Archive Article: January, 2010
Understanding what exactly makes your favorite plants tick will give you the insight you need to supercharge the natural process for faster growth and bigger yields.
Nature has created the perfect internal and inherent growing system within plants. Some growers using advanced crop feeding programs may already be accelerating plant growth, while not fully understanding the process that is working to their benefit. It is the intention of this article to shine some light on how the photosynthetic process(es) work and how they relate to modern indoor growing, practices that include artificial lighting, elevated carbon dioxide levels and intensive crop feedings.
Plants are considered to be “autotrophic,” basically meaning that they create their own food. They do this through photosynthesis, which translated means “to put together with light.” There are three foundations to photosynthesis:
1. Photosynthetic activity – the capturing of light energy to combine carbon dioxide (in air) and water (in soil) to produce glucose; the chemical energy that is used to fuel all the necessary internal reactions for plants to grow. In simple terms, in the presence of light plants’ manufacture the carbohydrates they need to do “work.” Oxygen is a by-product of this process.
2. Respiration – this mostly occurs in the “dark” phase. Plants “burn” the carbohydrates they create during light reactions in the presence of oxygen to send the energy through the plant’s internal “wiring,” which is a network of proteins/amino acids to supply a variety of functions with the free energy they require. Carbon dioxide is a by-product of this process, making it a “mirror” reaction to the photosynthetic reaction, as above.
3.Transpiration – occurs at higher rates during the light reactions/photosynthetic activity. This relates to the loss of water vapor through the leaves, as water is transported from the growing medium with nutrients, through the roots. The nutrients are delivered into the plants, while a portion of the hydrogen and oxygen ions (from H2O) are assimilated through the plant. The majority of the water taken up escapes the plant through the leaves. Water pressure (turgor) inside the plant is what gives plants their rigidity and structure; as plants are after all, “bone-less.”
Light Energy = Growth: Healthy plants with ample CO2, water and nutrients will continue to photosynthesize under bright light conditions.
One of the most important things to understand about how these processes work on an individual basis, and as they do in harmony with one another, is that they need to be maintained in a balanced equation.
For example, the chemical equation in photosynthesis can be given as:
So if one of the pre-cursors in the reaction is lacking, for example, the plant has only three units of carbon dioxide relative to six units of water in the presence of bright light (radiant energy), the reaction can only work as high as a rate that three units of carbon dioxide will allow, with the remainder of the light and water being “wasted.” In fact, it may create a situation that is more than just inputs being “wasted,” it can actually create situations where the plant is running at a deficit.
In other types of situations, common to indoor gardening, when temperatures climb above 85°F, the rate at which respiration occurs (the burning of carbohydrates for energy) can exceed the rate of photosynthesis (creating carbohydrates). This creates a situation where by some definition, the plant is “working itself to death.”
Very bright light conditions are easy for indoor gardeners to supply using HID (high intensity discharge) lighting sources. This is usually the factor that creates an “imbalance” in the equation and relationship between the photosynthetic process, respiration and transpiration. The plant is saturated with intense light energy, while other factors such as carbon dioxide, temperatures, minerals and vitamins required by photosynthesis, etc. are not available in the same abundance. This imbalance puts the plant in a situation similar to excessive temperatures where the plant is working itself to death.
Bear in mind that modern indoor growers are putting incredible demands on the super-strains of plants that are cultivating. In nature similar types of crops may require four to six plus months to reach maturity in natural settings. Indoors, growers are driving the same types of plants to reach complete maturity in two to four months. That equates to twice the work that is required by the plant on a day-to-day basis! The demands placed on the plants by the environment supplied by the indoor grower are astounding when you consider the time frame it takes the crop to reach maturity versus in natural settings.
"Nature has created the perfect internal and inherent growing system (photosynthesis) within plants."
So how exactly are we accomplishing this incredible feat as growers? Well, those of us who accomplish it the most successfully are driving and fuelling this natural process through improved crop growth technologies. As growers, we are supplying an abundance of the factors necessary and in the correct balance to amplify the plant’s natural and inherent responses.
In today’s day and age, it’s easy to provide optimal light durations (day lengths) and incredible lighting intensities using readily available artificial lighting sources. HPS (high pressure sodium) lamps do a good job of producing lots of lumens, although they are not as rich and complete as the sun in spectrum. They also produce a lot of heat, which can be detrimental to plant growth, as we discussed earlier.
Air- and water-cooled lighting fixtures can drastically reduce the excess unwanted heat created, removing it at the source, rather than overheating the plants. Artificial lighting spectrums can be improved by using modern HID lamps that have their spectrums enhanced to stimulate plant growth rather than illuminate parking lots. While they are no match for the sun’s “solar nutrition,” they are an improvement.
High output T5 fluorescent lights can be very rich in spectrum, and are ideal for stimulating healthy plant growth in the earlier stages, and can in some instances be used to raise plants to maturity.
Heavy Loads: When plants are able to manufacture adequate supplies of chemical energy, heavy fruit loads may develop.
LEDs perhaps offer growers the best opportunity to provide very exacting light wavelengths for different growth phases. At present, it would appear that the technology itself is “smarter” than we are; growers and LED manufacturers alike are learning about what will work best at different growth phases, as LED fixtures can be tailored to provide very exact wavelengths of light. The technology goes far beyond the capabilities of what HID lighting can offer. LED diodes emit very negligible amounts of heat, reducing cooling requirements and costs. The fact that they run cooler allows for more efficient supplementation of carbon dioxide levels in the growing environment for faster growth rates and bigger yields, due to reduced air exchange requirements.
