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Grow light spectrum question

Pivitol

Pivitol

Hi, my other hobby is aquariums so I have different spare parts and lights lying around. On my big tank I run a fixture with dual MH bulbs and 4 T-5 bulbs so I have bulbs to spare, for my grow tent I recently purchased a HydroFarm 250w HPS/MH fixture. I know the blue light spectrum is important in the growth stage of plants. My questions is the MH bulbs I use for my aquarium are 20,000k which put out a very blue light, would these work well for the growth stage and then switch to the HPS for the flowering? 
 
Powelly said:
You want the temperature to be 4000-7000k
20,000k is hard ultraviolet and will harm plants
 
Don't worry about veg/flower cycles as this is typically something you only need to worry about with growing cannabis.
 
Here is more information:
http://sunmastergrowlamps.com/plant-science/
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Good to know definitely don't want to microwave my plants. What about supplemental lighting with t-5's. I have spare t-5 fixtures that I could use, with aquarium t-5's they are not rated in kelvins but nanometers, i.e. an atinic bulb which is very blue typically runs at 420nm which is right in the sweet spot for photosynthesis for the blue spectrum. If used with a full spectrum MH or HPS bulb would you foresee any advantage or just wasted electricity? 
 
Pivitol said:
Good to know definitely don't want to microwave my plants. What about supplemental lighting with t-5's. I have spare t-5 fixtures that I could use, with aquarium t-5's they are not rated in kelvins but nanometers, i.e. an atinic bulb which is very blue typically runs at 420nm which is right in the sweet spot for photosynthesis for the blue spectrum. If used with a full spectrum MH or HPS bulb would you foresee any advantage or just wasted electricity? 
Click to expand...
 
Split it 50/50
 
2 420nm/6500k T5
2 600-650/2700k T5
 
You want a full spectrum. If you already have some T5s then it's cheaper and more economic to simply buy the other end of the spectrum. If you don't have anything though then you may as well just get a full spectrum lamp
 
In aquariums one usually also uses grolux lamps, the lamps that emit a light that looks pink to the eye because they emit mostly red and blue light. Those are also suitable for plant growing. They work fine for me.
 
This should be posted in "Grow Tech" where :   Discuss lights, heaters, irrigation systems, greenhouses, and DIY solutions. Show off your inventions!
 
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