Tutorial - Achieving Maximum Yield

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Achieving Maximum Yield

Light is the primary source of yield for any plant. Restrict the amount of light a plant gets and you restrict the eventual yield that is available to you at harvest. In indoor growing the light available to the plant is restricted by the wattage of light. As there is only a limited amount of light energy available every effort must be made to maximise the light energy your plants receive. This can be achieved in several ways.

As it is easier, cheaper and less time consuming to achieve maximum yield with HID (High Intensity Discharge) lamps this will be the focus of these tutorials.

Your light must be as close to the plants as possible without injuring the plants, this ensures no light energy is wasted. Light loses energy the further it has to travel. For every unit of distance light travels it loses four units of energy. While it is important to keep the light source as close to the plants as possible, it must not be at the expense of the spread of the light. A middle point between light intensity and spread must be achieved to give the largest area of optimum light coverage.

When possible it is advisable to buy the best shade you can afford. As yield is always restricted by the light available to the plant every effort should be made to use the available light energy in the most efficient manner. Your shade should be one that focuses the most light towards your plants over the largest area. One of the best shades currently on the market is the Eco Technics 'Diamond' reflector, available in 400 watt and 600 watt versions.

For smaller set-ups a dual spectrum (red and blue light) sodium bulb is more than adequate. This gives the most efficient and economic results for the price of one bulb. Larger growers with multiple lights may use metal halide bulbs during the vegetative stages to develop more compact growth. This only becomes a relevant factor when pushing for small percentage additions to your overall yield by ensuring the fastest turnarounds for your crop.

Light intensity from the bulb will start to diminish from about 9-12 months onwards. This is when larger growers will replace their light bulbs. Smaller growers can easily squeeze out another six months if needed.

The lighting ballast ignites the gases within the bulb which in turn emit the light energy that is used by the plants. Ballasts come in two forms magnetic and electronic. Magnetic ballasts have a longer track record and are proven to work more consistently than their electronic counter parts. Electronic ballasts are currently less reliable and more expensive but produce less heat and are slightly more efficient.

Maintaining a consistent environment provides your plants with the maximum amount of time to grow at the fastest rate. The longer the optimum environment is maintained the higher the yield.

Chemical reactions in the plant require energy to proceed at the maximum rate. Keeping the temperature of your grow room at a consistently warm level allows the plant to maintain its chemical reactions at the optimum rate. While the lights are on a good temperature to maintain is 24°C. While the lights are off a good temperature to maintain is 18°C. Your plants will grow out with these ranges but going beyond 30°C and below 12°C will generally limit the growth rate of your plants.

The air in your grow room provides Carbon Dioxide (CO²) to your plants, which is essential to plant growth. Plants use Carbon Dioxide to grow and produce Oxygen as a by-product of their chemical reactions. These gases need to be replaced and removed from you grow room to ensure the fastest growth rates.

Using an extractor fan introduces more Carbon Dioxide (CO²) into your grow room and removes the unwanted Oxygen (O²) that the plants give out. A constant fresh supply of Carbon Dioxide (CO²) will provide an environment that ensures the fastest growth rates. Extraction also helps maintain a consistent optimum environment leading to a consistent optimum growth. The removal of excess heat and humidity are also key benefits of good extraction.

Humidity is the level of water suspended in the air. Plants give off water and Oxygen (O²) into the air as part of their chemical reactions. Growing inside with HID lights produces a warm environment that combined with high humidity provides an ideal environment for things like fungus mould to grow. Given the right environment fungus mould can devastate plants and wipe out your crop.

The addition of extra Carbon Dioxide (CO²) above the natural levels can increase the rate at which plants grow. This is only true to a certain extent. With an increase in Carbon Dioxide (CO²) levels the plants must be given more nutrients and the environment must be heated up to allow faster chemical reactions. To enable faster growth rates these other factors must be controlled with a high degree of accuracy otherwise the addition of Carbon Dioxide (CO²) is a complete waste. Good extraction using a temperature controlled fan will do just as good a job.

NUTRIENTS:

Basic nutrients generally come in one part, two part or three part. The more basic nutrients come as a one part. They tend to be produced by a chemical process in a chemical vat and are the simplest to use. More complicated nutrients come in two or three parts and require more time and effort to use but tend to produce better results in the long term.

