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DIY Hydroponics - Indoor Gardening
Indoor gardening with hydroponics is more challenging than gardening out of doors. There are many more factors that must be controlled for your hydroponic garden to grow successfully. There are many reasons why a gardener may prefer to grow indoors, not in the least being the ability to control the photoperiod and grow crops out of season. You have the ability to control temperature, day length and avoid prying eyes, which can be an important factor for some individuals.
Choosing your New Growing Space
Indoor hydroponics can be conducted in spaces as small as a large cupboard. The smaller the area of the growing room the more care must be taken to ensure it is adequately ventilated. A larger area will have a greater tolerence as far as trapped heat and stale air is concerned. The best place for an indoor garden is a corner of your basement if you have one as it is a cool and out of the way location. Wherever you choose the ceiling should be at least five feet high.
Wherever you choose to create your garden consider ventilation and ease of lightproofing as well as more obvious factors like electricity supply and access to fresh water. The disposal of your used nutrient solution must also be a primary concern. Spent nutrient solution is high in nitrates and other salts and should not be poured down a drain or dumped in the same place outside if it can be avoided as the soil will become toxic. I fertilize my normal garden beds with my hydroponic garden left overs and have found the result to be very satisfactory. Even your lawn doesnt mind a dose now and then.
Prepare the Growing Area
Prepare the growing area by removing all items of furniture and anything that it is not necessary. The plants will increase the humidity of the room and anything that will absorb water will rapidly become mouldy. If there is carpet that you dont want to remove cover it with a plastic drop sheet so that inevitable spills will not be absorbed. Concrete floors are best. Light proof the room if necessary by covering the windows with black plastic. Its a good idea to leave heavy curtains in place to reduce the amount of light that the plastic needs to control and this has the advantage of looking like a normal window from the outside thus avoiding unnecessary attention. Completely enclose it from the inside with plastic though as curtains can get mouldy very quickly. Ideally the room should be painted white or lined with reflective mylar to reflect light back to the plants. If you have a large room but only using a small part of it consider making some partitions (like portable walls) that can enclose the garden area and cover them in white paint or better still reflective mylar. If you are gardening in a cupboard the lining the inside with mylar will be perfect.
Plan your Ventilation
Ventilation is very important to the indoor garden as stagnant hot air will kill your plants very quickly or in the very least promote mould. You need an inlet as well as an outlet and there is flexible plastic ducting available from most hydroponics shops that will allow you pipe the air as required. Draw the air in close to the ground by one vent hole ducted to avoid light intrusion. Pump the air out using a vent fan or air shifter in the ceiling or built into the top of a door. When light proofing vents remember that light travels in a straight line so the plastic ducting should be shaped into a curve. Venting directly into a roof cavity with a kitchen or bathroom exhaust fan is a common solution. Although there are different schools of thought regarding how often the fan should be run I recommend it going 24 hours a day. Too much fresh air is unlikely to kill your plants however not enough will create problems. It doesnt hurt to be a fine mesh screen over your inlet and exhaust ducts to discourage pests from entering the garden.
Lights and the Photoperiod
Photoperiod is a very technical sounding word but all it really means is the number of hours of light that a plant receives over a 24 hour period. Most plants have a vegetative growth period and a flowering period. Some plants will not beginning flowering until the day length shortens. In summer in most places in the world the day length is 16-18 hours, the plant sees this day length as summer and grows leaves, stems and a strong structure in preparation for growing lots of flowers or fruit. In winter the day length may be only 10-12 hours and the reduction of hours of light is a signal to the plant that it is time to grow fruit. Of course not all plants follow this behaviour, it depends on what your growing. Zuchini will generally fruit with a long day however some other plants will need a change of day length to trigger flowering. Indoor gardening gives you this extra, sometimes very necessary level of control. The type of light you will use varies depending on your needs and the stage of growth that your plants are in. When plants are vegetative growth they tend to require light at the blue end of the spectrum, which promotes photosynthesis and thick leafy growth with good strong stems which is essential to support a heavy crop of fruit and create plenty of budding sites. In the flowering stage mosts plants prefer light from the red end of the spectrum which is used to foster the growth of large fruits or flowers. When using HID lamps such as high pressure sodium or metal hallide lamps use the rule of thumb of 30-50watts of power per square foor of garden space to determine the right number of lights and their wattages to use. There are three types of light that your average gardener will use.
Flourescent Lighting is quite commonly used for its gentle, even light distribution and many plants will grow quite successfully under them. They are very usefull for growing seedlings and striking cuttings however their effective distance is only 12-18 inches, further than this and the strength of the light diminishes as the plants will grow spindly trying to get closer to them. Most plants will tolerate a flourescent light just 3 or 4 inches above them without burning. Normal flouros are very rich in blue light and are most suited to vegetative growth however most hydroponic shops and aquariums stock grow tubes that are very rich in red light as well. The best combination to use is one normal flouro tube to one growlight. I have a friend who grows orchids and other delicate flowering plants in his lounge room under a number of two tube flourescent light fittings and they are exquisite.
Metal Halide Lamps are used in the vegetative stage when the plants are actively growing. They are considered to be a High Intensity Discharge or HID lamp and create a respectable amount of light for their given wattage. Like all HID lamps there should be at least 12 inches between the lamp and the plants to avoid burning them. A single 400w metal halide lamp with a decent reflector and mylar or white paint around the edge of the growing area can light an area of 10-15 square feet very effectively. Some gardeners do not use these however preferring to grow there plants to around the 24-36 inch mark under florescent lights and then move their plants straight to a high pressure sodium light for flowering.
High Pressure Sodium Lamps are used in the flowering or fruiting stage of growth and promote large healthy crops of fruit. They are also HID lamps and should never be less than 12 inches away from the plants or they may burn. A 400w high pressure sodium will light an area of 12 -15 square feet quite effectively with the help of good reflective surfaces at the gardens boundary.
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