I am guilty of it myself. The first year growing Native milkweeds, we seriously over watered and lost about half of them. Now, I wait until the leaves are drooping no matter how dry the soil appears to be….the truth lies below the surface. I realized it is IMPOSSIBLE to simply look at the plant and determine if it needs water or not. The plant will let you know if you know to look for.
Wet and Wilting
1. It looks wilted, but the soil is wet. If your plant is green, well-watered and still struggling, you may have over watered. This is the easiest sign that your plant has had a little too much water. To prevent yourself from making this mistake again, only water your plants when the soil is dry to the touch. This little tip will keep you aware of plants that are in need of a good bath, and away from those who are full.
2. If the leaves turn brown and wilt, there is the possibility that you have been overwatering. At this point it may be difficult to tell whether a plant is wilting because of poor health, or improper water levels. Often, gardeners react quickly and throw on an extra pour or two of water in the hopes that the leaves will perk up. Before doing this, be sure to check your soil to see if it is wet. This doesn’t mean eyeing the top layer to see if it looks dry. Take and finger and place it into the soil at a point somewhere near the plant’s base. If the soil still feels dry, it may need water. Be sure to not let the fear of watering send you over the edge.
3. The third sign that your plant has been overwatered is edema. If a plant has absorbed more water than it needs, it can cause the plant’s cells to expand and stress. Often, these cells are filled to the point of rupturing. You can check for signs of burst cells by noticing any blisters or lesions on the plant. Eventually, these lesions will turn to dark or even white scar tissue. Another sign of edema is indentations on the top of leaves.
Yellow Falling Leaves
4. If you happen to have both yellowing leaves and new growth falling from your plant, there is a good chance you are overwatering. Try and remember if you have only watered your plant when the soil was dry.
5. Not only does the plant show signs of overwatering in its leaves and flowers, but the roots can also be an indication. When the soil is dense with water, it can limit the ability of the roots to breathe, they will then drown and begin to rot. Plant root rot is a fungal disease that will cause the roots to turn grey, brown or slimy and will eventually cause the plant to wilt. If a plant has root rot it is best to remove it from any garden bed so it cannot spread the disease.
Thank you Teleflora for the great info