One part nutrients like Growth Technology Ionic are the most basic and tend to produce the most basic results. They require less work and are generally buffered for pH, which generally means more chemicals are added to stabilise the nutrient solution.

Two part nutrient like House and Garden A+B are separated to produce more stable nutrients with less chemical additives. House and Garden nutrients are non-pH buffered which means less stabilisation chemicals are added leading to a more natural nutrient solution. House and Garden nutrients require more work than most nutrients but when combined with their additives and flowering boosters produce the best results. These nutrients are about as close to organic as is possible in hydroponics.

Three part nutrients like Advanced Hydroponics of Holland are a good start for the slightly more experienced growers. The three parts and can be tailored to the needs of your plants. If you use cuttings from the same mother plant all the time you can experiment with changing the ratios of the nutrient to suit your plants specific needs. It is buffered for pH, is chemical based and will produce a less natural harvest.

There are many additives on the market and it is hard to justify most of them. The additives listed below are the ones that have a proven record of increasing plant health, growth and yield. There are alternatives to all the additives below, but these are the ones have been found to have the best track record.

When growing plants most growers concentrate on the visible part of the plant. To achieve maximum yield you must learn to increase root growth at every stage of development. As nutrient uptake depends on a good healthy root structure growth must be stimulated at the earliest opportunity. Providing your plants with a boost

House and Garden Root Accelerator is a highly concentrated and is an excellent root stimulator. Its price is high but when combined with its high concentration (1:1000), relatively low period of usage (experienced growers should only need to use it for 1.5-2 weeks and will not need to change their entire nutrient solution in this time) it provides an outstanding boost to your plants roots.

Multi Enzymes by House and Garden is a mid flowering stimulator that is used from the start flowering until the last three weeks of flowering. It contains enzymes that break down old roots. Micro nutrients that encourage cell splitting and overall plant development. Multi-Enzymes can also be used to increase the health of mother plants.

For the last three weeks of flowering House and Garden produce Bud XL. Bud XL encourages the transfer of stored sugars in the leaves into the flowering parts of the plant. The vitamins, proteins and minerals contained in Bud XL expands the cells in the flowering parts of the plant allowing more sugars to be stored in the flowers and fruits. This in turn leads to higher production of fruits and flowers.

Boosters

During the growing and initial flowering periods maximising growth and efficiency of light use is of utmost importance. When growing larger less numerous plants it is important to fill the area under the light with as much plant as possible. Using the right growth booster can help fill the spaces between plants. Nitrozyme from Growth Technology contains cytokinins which promotes rapid cell splitting and overall cell growth. When used in combination with a wetting agent as a foliar spray it produces explosive growth. This closes the gaps between plants and increases leaf coverage, which in turn increases the efficient use of available light. Nitrozyme is best used at the end of the growing phase before flowering.

During the flowering phase your plants require higher levels of Phosphorous (P) to Potassium (K) to form heavy flowers or fruits. These elements can be provided to your plants in a variety of ways. Using flowering boosters can dramatically increase yield by increasing volume and weight.

The standard flowering booster is has a Phosphorous to Potassium ratio 13/14 and is commonly called PK 13/14. House and Garden produce a PK 13/14 additive called Top Booster. Top Booster contains Phosphorous and Potassium in a ratio of 13/14 but also contains micro nutrients such as iron and magnesium. Use any PK 13/14 additive for three to four days three weeks before harvest. The is the time when your plants stop any upward growth and concentrating all their energy on flowering.

Shooting powder from House and Garden is a flowering stimulator used after PK 13/14 until the end of flowering. When using the complete House and Garden range the basic nutrient is reduced to its starting level and shooting powder is added as a top up. During the first week of use Shooting Powder is used at half strength. In the following two weeks before harvest it is used at full strength. Great care has to be taken when using Shooting Powder as it is very strong. The accuracy of pH must be monitored and checked regularly as it requires greater additions of pH adjuster to be used properly. When used well Shooting Powder can produce significant increases in volume and weight, but must be handled with care. Shooting Powder is best used in conjunction with a pH and nutrient meters.