Gardening Vivian | 08 Apr 2010 05:13 am

The Importance of Heat to Hydroponics Systems

Photosynthesis, which is essential to all plant life, can only occur when the atmosphere in your hydroponics system is sufficiently warm. Should the temperature fall too low or should it fluctuate too much throughout the course of a day, photosynthesis may be stunted, incomplete, or not occur at all.

The temperate conditions to which many plants are accustomed has a great affect on how they grow in a hydroponic system. Plants developed in a way that made them dependent on a supply of moisture in the air and on temperatures that were usually rather high. Some plants evolved to be much hardier and survive in extreme conditions but the average hydroponic grower wants to set up their hydroponics systems so that their plants don not have to struggle against excess heat or cold. If the area around your plant is too cool, they may grow more slowly or cease growing altogether. Use a common garden thermometer to take a series of readings in your grow room. Take a reading in the morning, the afternoon, and at night so you have a better understanding on how these times can affect the temperature of your plants.

Most plants are able to thrive when the daytime temperature drops to no more than sixty five degrees Fahrenheit, though it would be preferable to keep it in between seventy and seventy five degrees Fahrenheit. Plants are accustomed to having the temperature at night drop somewhat significantly, but even then you should not let the temperate drop to less than fifty degrees. If temperatures drop too low, your plants may start to hibernate and photosynthesis will be adversely affected.

If you believe that your plants would benefit from raised temperatures, the easiest and cheapest way to do that is to literally raise how far off the ground your plants are growing. Since heat rises, the hottest part of any grow room will invariably be the ceiling. So consider placing those plants on a tall stand or hanging them from the ceiling. If you believe your plants are suffering from excess heat, try placing them on the floor. Too much heat will affect oxygen uptake. The most obvious sign of excess heat in your grow room is root rot in your plants.

Another more effective, but more costly way to regulate the temperature of your hydroponics systems is to purchase cooling fans. A well-placed cooling fan can be an excellent way to keep both you and your plants comfortable especially when you are using light bulbs that produce a lot of heat. In cooler climates, purchasing one or more small oil filled electric radiators will help maintain the warm temperatures that your plants thrive on. It is also important to remember that your plants will actually benefit from a small drop in temperature when you turn off your grow lights. Warmth is perceived by the plant as a sign to continue producing energy through photosynthesis. When there is no more light present, but there is still a lot of heat, this can send mixed signals to the plant, and it may affect photosynthesis when you turn the grow light on again the next day.

Michael Straumietis is co-founder of Advanced Nutrients and an expert on hydroponics, plant nutrition & soil sciences. He markets, reviews and publishes his knowledge in short original papers with a focus on soil-plant interactions. If you would like to know more about hydroponic systems, read the feature article in the hydroponics gardening section at

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