Water is one of plants’ most crucial needs. All plants need it, even cacti. Too much water, however, can be just as fatal to plants as the dearth of it.
How can you ensure you don’t overwater and subsequently kill your plants? By developing a good understanding of these concepts:
How plants use water
How overwatering plants affects them
The signs of overwatering
Gauging plants’ watering needs
The right way to water plants
How Do Plants Use Water?
95 percent of plants’ tissue is made up of water. Plants use water to perform photosynthesis, produce their own food.
They draw carbon dioxide from the surrounding air, hydrogen from the water their roots have absorbed. The water is then oxidized in the plant cells—it loses electrons to carbon dioxide. This process transforms carbon dioxide into glucose—the plants’ food.
This same process also converts water into the oxygen we breathe.
Plants also use water to keep themselves cool in hot climates. Water evaporates on the plants’ leaves, leaving the surface cooler. The roots supply the leaves with additional water to replace what’s evaporated.
Water also acts as a supply system within the plants’ bodies. Glucose and other nutrients are dissolved in water. They’re then transferred from areas of high concentration (the roots) to those of low concentration (flowers, foliage and stem). This transfer of glucose and nutrients is necessary for the plants’ reproduction and growth.
What Happens When You Over-Water Plants?
The impact of overwatering depends on how long you keep it up. The outcome is always undesirable. Here are some common effects of overwatering:
Excessive moisture at the base of the plants promotes the growth of fungi such as rhizoctonia. It also supports water mold or oomycetes such as pythium and phytophthora.
These microorganisms can also cause the following diseases:
Gummosis (foot rot)
Fruit brown rot
Damping off in seedlings
Reduced Supply of Oxygen to Roots
Plants’ roots draw oxygen from the air pockets in the surrounding soil. Presence of excess water in the soil causes loss of oxygen from the air pockets. As a result, the roots can no longer access oxygen.
Shortage of Water in the Plants’ Body
Overwatering plants damages the root hair—epidermal cell outgrowths responsible for absorbing water and nutrients. Prolonged waterlogging can kill the root hair, causing a shortage of water inside the plant.
Death of root hair can also destabilize the plant and create a shortage of food.
Common Signs of Overwatering
How to tell if a plant is overwatered? It’s simple—watch out for these signs:
The Soil Is Wet Half an Hour After Watering
If the soil has decent drainage (a must for virtually every plant) it should easily absorb the water applied to it within half an hour. If there’s standing water or wet soil even 30 minutes later, you’re definitely overwatering.
Brown and Wilting Leaves
Leaves turning brown and wilting can be due to poor health and improper watering. Touch the soil at the plant’s base. If it feels damp and you water regularly, there’s no need to supply more water.
If the soil’s still wet and it’s been some time since you supplied water, you’re likely overwatering.
Leaf Fall and Yellowing
If your plants have yellowed leaves and the new leaves have been falling, there’s a high chance you’re overwatering.
Check your plants for lesions or blisters. These are formed when the plant’s cells absorb excessive water and burst. These lesions will eventually darken or turn into white scar tissue.
The appearance of indentations on the surface of leaves is another sign that the plants are suffering from edema.
Decay in the roots is one of the surest signs of overwatering. The damage inflicted on the roots is often irreparable. It limits or stops the supply of moisture and soil based nutrients to the plants. This causes the plants to grow weak and eventually die out.
How to Fix an Overwatered Plant?
An overwatered plant that hasn’t started wilting can still be saved by switching to proper watering ways. Remove all dead and dying parts, including any rotting roots. Move it to a shaded spot, even if it’s a sun loving plant.
Applying a standard fungicide will help kill off the fungal infection.
How Much Water Do Your Plants Need?
An inch of water every week is usually a safe number. This applies to the majority of shrubs and flowering plants. If you spot signs of overwatering, it’s best to look up the water requirements for the particular species.
A plant’s watering needs depend on these factors:
Different plants have different water requirements. Most tropical plants relish moist conditions. You can let the soil get a bit dry on occasion and water them every 7-10 days.
Succulents such as cacti need to be watered less often. A deep watering every 2-3 weeks is enough.
A large plant typically has access to more soil than a smaller one. As such, it can make do with the moisture retained by the soil for longer durations than a smaller plant.
A plant growing in a 20 inch pot typically needs to be watered every 3-4 weeks. If planted in a 6 inch pot, the same plant will need to be watered every 1-2 weeks.
The Amount of Light It’s Getting
Plants that receive more light experience more water evaporation. They typically need to be watered more often than plants located in shaded spots.
Drainage Holes (For Potted Plants)
Plants growing in pots with drainage holes seldom face an issue with overwatering. The excess water simply drains out.
If you have plants growing in containers that lack drainage holes, you need to watch how much and how often you water them.
The soil’s moisture content is directly affected by temperature variations, rain and draft. One of the most reliable ways to know if your plants need watering is to gently probe the soil. If the surface is dry, water the plant.
The Right Way to Water Your Plants
It’s common for people to spray the leaves and flowers while watering the plants. It wipes off any dirt and makes them shine. Bad move. Plants absorb water much better through the soil than through foliage. Wetting the foliage can attract insect pests that relish moisture rich spaces. This puts your plants at a risk of infestations.
Never water your plants at night or late in the evening. The lack of light decreases the rate of evaporation and can leave the plants’ base and soil wet overnight. This promotes the risk of fungal infections.
Always apply water slowly, at the plants’ base. Fully saturate the soil. This will prevent wastage of water. It will also ensure the optimal utilization of water and that you don’t have to water too often.
Heeding the information shared in this article will help you avoid overwatering plants. Still unsure or can’t find the time to support your plants’ water requirements? We’d recommend you hire a plant watering service, ensure your plants stay well-hydrated and beautiful.