How to Know When It’s Time to Stop Watering for the Season
Yesterday I was talking with a gardener friend who lives in the southern US, and we were getting into a familiar debate: when is it time to stop watering? We both suffer from the same problem: It seems like a good time of year to turn off the hoses, but we don’t want to do it too early and harm (or kill) our plants.
By the end of the conversation, I realized that trusting my gut wasn’t going to help, and I decided that I needed to base my watering decisions on specific metrics—and you should too. If you suffer from the same kind of decision fatigue, here’s what to consider before you decide it’s time to turn off the tap.
Don’t worry about your lawn
When to stop watering your lawn is the easiest decision because you only need to ask yourself two questions: what is the nighttime temperature and is there a risk of frost? The latter is superior, so as soon as the temperature drops that much, turn off the sprinklers and bleed the air from the sprinkler system for the entire season.
If there is no threat of frost yet, then it’s a matter of night temperatures. Of course, the temperature at night is always lower than during the day, and that is what matters. When nighttime temperatures drop below 40 degrees, turn off the water.
However, to be clear, you should start cutting back on watering your lawn long before this happens. As the weather gets cooler, evaporation decreases, meaning your lawn requires less water. Consistent, deep root watering works best for all your plants, including your lawn, but water needs naturally decrease when it’s not as hot outside.
Your trees may need winter watering.
When it comes to trees, people tend to fall into two camps: those who like to water too much and those who don’t water enough. Most of us fall into the latter category. I am guilty of forgetting that the giant trees on my property cannot support themselves and require deep drip watering from time to time, especially in late summer. Once fall arrives, it’s time to start pruning as this will help the trees adapt to fall behavior, including shedding leaves.
However, there are some exceptions to this rule, and as parts of the US face drought, they are important to pay attention to. If your soil is very dry all winter, you should continue to water your trees. Only do this when the temperature is above 40 degrees (water can’t penetrate frozen ground and you don’t want to damage the plants), only do it if the ground needs it. To find out, dig a six-inch hole near the tree. If the soil is that dry, it needs to be watered. If it’s humid, leave the tree alone.
If you planted new shrubs or trees this year, or have trees with shallow root systems, continuing winter watering is especially important. Dehydration causes stress on trees, which can lead to damage.
Your vegetables still need water to sprout.
When you plant fall gardens, collect seeds, and put root vegetables and other hardier plants in the ground, they will need water, even in the fall. Seeds always need water to germinate, so if your vegetable seeds aren’t getting enough moisture from the environment, you’ll have to take care of it for them. However, if you are sprouting seeds, it may be preferable to switch to hand watering from above rather than using a drip line to ensure the seeds are completely saturated with water.
When it comes to small vegetables, their roots are not yet developed enough to access water deep below the soil surface, so shallow or drip watering is still important.
Stopping watering is part of winterizing your yard.
Most importantly, don’t risk damaging your irrigation system by waiting too long to water. Drain the water before there is a risk of freezing. (And while you’re there, remember the important role mulch plays in keeping the soil moist, which will help your plants.