Learn How - Hydroponics and Greenhouse Gardening
By Charlotte
By: Charlene Rennick
Although the jury is still out on whether or not LED bulbs are a confirmed improvement over regular hydroponic grow lights, currently the LED bulbs have several distinct and known advantages.
In the absence of side by side testing against Metal Halide and High Pressure Sodium bulbs, some benefits of substituting LED bulbs can be appreciated in a hydroponic garden.
[Read more…] about Introducing LED Bulbs to Hydroponic Gardening Systems
By Charlotte
By: Charlene Rennick
LED stands for Light Emitting Diode. This kind of bulb has been popular for decades to illuminate clock displays, stereo equipment, flashlights and outdoor-lit advertisements. Because they emit more light per watt than regular incandescent light bulbs, they have a potential to save hydro dollars and excess energy consumption.
Recently, advancements in LED technology have produced more sizes and shapes of LED bulbs increasing their application base as a regular household lighting device. They leave less of a carbon footprint than an incandescent bulb and do not produce much heat when lit. The most widely-known benefit of LED bulbs is that they produce light for a longer period of time. LEDs have an average lifespan of 35 000 to 50 000 hours as opposed to 1000 to 2000 incandescent or 30 000 fluorescent hours.
LED bulbs have several less obvious advantages. They can be used more efficiently as a colour bulb than other types of lights because they do not require additional filters to change the hue. Because of their shape, they lend themselves more readily to being direction-focused; whereas, incandescent bulbs need additional accessories to train the light emissions. LED bulbs have a solid structure; they are not particularly delicate and are not as susceptible to electrical surges or shocks as incandescent, fluorescent and halogen bulbs. For lighting that requires frequent on/off phases, LED bulbs are more resistant to the wear and tear than fluorescent and incandescent bulbs. This makes LED bulbs a better bet for use with a timer. In addition, LEDs lose brightness over a long period of time. This gradual dimming has the advantage of providing a warning period before a replacement will be necessary; it avoids the risks associated with an abrupt burn-out. With some applications, the sudden absence of light creates environmental damage or human safety hazards due to spontaneous darkness. LEDs light up quickly and are mercury-free. Overall, they perform better over time than fluorescent, incandescent and halogen bulbs.
Known disadvantages of LED bulbs are that they are more expensive at the outset to purchase without considering their long-term savings advantage. They cannot be used in dimmer switches and can be subject to extremes in temperatures (http://en.wikipedia.org/wiki/Heat_sink). Another drawback is that LED bulbs generate light from a different part of the spectrum. This causes objects to be perceived as an altered colour from that which would be produced if the same object was viewed using natural sunlight or incandescent light. Sometimes, the electrical current source may need to be adjusted to accommodate the LED bulb. Presently, there is some concern that the blue light content of LEDs may conflict with safety regulations. This issue is called the blue-light hazard and it may have a negative effect on the eyes.
In addition to their longer life span, energy saving benefit and reduced noise, LED lights eliminate the need for a ballast which is necessary to control the voltage. If both Metal Halide and HPS bulbs are in use, more than one type of ballast is needed; thus, substituting LED lights potentially eliminates more than one piece of equipment.
The use of LED lights as a substitute for HID grow lights in indoor gardens looks promising, however its practical application for hobby gardeners is probably a few years away yet.
By Charlotte
The success of your garden is directly related to the quality of light provided to the plants. If you are using natural daylight for your hydroponic garden, then you have the best possible light source available. Unfortunately, the amount of daylight available varies during the year and it is not possible to successfully grow certain plants year-round without supplementing daylight. If you are using artificial light provided by sources such as metal halide or high pressure sodium (HPS), you need to remember a few things:
LEDs are emerging as a new form of light source in the hydroponics world. They offer the promise of decreased energy usage as well as better sizing possibilities. This is somewhat new to the scene and not recommended at this point.
For further information, see our article on grow lights.
By Charlotte
By: Charlene Rennick
Light is more than just bright, white space. It is made up of all the colours in the rainbow. An easy way to remember all seven rainbow colours is to introduce you to Roy G. Biv. The letters in his name stand for red, orange, yellow, green, blue, indigo and violet.
To see what colours are in a beam of light, you have to bend it. This is called refraction. You can put the colours back into a beam of light by spinning them quickly in a circle.
Here’s how to make a light beam at home:
What you need:
Pencil
Scissors
White cardboard or Bristol board
Crayons or markers
Ruler
Bowl or round object you can trace around to make a circle
Paper cup
Directions:
Trace a circle on the white cardboard and cut it out. Using the ruler, divide the circle into 6 equal sections.
Colour the six sections with the markers. Be extra careful to stay inside the lines and colour in all the white spot. It is important that the colours be thick, dark and even.
Poke a hole through the middle of the circle with the pencil and push the pencil part way through the hole.
