I must be crazy hauling out my hose in the middle of winter and watering the garden! In fairness, only my container plants are undercover; I don’t water the entire garden. Mother Nature is keeping it happy with rain and snow. Plants in containers on the porch or patio and protected undercover in an unheated greenhouse or garage do need attention.
Even in the winter, plants need water to survive. Cold, just like heat, will cause soil to dry out and erode. By keeping the soil moist, it stays active, and the plants survive.
Fun Fact: Water is above freezing, giving off heat, which can help protect the plant roots in extreme cold.
How do you know if a plant needs winter watering?
Overwatering can cause the container to break due to ice expansion in the soil. Too much water will cause root rot, and the plant will die. I use a water meter to gauge the moisture in the soil before hauling out the hose.
Alternatively, you can feel the top of the pot to see if the soil is damp or gauge water needs by the color of the soil. Dark soil indicates moisture in the pot, while sandier-colored soil suggests the pot is dry and time to water.
Watering Tips
When it comes time to water, I carefully pick the time of day. The best time is around noon when temperatures are above freezing on a sunny day. This gives the plants time to absorb the water at the highest heat of the day instead of at night when there’s a greater potential for freezing.
I also make sure to check the containers that I’ve wrapped for the winter. Just poke a tiny hole in the burlap or other material you’ve used, insert a water meter, or feel the soil to see if it’s wet.
When watering, I pour into the soil or a bottom tray for three to five seconds. Underwatering in winter is much better than overwatering, especially if you are watering from the bottom onto a tray.
If the plant isn’t thirsty, it won’t suck the water up, and this could lead to root rot or freezing that clogs the drain holes of the container. If the water is still in the tray after a day or so, empty it.
How often should you water containers undercover in winter? That depends on your climate, but as a general rule, only three or four times during the season is enough to keep the plants moist and alive. And that’s all that matters.