The Most Common Mistake People Make When Growing Herbs Indoors

Indoor herb gardens have gained popularity among American homes because they provide an efficient means of growing cooking ingredients without the need to have an outdoor garden. Herbs like basil, parsley, mint, and thyme can thrive on the kitchen window or under a simple growing light. But new gardeners face the same problem. Their plants seem to be thriving for a while, then suddenly wilt, turn yellow, or stop growing altogether.

According to horticulture experts, the main reason for the problem is not the type of soil or the failure to fertilize the plants. The main problem is the incorrect watering of the plants. While the plants need to be watered regularly, too much water is bad for the herbs.

Why Watering Mistakes Are So Common

Many people believe that watering plants often is a good way to care for them. This is not true, though, because herbs are used to living in a soil environment where the soil dries out between rainfall events. This will cause the soil to lack oxygen, which will allow bad fungi to grow.

The University of Maryland Extension states that overwatering is one of the most common problems associated with indoor container gardening. According to their plant care information, "indoor potted plants that are waterlogged for long periods of time create the perfect environment for root rot, a disease that kills the roots of the plants, preventing them from drinking water and nutrients."

Understanding Root Health

Both moisture and oxygen are important for the roots to stay healthy. When the soil becomes too wet, the spaces between the soil particles are no longer filled with oxygen but with water. This interferes with the proper functioning of the root system.

Experts from the Cornell University College of Agriculture and Life Sciences state that roots need oxygen to respire.

Respiration is the mechanism through which the plant is able to metabolize the sugar it has stored into a usable form of energy. When the level of oxygen in the soil becomes too low, the roots become weakened, which makes them more susceptible to infection.

A horticulture guide published through Cornell Cooperative Extension states that too much water in the soil can lead to a condition conducive to the growth of fungi such as Pythium and Phytophthora, which cause the roots to decay, a condition referred to as root rot.

Indoor environments may take longer to dry the soil compared to the garden. The circulation of air within the house is usually low, and the use of containers may hinder the draining of the water compared to the garden.

According to the Purdue University Extension, the loss of water by indoor plants is gradual since the amount of wind and sun is reduced. The soil may take longer, usually up to three days, to dry after watering.

Signs That Your Herbs Are Overwatered

Another symptom is the infestation of fungus gnats, which are small insects that live in moist potting soil. This usually occurs when containers are wet for a long time.

According to the National Gardening Association, which offers guidelines on indoor gardening, rosemary, thyme, and oregano are more susceptible to overwatering because they are originally from Mediterranean countries, where drainage is fast.

How to Water Herbs Correctly

Experts suggest checking the soil's moisture level before watering instead of following a routine. To do this, you can insert a finger into the soil up to an inch. If the soil's surface is dry at this depth, it is likely the plant needs watering.

Another aspect to consider is the kind of potting mix you are using.

A light-weight potting soil mix is best suited for pot cultivation because it does not compact the soil. Such potting mixes have air-permeable additions like perlite or vermiculite.

Light levels are also a factor in the watering of herbs. Herbs growing in direct sunlight or artificial light have a high water requirement because the rate of photosynthesis increases the metabolic rate of the plant.

The Penn State Extension recommends keeping the herbs near the south-facing windows of the room whenever possible.

It does not take any special equipment or expertise in gardening to grow herbs indoors. In most instances, the distinction between a thriving indoor herb garden and a failing one comes down to understanding how the plant reacts to water.