The key to properly watering plants is all about paying attention. That's because there are no hard or fast rules. Determining whether a plant needs water or not is always a judgment call. It depends on the type of plant, the type of soil, the weather and exposure, the time of year, and many other variables.
In some cases, a sprinkler is the best option for watering a large area. However, only 40% of the water reaches the root zone. For more efficient watering, install a soaker hose early in the season, before the plants get big.
Every plant in your house or garden is probably unique in its water requirements. The only way you can accurately determine if you do or don't need to water, and how much water to apply, is by assessing the needs that particular plant. Fortunately this is easy to do — even for a teenager on a hot summer day. You just need to check the soil.
Get a feel for the weight of a well-watered hanging basket by lifting it.
If you're working in a nursery, the right way to do this is to lift each and every pot before you water. Over time, you get to know how heavy a pot should feel if all the soil inside the pot is consistently moist. If it is, you don't water. If it's not, you water slowly until all the soil in the pot is moist and water is running out the bottom. Then you lift the pot again to check that it feels right.
Watering is of no value if the water runs down the outside of the root ball, leaving the roots at the core of the plant dry. The point is to ensure that the soil at the core of the pot—where the plant's roots are located—is thoroughly moist. This is important to remember in the greenhouse when you're watering seedlings, in the house when you're watering houseplants, in the garden when you're watering your tomatoes, and in the landscape when you're watering shrubs and trees.
You can't use the "lift" test to evaluate whether or not the plants in your garden or landscape need water, but you can occasionally dig down 6 or 12 inches and see what's happening down there. A soil core sampler is perfect for this job, or you can just insert a sharp spade and then pull on it back to reveal a picture of what's going on down there. If the soil contains some moisture down to a depth of 6 or 12 inches, you're in good shape. If the soil in direct contact with the roots is bone dry, it's time water!
A few more tips and techniques for proper watering:
Originally Posted On: Gardeners.com By: Kathy LaLiberte