If you have a garden, you were probably struggling with the eternal question: how much water does my plants really need?
That’s why I created this plant watering calculator. Remove any speculation from knowing how much water your plants. Simply enter details about the plant and garden condition and the tool outputs the optimal amount of water you need each week.
Plant watering calculator
result
Water required: 0 Gallons per week*
*For newly planted trees, apply this amount of water each week for the first 2-3 weeks, 3 to 12 weeks every other day, then every week until the tree is established (usually takes about 1/2 years for every inch of the trunk caliper).
Note that the above results are only guidelines and adjustments may be required due to other factors, such as time of year, drought, excessive rainfall, plant age, mulch use, or type of gardening (for example, growing in containers and on the ground).
How to use this tool
You’ve probably heard the typical advice of giving plants “1 inch of water a week,” but that’s just as clear as mud. (I’m breaking down math in another post and about what an inch of water in the garden really means.)
It’s even more confusing when you consider all the different types of plants, the composition of the soil, and even the weather in a particular area.
This calculator takes all of that into consideration to provide a simple starting point for watering, measured in gallons.
Select the plant type: Select the plant type to water. Options include vegetables, flowers, shrubs and newly planted trees. Select the type of soil. Choose the type of soil in your garden. Options include Sandy, Loamy, and Clay. Select a Climate: Choose the typical climate for your area. Options include dry, medium and wet. Enter Plant Size: Enter the plant size in square feet. For multiple plants, calculate the total area occupying in square feet. For wood, enter the trunk caliper (diameter) size in inches. Calculate water volume: Click this button to return the recommended amount of water and give the plant each week.
What will you do with your outcome
So you have the actual number of work. How do you deliver this amount of water to your plants in the most effective way?
Generally, most plants do their best by watering deeper (but less frequently) than weekly. Many people (including me when I first started gardening) simply give the plants a small water that wets the top layer of the soil.
Watering this way will quickly evaporate the moisture, leaving the roots close to the surface and more likely to dry out (and therefore need to be watered more frequently). It is also susceptible to temperature fluctuations, which can lead to heat stress and frost rise.
Watering deeply, that is, slowly and thoroughly to saturate the soil, will encourage the roots to move deeper. And only when the first few inches of soil feels dry, you water it again.
This may mean watering 2-3 times a week, depending on the season and current weather conditions. So, get the number of gallons recommended by the calculator, divide by 2 or 3 to get the exact amount of water you need for each watering session (either by hand with a garden hose or watering can, use a sprinkler system, or automate with drip irrigation).
Note that due to the shallow roots, seedlings and new transplants require more frequent watering, but there is less water each time.
Despite their name, drought-resistant plants require regular watering until the roots are well established, at which point they can reduce the amount of water you give.
In winter, your garden still needs water. It is reduced according to the climate.
The principles behind the calculator
My plant watering calculator is based on established horticulture and agricultural principles to provide accurate water requirements for different types of plants under different conditions.
The following important factors are reflected in the calculations:
Plant type
Different plants have different water needs. For example, vegetables usually require more water than flowers. The calculator uses the following baseline amounts for each plant type:
Vegetables: 0.6 gallons of water per square foot per week: 0.5 gallons of water per week shrub per 4 gallons: 0.3 gallons of freshly planted trees: 1.5 gallons per week (after the first 3 months)
Soil type
The soil texture greatly affects the amount of drainage or moisture retention in your garden, and determines how much water your plants should be given.
Sandy soil drains faster and requires more water and more frequent watering. Loamy soil has a good balance between drainage and moisture retention. Clay soils are dense and retain moisture for a long time, so they are low in water and require frequent watering.
climate
Local weather conditions (including average rainfall and humidity) affect the plant’s evaporation rate and overall water needs.
Dry climates have a higher evaporation rate and require more water. Moderate climates have average conditions. Moist climates evaporate less and require less water.
