How much water??

How much water do your plants need? This is a really common question among gardeners and one that I’ve been trying to find a good answer to for.

General rule of thumb is an inch of water per week for fruit bearing trees and shrubs when they’re producing fruit. Vegetables can be a little trickier since they can quickly be impacted by not having enough water, especially when the temperatures start to go up. Or too much water which can often be the case in Florida during the summer rainy season

Vegetables like cucumbers and tomatoes require a fair amount of irrigation. Without proper watering they may grow, but the fruit quality will be lacking, undersized and flavorless. The key is really making sure that the soil doesn’t ever fully dry out. For that a soil moisture tester can come in handy.

I’ve been fine tuning my micro-irrigation set up over the last several weeks. Here are are few pictures of my cukes and tomatoes. Both have really taken off and that is in large part due to the regular watering they get.

Cucumber plant


Tomato plants











No matter how you’re watering, whether by hand or with micro irrigation, here are some numbers that will help you calculate how much water you’ll need.

  • 1 and a half to 2 square feet of garden per gallon of water equals about 1 inch
  • 1 inch of rain fall equals 4.7 gallons per square yard

I’m not the best with math, but this is pretty straightforward. If you know the dimensions of your garden it should be relatively easy to figure out how much water to apply.

One square foot is 144 square inches. If you cover that with an inch of water you’ll need 144 cubic inches. One gallon is 231 cubic inches. Dividing 231 by 144 = 0.62 gallons. So a plant growing in about 1 square foot of soil needs a bit more than half a gallon of water a week to equal 1 inch. A 4 ft x 8 ft bed = 32 sq. ft. so at 0.62 gal/sq.ft. you’d want to give it about 20 gallons of water a week.

Locally, we haven’t had a good rain in a couple of weeks, so it’s important to keep up with your thirsty plants. Happy watering!!


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