In our recent hot afternoons, some of my plants are drooping and look like they need to be watered. How do I know if I am watering them enough because even after I water in the morning, they still look dehydrated in the afternoon. OD

Plants are kind of like people. Some people do not seem to be bothered by the heat while others of us don’t even like to go outside in the summer. Wilted leaves is a potential sign that you are not watering enough, but not necessarily. Let’s talk about how to tell if your plants are getting enough water.

Plants draw up water from their roots to transport nutrients throughout the plant. Plant leaves have small holes in them called stomata. These stomata open and close to allow water to evaporate from the leaves to help keep the plant cool. This process is called transpiration. During transpiration, the leaves absorb carbon dioxide which is necessary for photosynthesis.

When it’s really hot, some of the plants with larger leaves and consequently a higher quantity of stomata can have a hard time drawing up enough water to keep pace with the water being released from the leaves. Think about hydrangea or cucumber leaves. Other plants with smaller leaves and therefore not as many stomata, seem better equipped to draw up enough water to keep their leaves from wilting. But those bigger leaves can look pretty rough at the end of the day.

Only about 5% of the water that is drawn up into the plant remains as part of the plant. This water is important for maintain plant structure or plant rigidity. If you’ve seen a droopy plant that is all bent over when it’s dry but then perks back up after watering, this is what’s going on.

But, to complicate the issue, dehydration can also occur in plants that are being overwatered. Proper garden soil is about 25% water and 25% air. Air is essential in that it helps enable roots to absorb water. If the soil is over-watered, or saturated, the air is driven out which limits the ability of the plant to uptake water. Unfortunately, many a plant has met its demise as a result of being overwatered because the homeowner assumed wilted leaves meant it needed water. If this overwatering takes place over a longer period of time, the plant can develop a condition called root rot which ultimately kills the plant.

Here’s a couple of ways to tell if they have enough water or have possibly too much. If it’s in a pot on the porch, pick it up. If it feels heavier that it should, you have likely been overwatering, so let it dry out a bit and hopefully the plant will perk back up.

Also, if your plant looks droopy in the afternoon but then has recovered by morning, they are probably just losing water via transpiration faster than they can uptake more water. If the leaves are still droopy in the morning, you definitely need to increase the water you are providing to your plants.

If you want to be more exact in your determination, you can purchase a water moisture gauge. These are inexpensive and can be found at most any garden center. Good luck.

You can get answers to all your gardening questions by calling the Tulsa Master Gardeners Help Line at 918-746-3701, dropping by our Diagnostic Center at 4116 E. 15th Street, or by emailing us at mg@tulsamastergardeners.org. Photo: OSU Dept. of Ag. Communications