Seedling and wattage question? LED

[Skylander]

Is there a formula I can use to get the proper light distance for my seedlings? I have 3 seedlings ranging from one inches to almost three inches tall due to stretching I think. I lowered my lights to about four feet away and hopefully that helps me out. I just don't want to kill my plants!

 

[tommy217xxx]

How many sets of internodes are there? i have a 3" seedling with 4 sets of nodes and My t5 is a foot away. Just make sure they dont dry out.

 

[Adjorr]

2 feet is a good distance for LED and seedlings, you will want your LED 1-2 feet away throughout your grow

 

[Skylander]

I have 4 nodes! I keep my medium moist to the touch but dry enough to keep air available.

 

[Skylander]

Did you do that with the widows youre growing? Just curious!

 

[Adjorr]

yup my clones were planted with the lights 2 feet above them and I wont move the lights unless they grow to within 8 inches or so of the light, ive been using training techniques to keep them short and bushy

 

[Skylander]

Ok I think Ill drop them down to about 2 1/2ft and see how they react. I have a oscillating fan in my tent and they seem to be strong enough to take the breeze and stand on there own so I think that will bring me in the right direction.

 

[Adjorr]

yup that should solve your problems, 4 feet is way to far for an led, what wattage light do you have, how many plants and how big is ur space?

 

[Skylander]

I have two 750 watt leds and 4 to eight plants in a 5x9 tent raised to close to 8ft in height.

 

[Ogracious]

Isn't the formula "if it's too hot for your hand, it's too close"? That is what I have used and it works great for me. I give it a couple inches of buffer room beyond that or further depending on how often I am able to check on it/water it. Underwatered plants are much more susceptible to burn.

-Sap

 

[Adjorr]

Isn't the formula "if it's too hot for your hand, it's too close"? That is what I have used and it works great for me. I give it a couple inches of buffer room beyond that or further depending on how often I am able to check on it/water it. Underwatered plants are much more susceptible to burn.

-Sap

yeah that's the rule for HID light types. LED run a lot cooler and exhaust their heat upwards away from the plant, you could have an led light touching the plants and it would not burn. However since LED lights have specific beam angels and individual bulbs to make up a full spectrum they need enough distance for the lights to blend together and for the canopy to be exposed to all the individual diodes. 1-2 feet is the recommended distance for optimal LED coverage. A larger unit like a 750 might need to go to 3 feet to cover a wider area. One of the draw backs to LED is that they only cover a small footprint below the light, the higher your light is the bigger the footprint can be but the less intense the light is. This is why I and many other believe in using multiple LEDs such as 240 or 300 w panels to cover larger areas, this way you get more even light distribution over the canopy. LEDs grow the best when the plants are as close to being directly underneath the lights as possible. I have 600w in my setup but its split over 3 panels in a 2x3 space

 

[Ogracious]

yeah that's the rule for HID light types. LED run a lot cooler and exhaust their heat upwards away from the plant, you could have an led light touching the plants and it would not burn. However since LED lights have specific beam angels and individual bulbs to make up a full spectrum they need enough distance for the lights to blend together and for the canopy to be exposed to all the individual diodes. 1-2 feet is the recommended distance for optimal LED coverage. A larger unit like a 750 might need to go to 3 feet to cover a wider area. One of the draw backs to LED is that they only cover a small footprint below the light, the higher your light is the bigger the footprint can be but the less intense the light is. This is why I and many other believe in using multiple LEDs such as 240 or 300 w panels to cover larger areas, this way you get more even light distribution over the canopy. LEDs grow the best when the plants are as close to being directly underneath the lights as possible. I have 600w in my setup but its split over 3 panels in a 2x3 space

Cool, thanks for the lesson! Any idea on why they group LEDs of the same spectrum together instead of setting it up more like RGB (have one of each color next to the other in a tiled format)? Seems it would allow you to bring the panel closer to your plants.

-Sap

 

[Skylander]

My veg footprint is 7ft per light and flower is 4.5ft. Both lights are the same and are full spectrum lights. With my two 750 watt led I have no uncovered spots for flower or veg in a 5x9 tent.

 

[Trousers]

I am a LED n00b, just started 3 Dutch Passion Blueberry seeds to make a feminized seed crop. 300 watt LED from ebay.
I have the light about 1' 8" away and my plants seem great.

Listen to adjorr, he is the one that convinced me to try a cheapo LED. It is working very well so far. My plants look great.
I have much more light than with my 250 watt hps and it is about the same temp, maybe a bit cooler.

 

[Skylander]

Oh..... don't get me wrong I not saying he is wrong by no means. I was just saying with two BD 750s and a 5x9 tent I have no need for more light as far as light and space is concerned. Check them out on the blackdog website.

 

[Adjorr]

My veg footprint is 7ft per light and flower is 4.5ft. Both lights are the same and are full spectrum lights. With my two 750 watt led I have no uncovered spots for flower or veg in a 5x9 tent.

I would still try and keep the lights within 3 feet of the canopy to avoid stretch

 

[Skylander]

That makes sense... I moved them down last night. Seems to be ok so far....no adverse reactions so good deal. Cant wait until it get cold out so I wont have to use my spot cooler!!!!!!!

 

[Skylander]

How long do you think I could veg for in 5gal containers before it gets root bound. I was thinking I would just grow 3 good sized plants. I thought I would be able to do six to eight plants but I don't think that is the route I wanna go...

 

[Adjorr]

In 5 gallon conatiners you don't really need to worry much about becoming root bound, the rule of thumb is 1 gallon per month of growth so 5 gallons gives you a 2 month veg and 3 month flower aproximatly, more then enough for any strain of cannabis. I would put 4 plants under each of your 2 lights, that's what id do