Carbon dioxide (CO2) for light reactions is usually the most limiting factor in indoor gardens, assuming cooling requirements have been accomplished with a high level of control. If growers are able to maintain optimal temperatures during the intense light cycle, plants will grow at noticeably increased rates when elevating the levels of carbon dioxide in the growing environment. Carbon is the biggest component in the dry weight of plants, and elevating carbon dioxide levels can have a direct effect on increasing dry plant weights at maturity. Fermentation, releases of bottled CO2, and generation of CO2 through gas-fired combustion are common methods growers may use to elevate CO2 levels in the growing environment for better results.
All of the areas discussed above are “exogenous” or external factors that can be controlled by the grower through the use of specialized mechanical equipment. Now what about the internal or “endogenous” reactions that are going on inside of the plant? This is where the real magic happens.
Modern, advanced nutrient manufacturers have dissected the internal responses and materials required to fuel and sustain high rates of growth for intense indoor growing environments. These “ingredients” have been discovered, refined and blended into exacting ratios to create crop feeding programs that help meet and stimulate the tremendous functional demands placed on crops by modern indoor growers.
The end result of the photosynthetic response is glucose, which is “burned” during respiration to release energy. There are crop feeding supplements that are able to supply relatively available sources of carbohydrates to plants when they are applied accordingly. This means that for example, in instances when the rate of respiration is exceeding the rate at which photosynthesis (during high light and warm conditions in the presence of CO2), the plant’s reserves of energy may not run at a deficit, allowing the plant to continue growth, rather than “shutting down” to prevent exhaustion or even plant death.
Consider high intensity activity in humans such as long distance running. Athletes load up on carbohydrates to provide their bodies with the necessary levels of energy to meet the high demands of the task they are placing on their body’s energy system. During the activity, runners breathe harder, requiring more oxygen. Plant growth has a similar demand for vital gas, although it is carbon dioxide rather than oxygen. If there is insufficient carbohydrates or necessary vitamins, minerals, gases, etc., the runner will finish poorly, or may not even finish at all in some instances. This is the case with plants.
After strenuous physical demands plants, like athletes, also require proteins to repair and build new tissue and energy transfer ways to supply and direct energy. This is where L-amino acids for crops come into play. Plants normally have to manufacture amino acids and other forms of reduced nitrogen to help build new tissue and create the energy transfer ways.
Growers who supply crop feeding supplements that contain broad spectrum of L-amino acids including lysine during times of great mass gains, for example in the peak bloom phase, are in fact providing crops with the necessary materials to get bigger faster. The plant will not have to work as hard to manufacture these proteins, as they are supplied at some level of availability. Note that microbes in beneficial bacteria and fungi help to improve this process. This would be similar to an athlete drinking a well formulated protein supplement after strenuous physical activity versus eating a steak. The athlete’s body will more readily assimilate select proteins in their ideal ratios, rather than expending energy to convert proteins supplied in cruder forms such as meats, to forms that the body can use to build and repair tissue. This quickly translates into greater mass gains in shorter time frames; something every indoor grower should aim to accomplish.
Vitamins, minerals, enzymes and other co-factors also play a strong role at which the rate of all the reactions required by the plant to grow may occur. Most minerals are supplied to the plant through the roots, carried up with water in the transpiration process (loss of water through leaves). Without these vital minerals, and in their correct ratios for the type of crop being grown, the rate at which photosynthesis may occur will decrease. This is why it is important to choose your crop nutrients carefully. The correct balance and a high level of availability under a wide range of growing conditions should be of careful consideration.
Plants typically manufacture their own vitamins, enzymes and co-factors, although in nature it has been demonstrated that these substances may also occur in the growth medium and be transferred to the plant for uptake and assimilation for functions. Again, this is typically assisted through beneficial microbes, which are available in modern formulations to inoculate indoor crops. These beneficial vitamins, enzymes and co-factors can also be supplied through specialized and well formulated crop feeding additives more or less directly to the plants.
Similar in concept to supplementing the crop with carbohydrates and amino acids for higher rates of growth and mass gain, additions of vitamins, enzymes and co-factors will benefit the crop. By using specialized crop feeding programs designed to promote bigger yields and healthier plants grown under intense artificial light and elevated carbon dioxide levels, the grower is helping to “balance” the plant’s internal equation that is dictated by the three key foundations to plant growth: photosynthetic activity, respiration and transpiration.
Now that you know more about what exactly is making your favorite plants tick, you may be able to improve your yields, growth rates and crop quality by respecting and maintaining an understanding of these very important principles. Keep them in mind when constructing the ideal environment for your plant with regards to light intensity and quality, temperature and CO2 levels.
Once you can maintain and manage the optimal external environment, your crop can take advantage of full spectrum feeding programs that have been designed specifically to satisfy the needs of your plants being grown in an accelerated environment. In fact, some crop supplements will help your plants to maintain a higher degree of health and growth rates, even in less than perfect environments. However, supplements are not a replacement to creating the optimal growing environment for your favorite type of plants. It is about harmony, balance and respecting the perfect inherent mechanisms for growth that nature has developed, and with understanding we may achieve our own personal yield of dreams.
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