300W LED for single plant or 210W?

[Oful33]

Hello people.

I am thinking to grow one plant in a small 50x50x100cm tent, with one fan, 6l air pot, nutriets etc. However I am not quite sure should I go for 300w or 210w LED. Obviously 300w seems like it would produce more bud, but its operating temperature is 20-50C, whilst 210W is 32-43C. It appears that 300w might heat up worse, therefore as I will be running just one fan and tent is pretty small it might get too hot. I am pretty confused here so any opinion is appreciated

 

[TWINTURBODOGO]

The more the better. We have 2 300w led fixtures for one plant in a 2'x4'x5' tent

We use a 6" exhaust fan on a speed controller and our temps are mid 70's to low 80's.

 

[Bud Good]

Heat and temperature are two separate things. A butane micro torch has a much higher temperature than a bonfire with 50 wooden pallets on it, but 50 pallets are going to put off more heat. Operating temperature is generally the temperature at which a device can be operated, not the temperature it will reach.

Plenty of people use 300 true-watt lights in tents your size, that 300w LED is probably more like 100 actual watts. I don't think the 300w equivalent will be a problem. I have a 1000w equivalent LED light in a space roughly 2'x3'x8' and just an 80 CFM bathroom exhaust fan keeping it cool. Highest temp at the fan at the very top of the closet was 93°F and that was with the incoming air pretty close to 85°F.

 

[masonman]

Whats more important, is what will be the temperature of the intake air, and how fast can you vent the heat.
The cooler the intake air, and the higher the CFM of your exhaust fan, the more watts you can use in your tent.

You remember this in school? Matter or energy cannot be destroyed, only converted?

The electricity that is used inside a grow area is eventually converted to heat. When dealing with cooling, think "watts of heat"

100cm is an extremely short tent. Not well suited for flowering.

Find the smallest (skinniest) 4" carbon filter/fan combo. Stand the filter up in a corner of the tent. Attach flexible 4"duct to it, then run the duct out of the tent from one of the 4" openings. Attach the 4" fan to duct on the outside of the tent for exhaust.

If you do this, I'm sure you will be able to run the 300 watt light (I'm assuming the light only draws about 140 watts from the wall)

If smell isn't an issue, skip the carbon filter...

Anymore questions, feel free to ask away... There may be other options. Tell us everything you can about what you have to work with.

 

[Oful33]

Thank you for replys. I will be using one fan only, it comes with 4" carbon filter and is used to blow air out of the tent, there will ne no more fans. None blowing directly into the plant, none blowing air inside the tent. So even so, a 300w light wont cause overheating issues as real output is likely to be 100-140w? Correct me if I am wrong.

I have one small silly query. Any ideas what the yield might be? Its autoflower feminised fast bud #2 by sweet seeds. I will be using magic gro fert for veg (not sure if correct name, but I am sure you know which one I am ferrering to), foxfarm tiger bloom for flowering. Bat mix as a soil with some added perilite. In 6l air pot. I would love to hear your opinions about the yield, i will proboably open an journal afterwards to keep you updated anyway.

 

[Bud Good]

Thank you for replys. I will be using one fan only, it comes with 4" carbon filter and is used to blow air out of the tent, there will ne no more fans. None blowing directly into the plant, none blowing air inside the tent. So even so, a 300w light wont cause overheating issues as real output is likely to be 100-140w? Correct me if I am wrong.

I have one small silly query. Any ideas what the yield might be? Its autoflower feminised fast bud #2 by sweet seeds. I will be using magic gro fert for veg (not sure if correct name, but I am sure you know which one I am ferrering to), foxfarm tiger bloom for flowering. Bat mix as a soil with some added perilite. In 6l air pot. I would love to hear your opinions about the yield, i will proboably open an journal afterwards to keep you updated anyway.

You will want a small fan blowing across the plant. In veg it helps to strengthen the stems, in both veg and flower it keeps the leaves from touching each other in the same spot and will reduce your chance of mold. Where two leaves continue to touch, you will see condensed water. LEDs use *roughly* 1/3 the power of other lights - partly because they're more efficient, partly because they only produce the wavelengths that the plants actually use. So yeah, 100-140 watts is a safe guess for the "300 watt" LED.

I believe you will need another fertilizer for flower, I'm about 99% sure the NPK ratio of Tiger Bloom is less than ideal for our plants. There is another Fox Farms set of granulated fertilizers (Cha Ching, Beastie Bloomz, Open Sesame) with numbers around 0-50-10. Check out this thread Nutes - What To Use & How To Use Them - Tutorial

Hard to guess yield, maybe a pro can give you something close. 1g/watt is considered very good, with noobs like us being closer to .5g/watt if we're lucky.

 

[Oful33]

Im quite short of space (50x50x100cm tent), cant really find any small fan that is not an usb one. Any suggestions?

 

[OregonGrown79]

That a pretty small grow space, but it can be done!! I am in a 2footx2footx5foot grow tent. I am using a Mars 2 400 watt LED. I am not running an extraction fan and I see high temperatures in the 80-82 degree range. I have 1 small 6 inch fan clipped on the supports blowing down across my plants and 1 larger 8 inch (very thin) fan at the bottom circulating and pulling in freshape air from a vent. Seems to work well for me. If you look you can see my fan set up.

OG79

 

[Oful33]

Looks like it's working well for you, nice growth! I guess I'll have to get that fan than, it's for sake of my girls.

 

[TorturedSoul]

50 cm is only 19.685 inches, so you're growing in a space that is approximately 2.7 square feet. Last I heard, the recommendation for LED lighting was anywhere from 25 to 55 watts per square foot; a range is given due to the extreme difference between the best and the worst LED grow panels, lol. Following that recommendation, you'd want to shoot for somewhere between 67.5 and 148.5 watts of lighting. And that's actual watts, not bullsh!t advertiser pretend "watts." A couple of COBs, each drawing 50 watts, might be more than adequate. We have a sponsor that sells such things in kit form, which would save you some money over buying an already assembled product. Or, if you're looking at one of the... value-class (cheaper) LED panels, maybe aim for the higher end of that range and get one that draws 148 to 150 watts.

Basically, you should probably be trying to attain 1,000 μmol/m²/second (and probably not over 1,500 μmol/m²/second). I'll let you do the math on that one (for your space) and get the data from whoever you are thinking about purchasing an LED product from. Some of them put such things right on their website, but with other companies, it's like pulling teeth to get actual pertinent data.

 

[EARTHWALKER]

For reference, my tent is 80x80x160, I grow one plant and use a 48x3 led. Temps around 78-82 on a normal day and up to 86 on a scorching day with no inwards venting; only outwards.

With regards to a fan, I did have a 400w hps and had to vent cold air inwards so I used an old 8inch 9v computer case fan attached to a spliced 9v mobile phone charger. Worked a treat.