Overwatering could be just as problematic as underwatering, here are signs you can watch for on for each of these situations;
Leaves turn brown close to leaf margins and in between the veins or have dead patches in the middle. On lilies, generally the lower leaves are affected first, and when the soil is tested, it is found to be acidic. Leaf burn and leaf scorch occur when leaf cells overheat. Leaf scorch generally refers to browning and tissue death close to leaf margins and in between veins although leaf burn generally refers to dead patches that occur in the middle of the leaf. Both are caused by dehydration. When leaves dry out, the amount of water that evaporates is reduced and the leaves then overheat. Occasionally entire leaves or shoots are damaged. A number of problems might trigger leaf burn or leaf scorch. Leaf scorch may develop on lilies when they are being grown in acid soil having a pH lower than 6.5.
Underwatering plants will cause a plant to develop leaf burns and leaf scorch because the plants roots cannot find sufficient water. Plants growing in dry, salty, frozen soils or plants with limited rooting space may not get enough water either. A plants roots naturally reach out to absorb any water that is available to it in the surrounding area it is planted in. If no water or very little moisture is found the plant then becomes stressed and damage occurs. A plant can survive, if watered within a short period, but long term dehydration will cause too much damage and the plant will exhaust itself and die off.
Overwatering, and poorly drained soils can trigger leaf burn or leaf scorch as well. Roots need oxygen to function correctly. Wet soils low in oxygen trigger root death or root rot. The poorly drained soil or clay soil, keeps the roots from getting enough oxygen to the plant along with an accumulation of too much water which will cause the plant to drowned. In some cases, leaf scorch or burn occurs as the plant begins to die. The roots begin to die, they are not healthy enough to reach for any moisture, the plant then dehydrates because much less water is absorbed.
Wind and heat can also cause dehydration in plants. Hot, windy conditions trigger dehydration issues even when the soil is moist. Wind and heat cause the water to evaporate from the leaves very rapidly, so much so, that the moisture cannot be replaced.
Freeze damage will quickly cause plant leaves to turn dark brown or black. When the foliage freezes, the leaf cells then rupture or dry out and quickly die.
Other factors include diseased or damaged roots. If a plants roots are diseased or damaged then once again, the roots are not healthy enough to search for any surrounding moisture. The accumulation of salt within a plants leaf tissue can also cause scorch or burning. Once a plant is damaged it will not recover. Keep plants properly watered to eliminate further harm. If feasible, shade plants throughout really hot weather, and hose down foliage a couple of times a day. Protect shade-loving plants by providing adequate shade. Make certain the soil is moist when it freezes, and decrease chances of dehydration resulting from frozen soils by applying mulch close to the base of the plant. If lilies are growing in soil having a pH below 6.5, add ground dolomitic limestone to decrease its acidity and fertilize with a bulb slow-release plant food.
Overwatering harms all flowering plants, particularly those requiring well-drained soil. If the soil is continuously wet, the leaves will turn light green or yellow. Leaf edges might turn brown, and some of the leaves may die. In some cases the plant is stunted. Flowering is poor. If you pull the plant up out of the ground, the roots will be soft, mushy and rotted.
Overwatering is a serious and common issue that frequently results in the decay and death of plant roots. Roots need oxygen to function normally. Oxygen is contained in tiny air spaces or pores in the soil. When water is applied to the soil, the air is pushed out from the soil pores and replaced with water. If this water cannot drain correctly or is continuously reapplied, the soil pores remain filled with water. The roots cannot absorb the oxygen they require and they begin to decay. Since the roots continue to rot, they are much less able to supply the plant with nutrients or take up the water. Therefore, permit the soil to dry slightly in between waterings. It is also critical to enhance the soil drainage. Should you have heavy, poorly drained soil, use flowers which will grow in wet soil. Here is a list of flowers you can use, astilbe, bugbane, cardinal flower, ferns, Japanese and Siberian iris, Joe-Pye weed, marsh marigold, monkey flower, New England aster, and sweet white violet.