Overwatering really is a fine line with many species of plant. While we know plants need water, even cacti, the exact amount and frequency may be something of a mystery. Container plants with too much water may experience foliage die off, rotten roots and tubers, and promotion of some pests or mold issues. All of these stress the plant and compromise its health. Potted plants that are too wet may even simply rot off at the crown or base.
How to Avoid Overwatering of Container Plants
An obvious method to prevent overwatering in potted plants is with the use of a moisture meter. You also need to know your plant species and its watering needs. A broad guide for plants is to keep the top few inches (8 cm.) of soil moderately moist. When this area is dry, apply water deeply and then allow the soil to dry to the touch again, before adding more water. A low tech solution is to get your fingers grimy. Push a finger into the soil up to the second knuckle or test the bottom of the post through a drainage hole. Never let the bottom of the container rest in a pool of water unless it is an aquatic plant, and even then, drain and refill the saucer frequently to prevent fungus gnats and root rot.
What Plants Like it Wet and Which Like it Dry
Broadly speaking, even moisture is the best option for many container plants.
Low Moisture Plants
Cacti and succulents should have dry periods in the winter when active growth is not occurring but need moderate water during the growing season. Examples of other low moisture plants are:
Aloe Bromeliads Cast iron plant Ponytail palms Spider plants
Moderate Watering Needs
Tropical plants and understory specimens will need moderate water and high humidity. These include:
Philodendron Figs Dragon trees Bird of paradise
You can increase humidity with misting or by placing the pot on a saucer filled with pebbles and water.
High Moisture Plants
Extreme moisture needs are found in plants like:
African violet Lipstick plants Maidenhair ferns Dieffenbachia
Treating Overwatered Plants
There are some ways to save overwatered plants.
Changing the soil to a grittier mix with better drainage may help. Check the drainage holes at repotting and ensure they are open. Use containers that help evaporate excess moisture, such as terra cotta and unglazed containers. Remove the plant from its growing medium and rinse the roots to get off any fungal spores that may be forming. Then dust the roots with a fungicide and repot. Move your plant to a shady location, as plants in shade use less water and you can let it dry out a bit. After a few weeks, move it back to its preferred lighting level.
Sometimes you simply can’t save potted plants that are too wet. Container plants with too much water need to be treated as soon as possible, as the longer the situation continues, the less likely there is to be a full recovery.