Punch a hole in the bottom of the paper cup with the end of the pencil.
Turn the cup over on top of a piece of paper.
Push the pencil through the hole so the pencil point just rests on the paper. Adjust the colour wheel so it is about 2 cm above the cup.
Spin the pencil quickly between your palms.
What do you see?
The colours on the wheel are the colours that make up white light. If the wheel spins fast enough, the colours will blend together and the wheel will look white.
By Charlotte
by: Charlene Rennick
Light is not white, but is made up of many colours. When light is refracted, it is bent which exposes the colours inside the ray of light. The beams of red, orange, yellow, green, blue, indigo and violet become a dazzling visible array.
For hydroponic use, light should come from the red and blue beams. This kind of light, called PAR (photosynthetically active radiation), is the next best thing to natural sunlight. Fluorescent lights are adequate for plants that do not need much sunlight, but will not help produce anything other than greenery. To really imitate natural sunlight, a range of bulbs that represent the colours of the spectrum will provide the best hydroponic plant growth.
High Intensity Discharge (HID) lights are the best kind for hydroponic use. They are stronger than regular fluorescent lights and provide the maximum amount of PAR for the amount of wattage. There are two types of HID lights: Metal Halide (MH) is from the white/blue part of the spectrum, and High Pressure Sodium (HPS) is from the orange and yellow part of the spectrum. MH is useful for regular leafy growth and HPS will promote bud growth and flowering. MH/HPS conversion bulbs are available which allow switching back and forth with ease.
Hydroponic light is measured by wattage per square foot. Photosynthesis will occur if the wattage is around 20 watts per square foot for low light plants and as high as 50 watts per square foot for vegetation that needs a higher intensity.
The tips of stems and tops of leaves can become scorched if the hydroponic lights are too close to the plants. If the wattage is low or 250W, the bulb should be 12-14 inches away or 16-24 inches from a 400W bulb and have 24 inches between the plant and a 1000W light.
The colour of paint on the walls and ceiling makes a difference too, with lower gloss white paint making the most of your indoor lights. Mylar is even more reflective if you want to get serious and don’t mind the look.
Hydroponically grown plants need roughly 16-18 hours of light per day for normal growth. Some plants need extra light followed by a period of darkness in order to force blooms to flourish inside. Timers can be purchased to help alleviate the need to remember the lighting cycle and to allow you some freedom from your light switch.
Using HID lights extends the growing season in the fall and allows a head start in the spring, but don’t get too carried away! Extending the light beyond 18 hours a day will wear your plants out and cause an untimely demise.
By Charlotte
By: Charlene Rennick
All plants need air, light, water and minerals to thrive. Each one of these elements has reliable qualities that make it able to sustain plant growth. Depending on the type of plant, the air is dry or humid, the light is strong or weak, the water is plentiful or sparse, the temperature is specific and the soil is acid or alkaline.
How Much Light is Enough for Hydroponic Gardening?
Outdoor gardening is pretty self-sufficient in terms of regulating the air and light flow. There’s not much you can do to adjust wind and sun; however, hydroponic gardeners have to provide air and water flow, intensity and interval of light and the quantity and range of minerals. Without this, photosynthesis will not occur. Photosynthesis is as important to a plant as digestion is to a human.
|
All plants are green. Even when it is another colour and no green is visible, there is always a layer of green chlorophyll underneath.
|
|
Photosynthesis begins when the right kind of light hits the green pigment in the plant’s leaves called chlorophyll. When the light interacts with the chlorophyll, it mixes with carbon dioxide and water to make oxygen and sugar. The sugar is oxidized through a process called respiration, which makes carbon dioxide and water into energy. Other micro-nutrients present inside the growing medium are absorbed by the root system. These contribute to the plant’s strength. The by-product of photosynthesis is oxygen which the plant releases into the atmosphere. The fact that humans require oxygen to survive makes the human-plant relationship, symbiotic.
Is Hydroponic Growth Complicated?
When the plant respirates, it emits carbon dioxide. Tiny openings on the underside of the leaf, called stomata, absorb carbon dioxide and emit oxygen or vice versa, depending on whether the plant is photosynthesizing or respirating. Because carbon dioxide exists in the atmosphere in very small quantities, the stomata have to be wide open during the hours that the leaves are absorbing light (photosynthesis). If the humidity is too low, this can cause evaporation of the plant’s moisture. The root system needs extra water to compensate for this. If water is sparse, the leaves will suffer and look wilted. This is called transpiration. To avoid transpiration, hydroponic gardens need an atmosphere that is humid enough for the plant to achieve a balance between respiration and photosynthesis.
Sounds complicated? It isn’t really. As long as you have a room thermometer and a hydrometer to track the heat/humidity levels in the air, you can keep the environment in the range for your type of vegetation and the plant will do the rest of the work.