Needed” column.

Used to garden big time in

Used to garden big time in Bakersfield, CA: SUN & FREE WATER!! Now I'm in Sacramento with a water meter and I'm at a loss as to how to afford the water. . .

Your best bet is to build a

Your best bet is to build a "reservoir" that will capture rain water. Build it up high, with a valve at the bottom, so that gravity can feed it for you. Otherwise you will need a pump to get it out. You can find out more about doing this online. You can really use this to save HUGE on water bills. Thank God I have a pump and a well where I live. Still pay for electricity though!

Robert Leavitt
leaveittoleavitt
Gardening on a shoestring budget

reservior

Robert, it rarely rains in CA during the summer.

Just dig your own water well.

Just dig your own water well. There are many websites with instructions on how to do thiis on your own, and on a low budget, I adapted the methods I saw to work at high elevation in North Texas. About $50 in PVC and another $30 added to the water bill I was able to use water pressure to dig a hole in the ground to the water table. Of course I had many problems, the you may not encounter as your a few hundred feet closer to sea level, I had to find the saturation zone, provided by lakes and rivers, you will find the saturation zone more shallow as the ocean is closer and helping bring the saturation level up.

Hi read your comments on

Hi read your comments on drilling our own well.Please could you provide details.I live in Cranbrook B.C. My understanding is this used to be an ancient lake.There are creeks that run under ground through the city in areas.and If this is of any help to you to help me I would appreciate it
Thankyou in advance
sincerely
Paul Valentine.

I live in Phoenix,Arizona and

I live in Phoenix,Arizona and recently planted a tomato, cucumber and a squash plant that i bought from a nursery into a Topsey Turvey. The plants seemed to be fine and were staying green. It's late May and I have noticed that the cucumber leaves are drying out. I water my plants every other day. I noticed last night that my squash leaves are starting to yellow a bit and drying as well!

Many readers enjoy the

Many readers enjoy the benefits that come with a Topsy Turvey but it also comes with some other challenges; namely, the hangers heat up and dry out quickly, causing the soil to be become hard and compacted. It's important to monitor closely so that they soil doesn't dry out. You also might want to beef up the soil with peat moss and humus and give them a fertilizer spike.

yellowing leaves, tend to be

yellowing leaves, tend to be signs of nitrogen deficiency. Remember to feed your plants the nutrients they require.

Michael we live in Zone 9,

Michael we live in Zone 9, when we reach the months of 90s to 100's ---like you we water multiple times a day--like a patient in the hospital, when every the drip bags are dry.

If my tomato container plants

If my tomato container plants are turning yellow ... Too much water?

Good guess. Usually yellowing

Good guess. Usually yellowing leaves are due to overwatering, especially in containers, and especially if your soil has poor drainage. Also, watering leaches nutrients so make sure you keep feeding a container plant.

We live in North Western

We live in North Western Montana and have a greenhouse as well as an outdoor garden. So, in the greenhouse all our garden is in pots, how much water is needed and how often? It seems we are watering daily!

I water my garden in pots

I water my garden in pots twice a day, and on really hot days, 3 times per day.. doesnt take long for the pots to go dry.