Blog – Temporary Climate Solutions

How Humidity Affects the Growth of Plants

Everything in an environment affects how a plant grows, thrives and reproduces. When growing plants indoors, climate control is essential to maximize the photosynthetic process. By maintaining optimal relative humidity levels in a greenhouse and other growing environments, you ensure optimal plant transpiration.

The Effects of Humidity on Plants

The relative humidity is the amount of water vapor in the air relative to the maximum amount of water vapor that the air can hold at a certain temperature. If the relative humidity level is 75 percent at 80° F, this means that every kilogram of the air in the respective space contains 75 percent of the maximum amount of water that it can hold for the given temperature.

Relative humidity levels affect when and how plants open the stomata on the undersides of their leaves. Plants use stomata to transpire, or “breathe.” When the weather is warm, a plant may close its stomata to reduce water losses. The stomata also act as a cooling mechanism. When ambient conditions are too warm for a plant and it closes its stomata for too long to conserve water, it has no way to move carbon dioxide and oxygen molecules, slowly causing the plant to suffocate on water vapor and its own transpired gases.

As plants transpire, the humidity around saturates leaves with water vapor. When relative humidity levels are too high or there is a lack of air circulation, a plant cannot make water evaporate (part of the transpiration process) or draw nutrients from the soil. When this occurs for a prolonged period, a plant eventually rots. When surrounded by warm temperatures in low relative humidity levels, transpiration rates in a plant increase, increasing the need for a grower to fertilize it.

The Importance of Climate Control for Plant Growth

As seedlings grow or when a grower propagates plants from leaf or stem cuttings, the young or collected plants automatically close their stomata as a protective measure to prevent water losses. To support cuttings and young plants, growers often use plastic tents or propagation chambers that increase relative humidity levels surrounding the leaves and ensure proper air circulation.

In addition to water and air, plants use light energy for the transpiration process, as it causes liquid water to turn to vapor (evaporation). Greenhouses often maintain relative humidity levels below threshold values during the day and night by controlling the water content in the air to maintain a minimum transpiration rate in plants.

Climate control for plant growth is an essential consideration in regards to pest and disease management. When conditions are too humid, it may promote the growth of mold and bacteria that cause plants to die and crops to fail, as well as conditions like root or crown rot. Humid conditions also invite the presence of pests, such as fungus gnats, whose larva feed on plant roots and thrive in moist soil.

Managing the growth and development of plants involves manipulating a growing environment so light, temperature, and relative humidity levels promote photosynthesis, high yields, and generative growth. Optimal transpiration rates vary by plant type, age, and season, making climate control for plant growth necessary throughout the year. Polygon offers custom-made temporary climate control solutions that create the ideal growing environment by regulating and monitoring temperatures and humidity levels. Talk to a Polygon representative today to learn more about how temporary climate control works in conjunction with greenhouse lighting and irrigation systems to optimize plant growth.

[ProFlowers via CC License 2.0]

Photo from ProFlowers

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