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HPS and MH light, I hope I made finally made the right call


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  #1  
Old 04-02-2011, 04:20 PM
cable24601 cable24601 is offline
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Default HPS and MH light, I hope I made finally made the right call

At about 9 weeks in to this experiment I am a little disappointed by the results that I am seeing. Don't get me wrong, I have some great growth from my lettuce and dill but everything else is growing at a snails pace. In fact my tomatoes look like they have stopped growing all together. So what is the problem? I had a long conversation with the owner of my local hydroponics store and he thinks that I just don't have the amount of light needed to grow anything more than small leafy plants. As many of you know my goal is to grow all of the fruits and vegetables that my family's needs. In the last few weeks I have looked in to the expansion of my hydrofarm and knew that lighting would play a big roll.

The big question know is what to do about it. I chose led in the start do to the low power cost and heat. I then added on T8 florescent to the project to grow out some seedlings. Here are some of my impressions so far.

The 2 13 watt LED red blue panels have been above 4 4 inch dirt pots full of herbs. These have done a nice job of keeping me supplied with chives, oregano, and chives. The 4th pot is rosemary but not much action there. I am happy with these lights but wonder if I would get more from T5 HO.

The 1 240 watt LED 7 band panel only seem to cover a 1 foot by 2 foot square and once the plants got to 18 inchs high they started to die off near the bottoms. This thing will grow but I would need quite a few to work for what I want. If they did work as advertised this could have been a different story.

This bring me to high pressure sodium and metal halide. In the start I was against this type of system. I was thinking high power bills, heat and the cops stopping by to raid my tomatoes however when I look at it now I think alot of this is a misconception. Yes hps will be more power but not much and the heat will be more but that is nothing better ventilation can't deal with. As for the cops I would have to expand to using about 6 600 watt lights before I may get a visit and then I will make some BLTs for their troubles. Even then if I had to buy 4 more 240 watt LED panels to cover my grow area, all the above problems would be a factor anyhow. I wonder if there would even be much of a difference at that point.

I the end this project is an experiment and I do feel like I have some good results. So I will try HPS and MH to see the results and as always let you know what happens.

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  #2  
Old 04-02-2011, 07:08 PM
GpsFrontier GpsFrontier is offline
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Quote:
The 1 240 watt LED 7 band panel only seem to cover a 1 foot by 2 foot square and once the plants got to 18 inchs high they started to die off near the bottoms. This thing will grow but I would need quite a few to work for what I want. If they did work as advertised this could have been a different story.
Hello cable24601,
Sadly this is the same exact type of comment I hear from just about everybody that try's LED lighting time and time again. For small low light requirement plants like lettuce there is some potential, but for growing anything substantial and/or a descent quantity of plants they just don't work as the manufactures advertise them to. The reality being that by the time you get enough LED panels to grow what you want, your simply better off using MH and HPS. That's why I always say LED's just aren't ready for prime time yet.

Even if you bought 4 of those 240 watt LED's, you still wouldn't be able to grow a tall plant, unless you placed them around the plant at different heights, and you would still be using almost 1000 watts of electricity. A watt is a watt no matter if it's a LED or MH light, it still costs the same. You would get much better coverage, light penetration, and growth by using 2, 400 watt MH or HPS lights, and only be using 800 watts of electricity.

Sure you will need some ducting, and couple of fans for ventilating the heat generated by the HID lighting. But ducting is not very expensive at Lowe's, and/or Home Depot. And you don't need expensive inline fans from the hydro store either. Even one $40-$60 dollar blower fan can circulate enough cubic feet per minute (cfm), to exchange the entire volume of air in a 20 by 10 foot greenhouse (200 square feet), that was 10 feet tall (200x10=2000 cubic feet). A blower fan with a 2000 cfm would be plenty for that space. The ducting would just help to pull the air from near the lights, or top of the room first (the warmest air). But a $15-$20 bathroom ventilation fan can be placed inline at the end of ducting coming from each light, and should have plenty of cfm to circulate enough air as well.

I'm just guessing here, but I guess the 240 watt LED's cost about $300 each. Probably about the same for a 400 watt MH and ballast. So that basically cuts the cost of equipment in half (buying 2 MH, instead of 4 LED's), and uses less wattage to boot. As well as MH and HPS provide much better coverage, light penetration, and thus plant growth. Of coarse you need to add the wattage for the ventilation to the mix, but I think that's a wash. Simply because either way you'll want/need enough ventilation, or the plants will use up all the co2 in the room then stop growing. By circulating fresh air in the room, you replace the used co2, so you need good ventilation either way.
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Old 04-02-2011, 09:19 PM
Twilly Twilly is offline
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Just throwing this out again, But check out Craigslist for used MH high bay HID lighting.... I got 2 for $50... Still going strong and if you want HPS you can get a conversion bulb
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Old 04-03-2011, 04:26 PM
hydrophotobio hydrophotobio is offline
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I'm willing to bet the 240w isn't a 240w at all. You might have 240w worth of diodes but not in power drivers.
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Old 04-04-2011, 12:00 AM
CAPT38 CAPT38 is offline
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Default low cost lghting

Hey cable,
If you are looking for low cost lightning lowes sells a 85 watt cfl that's equivalent to a 300 watt incandescent for around. 16 bucks, I bought two of them with two brooding lights in all I spent 60 bucks, I was using 25 watt cfls ( my plant growth seemed to slow at the 6th week)
After I set up the new cfls, my plants growth exploded, but the do get some natural sun light throughout the day. I have transfered all my tomato and pepper plants outside into a wicking system and started new seedlings inside, I haven't seen how their doing under the larger cfls. ( @ work ) , but the wife says they are growing pretty good........from what ive read you are going to need a mh and hps one. For veg one for flowering...but don't take my word on that, ( my toms flowered under the cfls I didn't get alot of flowers but my grow room has a window and the plants get some sun light. As far as I am concerned the 300 watt cfls work very well and are a low cost alternative to to mh hps and led and tube fluorescent fixtures. ( I'm not saying that they work better just cheaper over all ) as a beginner in hydroponics I have had very good success with my home built system, admittedly I was somewhat skeptical about hydroponics in the beginning.
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Old 04-08-2011, 03:09 PM
cable24601 cable24601 is offline
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Default So here is what I went with

I just got my new grow lights in the mail yesterday and so far I think I made the right choice. I got a 600 watt digital ballast, fixture, high pressure sodium and metal halide bulb on ebay for $200. After putting this thing together I notice right away that amount of light was far greater than what I had with the LED system. I also noted that the coverage area was about 5 times grater than before. I had to install some ducting to help with cooling as the light was much hotter than what I had in the past and after moving the air pump to the outside of the tent I am only 1 degree hotter then before. The move to the new lighting has given me the option to really start expanding with more plants so I know that I will be busy in the next few weeks adding more hydroponics systems to the grow tent and may even finally see some tomatoes.
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