Dispelling Some Common Hydroponics Myths

[StonermanDan]

yeah got a link to this article in a hydroponics shop subscription thing i have, thought i'd share it with you guys, hope you find it useful/informative/an interesting way to waste 5 minutes of your life

http://www.growell.co.uk/index.php?pr=48&r...il24&d=GRO55EZR

 

 

 

 

Dispelling Some Common Hydroponics Myths

 

 

Hydroponics growing is riddled with myths and false statements which get spread around the growing community. Let us put you straight on a few things and dispel some of the growing myths.

 

 

 

Hydroponic growing is riddled with myths and false statements which get spread around the growing community in the ever elusive quest for extra yield. Some of them stem from lack of growing knowledge whilst others are created by unscrupulous companies attempting to sell products which don’t actually work.

 

Water temperature – Your nutrient solution should feel COLD at 21oC NOT WARM. 21 degrees centigrade is the ideal temperature, it’s warm enough to stimulate good growth while cold enough to be able to carry the maximum amount of oxygen (O2) for our purposes. As the water rises above this temperature the water can carry less and less oxygen.

 

Timers on NFT systems – Once the roots are out of your 3” cubes or baskets, you should run your nutrient pump 24 hours a day, certainly never have it off for more than 15 minutes at a time, even during lights off. Otherwise brown coloured cell damage may occur on the root surface as the cooling caused by evaporation of moisture off the roots damage it’s surface. It’s often better to run the solution all the time, this also helps maintain constant root zone temperature.

 

CO2 and Carbon in your nutrient solution – The vegetative leafy part of the plant above the surface feeds on Carbon dioxide. The roots feed on and in association with Oxygen. There is no benefit to putting carbon or carbon dioxide into the nutrient solution on it’s own. However some of the additives do contain some carbon based compounds in association with other ingredients.

 

Nutrient meter reading – Because everybody has tap water with a different start cF and the fact that plant needs vary from room to room, it’s hard to just give people optimum readings to aim for. cF meters are more useful for maintaining the correct strength on a day to day basis in re-circulating hydroponic systems once the optimum has already been determined. After evaluation of the plants reaction to the strength, small adjustments can also be made using the meter.

 

Feed strength – Not all plants feed the same amount, not even close relatives of the same varieties so don’t believe anyone who tells you otherwise! Environmental conditions also affect feeding, more light = more food. As a general guide use 1/4 to 1/2 strength hydroponic nutrient solution for young plants, and ½ to ¾ strength for larger plants. Most manufacturers full strength is equivalent to about 1200ppm or cF17 (with water cF 0), this is good for most species and varieties of plants. Some tomatoes may need a bit more, and lettuces would require a chunk less but you realy need to experiment with the specific variety of plant you are using to determine the optimum feed strength.

 

Leaf colour loss and associated rusty spots – These two things, particularly when associated together are usually caused by some environmental factor and NOT a nutrient deficiency. Unless you are seriously underfeeding or overfeeding, the feed strength you use will generally not be the cause. It is more likely to be the light too close, nutrient too warm, not enough air exchange, too cold nights, wind burn, grow room too dry or another environmental factor. Don’t always believe the worst and assume that your feed strength is wrong.

 

Stretching – Plants can stretch or elongate. They may do this if there is not enough light, they may also do this if they have too much light or heat because the light is too close. Or it may be just genetics. There is no single reason that can be pinpointed as the cause of your plants stretching – don’t believe anyone who tells you there is!

 

Input Air – As a hobby grower, for the best results, ideally use indoor air as input air for your grow room and expel to the outside. Outdoor fresh air inputted into the grow room can cause temperature, humidity and bug problems. Indoor air from a house has a better temperature and higher CO2 content, the extracted air should then ideally leave the building or be extracted to another room or area. Don’t assume that input air from outside will be “cleaner” or better for your plants – it’s simply not the case!

 

Air Cooled Shades – In line fans attached cool shades/ Jetstreams/ air cooled lights must blow through the shade. Sucking air through the shade will NOT work as well at cooling your lamp.

 

pH Adjustment in re-circulating systems – in re-circulating hydroponic systems including gro-tanks and particularly when using systems with rockwool slabs and hard water, the pH will often rise on a daily basis. Don’t adjust it right down every day or you may end up with nutrient lock out from excess phosphoric acid. Instead don’t be afraid to let it drift up for a day or two, this may be the lesser of the two evils. Constant adjustment will damage your plants, not help them!

 

Cold – Too cold a nutrient solution or air temperature at night (lights Off) can seriously affect your yield. Try to keep water and air temperature up to 21 degrees centigrade to avoid damaging your yield