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Garden Bed Watering Calculator – How Much To Water Your Plants Each Week

Enter the Length and Width of Your Garden Bed


  • Calculate the amount of time you need to water by using your preferred watering method (hose, watering can, etc.). Then, time yourself watering into a 5 gallon bucket. This will help you determine how long you’ll need to water your garden bed each week.
  • If you’re using drip irrigation, make sure you have enough emitters to dispense the amount of water needed each week. Drip emitters put out anywhere from 1/2-4 gallons of water/hour. Refer to your manual to determine the flow rate.
  • Adjust this number based on the rainfall each week. If you’ve gotten 1″ of rain, you don’t need to water at all.

This Garden Bed Watering Calculator is a helpful tool to determine the amount of water needed to irrigate your garden bed effectively. By entering the length and width of your garden bed in feet and inches, the calculator will tell you how much you need to water your garden each week. This is based on an average watering schedule of 1″ of water/week.

How it works:

  1. Input Length and Width: First, input the length and width of your garden bed in the provided fields. You can enter the dimensions in feet and inches for greater accuracy.
  2. Calculate Area: Click the “Calculate” button to find out the area of your garden bed that requires watering. The calculator will take into account the length and width you provided and calculate the area in square inches.
  3. Determine Water Volume: The calculated area represents the volume of water needed to water your garden bed with a depth of 1 inch. To convert this volume into the number of gallons required, the calculator automatically performs the conversion (1 cubic foot = 231 cubic inches).
  4. Watering Duration: To help you estimate how long it takes to water an area that requires a specific volume of water (e.g., X gallons), I recommend timing yourself while watering into a 5-gallon bucket. Observe how long it takes to fill the bucket to the desired level and use that time as a reference.

Note: The actual watering time may vary depending on your watering method and the water flow rate. However, this simple exercise with the bucket will give you a rough estimate of the time needed to water the garden bed with the calculated amount of water.

Calculating Rainfall

For even more efficient watering, consider incorporating a rain gauge into your gardening routine. A rain gauge is a simple tool that catches (and measures) the amount of rainfall your garden receives. This is a very inexpensive and helpful tool to have.

This is the one I use (Amazon link). I empty my rain gauge every Sunday so I know how much weekly water the garden has received.

If the rain gauge indicates that your garden has received 1″ or more of rain in a given week, you can skip watering altogether (nature has done the work for you!).

However, if the rain gauge shows less than 1″ of rainfall, you only need to supplement the total amount of watering based on the measured rainfall.

For example, if the rain gauge indicates 1/2″ of rainfall during the week, you should only water your garden with half the amount calculated by the Garden Bed Watering Calculator. This approach ensures that your plants receive the right amount of water without overwatering and helps conserve water resources during periods of rainfall.

By using the Garden Bed Watering Calculator in combination with a rain gauge, you’ll always know that your plants are getting the right amount of water. This proactive approach not only promotes healthier plant growth but also contributes to water conservation and sustainable gardening practices.

If you liked this garden bed watering calculator, you’ll also love my article & video showcasing my favorite watering tools to save time and effort in the garden.

Wrapping Up

This Garden Bed Watering Calculator aims to assist you in planning your garden watering efficiently. By knowing the required volume of water, you can better manage your gardening efforts and ensure your plants receive the proper amount of water for healthy growth.

Please note that this is based on an “average” amount of water suggested. If there is extreme temperatures of if you have plants that require more-than-average amounts of water, you may need to modify your calculations.

What Blooms with What?

Never know what to plant together? Find out with this FREE Plant Pairing Guide and become a pro at combining plants for the best garden design possible!

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