Distinguishing Overwatering from Underwatering: A Comprehensive Guide for Houseplants

When it comes to maintaining houseplants, one of the most common challenges for plant enthusiasts is determining whether they have overwatered or underwatered their plants. In this article, we will explore the signs of both, explain why these terms are misleading, and provide practical tips for monitoring and managing soil moisture.

Understanding the Basics

Overwatering and underwatering can be confusing concepts. Overwatering refers to watering a plant too frequently, which can lead to waterlogged soil and poor root health. Conversely, underwatering occurs when a plant does not receive enough water, causing the soil to dry out too quickly. Both conditions can result in similar visual symptoms, making it crucial to understand the underlying causes.

The First Signs of Overwatering and Underwatering

One of the earliest signs of overwatering is brown leaf tips. This occurs when the roots are unable to absorb sufficient oxygen due to overmoisture. The

Conversely, the first sign of underwatering is often wilting leaves. You may notice the leaves starting to wilt, with soft edges, curling, drooping, and sometimes turning yellow. As the condition worsens, the symptoms can become similar, with leaves and stems becoming yellow and drooping, and eventually browning and falling off.

How to Determine What’s Happening

Testing soil moisture is the key to understanding whether your plant needs more or less water. There are several methods to do this:

Probes: These can be electronic or manual. Electronic moisture meters are widely available at plant stores, while manual probes like a narrow wooden device, bamboo skewer, or chopstick can be used. Finger Feel: You can also use your finger to check the moisture level, but be aware that the top inch or two of the soil might not accurately reflect the moisture down where the roots are. Weight of the Pot: As you become familiar with your plants, lifting the pot can give you a good indication of whether more water is needed.

The ideal moisture level varies by plant species. For example, cacti and succulents prefer very dry soil, while ferns and some tropical plants require consistently moist soil. It's important to know the specific needs of the plants you have.

Target Moisture Level (TML)

The Target Moisture Level (TML) is the point at which your plant needs water. This level is specific to the plant species and can vary based on environmental factors such as size, age, light conditions, and pot size. As a general guideline:

Overwatering occurs when you water the plant too frequently, before the soil is sufficiently dry. Underwatering occurs when the soil remains dry for too long, either due to infrequent watering or insufficient water volume.

How to Test Soil Moisture

Here are the steps to test soil moisture using probes:

Push the probe all the way to the bottom of the pot. For electronic meters, ensure they go in and out again with little pause. For manual probes, leave them in the soil for a few seconds and then feel them as soon as you bring them up. Use your fingers to check moisture, but be aware that the moisture at the top inch or two might not represent the moisture at the roots. Electronic meters can malfunction, so always run them between your fingers to ensure proper readings.

For more detailed information on watering houseplants, you can refer to my answer on the recommended frequency of watering.