How Much Water Does Corn Need?

Sweet corn needs a good deal of water to thrive and, because it puts down relatively deep roots, requires watering techniques that soak the soil well below the surface. Corn needs 1 ½ inches of water each week to produce an optimal crop. If corn is underwatered, it will conserve energy by “dropping” developing ears, and you will end up without a corn harvest.

How much water does corn need?

How Often Does Corn Need to be Watered?

Corn should be watered once per week for an extended period of time. This is preferable to daily watering sessions, which usually only soak the first few inches of soil. Shallow watering won’t reach the roots of your corn plants, which can range from 8 inches to 60 inches in depth, depending on the variety. Additionally, watering frequently to a shallow depth encourages weed invasion in your corn patch, as it feeds the shallow-rooted pest plants you don’t want.

By watering once weekly and making sure to soak the soil deeply, you provide the best irrigation for your corn.

Should You Water Corn Every Day?

No. Watering corn daily is both wasteful and ineffective. A short, daily watering period will only soak the first few inches of soil and may not reach the corn roots at all before it evaporates. On the contrary, if you water deeply on a daily basis, you will overwater your corn, which is just as harmful as not watering enough.

How Much Water Does Corn Use per Day?

Sweet corn growing in a field during the summer

Corn requires 1 ½ inches of water per week. Start thinking in weekly numbers with corn, as it prefers a good soak. Ever wonder why corn thrives in the stormy Midwest instead of the drizzly Pacific Northwest? This is partially because corn grows better when gets 1 ½ inches of rainfall in one big storm than over a week of light rainfall. When you water corn, you want to replicate that sort of stormy weather and deliver the water it needs for the week all at once.

How Long Should You Water Corn with a Soaker Hose?

1 ½ inches of water is a good metric for corn’s rainfall and overhead watering needs, but it doesn’t do the average gardener much good. Most of us use soaker hoses or drip lines. It’s time to start thinking in terms of watering in terms of depth. You’ll want to water corn to a depth of 30–36 inches. This gives us a good start. What comes next, is a soil watering test.

There is no hard and fast rule for watering times with soaker hoses because all gardens are different. A half-hour of soaking sandy soil will moisten the soil to a greater depth than the same time amount of time spent soaking clay soil. To determine how long you should water corn, follow these steps:

  • Lay out your soaker hose.
  • Water for five minutes, then turn off the water.
  • Wait two hours for the water to penetrate the soil.
  • Dig a small hole to see how far the water has penetrated.
  • Use this as a guide for watering depth. You’ll have to do a little math.
  • Example: If five minutes of watering moistens the soil to a depth of 5 inches, 30 minutes of watering will moisten the soil to a depth of 30 inches—perfect for corn.

Once you’ve dialed in how long it takes to soak your soil to the appropriate depth, you can use this to adjust watering throughout the year, depending on rainfall and other factors.

How Long Should You Water Corn with a Sprinkler?

Corn benefits from overhead watering, and instead of a drip hose, you may be inclined to use a sprinkler for your corn patch. This is a great idea! You just need to dial in the correct watering time for your corn.

A general rule for most sprinklers is that 1 hour of watering = 1 inch of water. Typically, watering your corn with a sprinkler once per week for 1 ½ hours will yield good results. To additionally dial in your corn watering needs, refer to precipitation rates for your model of sprinkler.

When Should You Water Corn?

Water corn in the morning, before peak sun and heat begin to evaporate the water intended to feed your plants. By watering early, when the day is cooler, more of the water will reach the roots of the corn plants. The best way to water your corn at the correct time is by using a wi-fi controlled irrigation timer, like this one. That way, you can easily adjust the time throughout the growing season, so you’re always watering at daybreak.

Easily Water Your Corn at the Correct Times
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Can You Water Corn Too Much?

Overwatering corn can be just as detrimental as underwatering. Overwatered plants will not produce ears, and will eventually wilt and die. Keep this in mind when watering. Subtract any recent rainfall from your watering schedule for the week. If you’ve already gotten over an inch of rain, you may not need to water at all.

When to Stop Irrigating Corn

If you see your corn leaves begin to yellow, wilt, or (in extreme cases) fall off, this is a sure sign of overwatering. If this occurs, reduce your watering times and watch for signs of improvement.

Mulch for Better Irrigation

On the flipside of overwatering, if your corn leaves begin to brown and dry, these are signs of water deprivation. This may be because water is evaporating before it reaches the roots. A good way to combat this is to add a 3–4-inch layer of mulch in your corn patch. This will help retain soil moisture and temperature, allowing better watering results with less waste.

Watering Sweet Corn

Sweet corn requires 1 ½ inches of water from rainfall or overhead watering per week. If you water via a soaker hose or a similar system, it’s all about watering until moisture reaches the correct depth. Corn has deep roots, so you need to water long enough that water reaches a depth of 30–36 inches. Because corn benefits from deep, soaking watering, it’s best to water once per week rather than daily, as this ensures adequate soil moisture.

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