"It rained for three days. How do I know when I need to water again?"
Watering questions are some of the most common gardening questions I get.
It's hard to know exactly how much rain came down when you're staring at it through your kitchen window. Three days of light rain on and off can add up to a few inches of rain and a super heavy one hour rainstorm can sometimes be barely a quarter of an inch.
So how to know?
What you need is a rain gauge!
Most vegetable gardens need 1"-2" of water a week (unless it's super hot and your plants are loaded with tomatoes). The three days of steady rain we had this past weekend filled my rain gauge up to 4"! That means I most likely won't have to water again until next week! Make sure to hang your rain gauge in a place with no overhanging trees or roofs and in a place that's easy to access so you can empty it often.
Of course I'll still check my soil moisture level by getting my fingers in there. Sticking a finger or two a few inches into your garden soil is the best way to know if your garden needs watering! The surface can dry out fairly quickly, but as long as there's water a few inches down your plant roots can drink.
My method of watering my garden is with a hose and a "watering wand" attachment. Use the "rain" setting to water your plants and get it in there near the surface of the soil when watering. And then stand there and wait! You want to water deeply not just wet the surface of the soil. This can take easily 3-4 minutes for a 10 square foot area depending on your hose, wand and water pressure. I like to listen to podcasts when I water to make sure I'm not rushing through it and my soil gets watered well. You can use the finger method mentioned above to check your soil to make sure enough water got down where it needs to be.
Don't water too often! If you water your garden every day your plant roots will get lazy. Instead of growing deep they will spread out horizontally to drink up the small amount of water they are getting daily. The goal is always to train your plants to have deep root systems so they can access water that is deeper in the ground. This leads to healthier plants that can survive the heat of the summer better and produce more vegetables. The way to do this is to water deeply and less often and pay attention to the rain!
Now this does NOT apply to plants in planters. Since there is a limited amount of soil only a limited amount of water will be in there. The best way to check if your planters need water is to put your fingers in the soil a few inches down and feel for moisture.
Also, very young plants or newly planted seeds need watering more often as their roots can't reach very far down yet. Carrot seeds for example, need watering every day for up to three weeks until they sprout and newly planted seedlings may need to be watered every other day or so until they are established.
This is the rain gauge I use and recommend* . It is easy to read. Just remember to empty it so you can keep track of how much rain has fallen. And if it overflows you DEFINITELY don't need to water this week :-)
If you're looking for a watering wand you can look at your local Home Depot or Lowes or check out my Amazon Shop . I have a few heavy duty watering wands in the "Garden Tools" list. The heavy duty ones usually have a better flow rate than the regular ones which can save you a lot of time watering. They also tend to hold up better over time.