Lighting What wattage do you need

[darknight_420]

Hi all

It's something I dont know the answer to but how do you determine what wattage you need at the different stages.

I've a par+275w dimmable and it's hanging in a 60x90x160 tent and I've a 200w dimmable in a 50x90x160 tent for the autos.

I'm reading something like 50w is optimum per sq for so if ive 6sq ft then I'm guessing that'll be 200w but I'm sensing I'm frying the plant.

I did a test on my 200w before and its been pretty OK but when I checked the watt it was only at 90w so I cranked it up to 140w for 2hrs and tips burning so I've turned it down again, but that then mean it's less than 20w per sq ft.

I'm baffled over it so any pointers to consider would would great.

Thanks

 

[Mañ'O'Green]

Hi all

It's something I dont know the answer to but how do you determine what wattage you need at the different stages.

I've a par+275w dimmable and it's hanging in a 60x90x160 tent and I've a 200w dimmable in a 50x90x160 tent for the autos.

I'm reading something like 50w is optimum per sq for so if ive 6sq ft then I'm guessing that'll be 200w but I'm sensing I'm frying the plant.

I did a test on my 200w before and its been pretty OK but when I checked the watt it was only at 90w so I cranked it up to 140w for 2hrs and tips burning so I've turned it down again, but that then mean it's less than 20w per sq ft.

I'm baffled over it so any pointers to consider would would great.

Thanks

Watts is not a good measure for light on the plant. There are too many variables that effect the efficiency of lights.

If you have an IPhone you can get the Photone app and use PAR and DLI which are the best methods to determine the light on your plants. The Beta version works on Android but you need reliable information from the light MFG to calibrate it.

If DLI is new to you there is a good explanation here:

http://pllight.com/demystifying-light-levels-for-cannabis-grows/

This is a good chart to follow for cannabis

 

[Cannaficionado]

Like mog said, wattage isnt as important as meeting thr needs of the plant. Your looking for a light that meets the needs of the plant at the peak of flowering. His chart is good, when looking at your lights par map that should come with it, make sure its footprint is within your tents range and it should be ok. Most par charts will have a 2x2, 2x4, 3x3, or 4x4 par map depending on the actual size or wattage of the light. Usually they will say suitable for a certain veg or flowering space.

 

[NORBY]

Watts is not a good measure for light on the plant. There are too many variables that effect the efficiency of lights.

If you have an IPhone you can get the Photone app and use PAR and DLI which are the best methods to determine the light on your plants. The Beta version works on Android but you need reliable information from the light MFG to calibrate it.

If DLI is new to you there is a good explanation here:

http://pllight.com/demystifying-light-levels-for-cannabis-grows/

This is a good chart to follow for cannabis

View attachment 1575065

I run my lights 24/7
By doing this does that mean a standard ppfd chart is useless for me as its the DLI that will mater when not having a dark period

 

[Mañ'O'Green]

I run my lights 24/7
By doing this does that mean a standard ppfd chart is useless for me as its the DLI that will mater when not having a dark period

No you are still providing a given amount of PPFD over 24 hours.

Science says a night time is needed by the plants but a lot of growers use 24/0 for various reasons.

 

[darknight_420]

@Mañ'O'Green thanks, now thats something I didn't know

I git this chart when I got the par+ and I was told full whack in a 120x60 tent is fine but I downsized to a 60x90 tent for the closet.

I'm actually of thinking of reshaping a tent and fitting a 75x75 in the closet.

The chart is set for a 80x80 and has all those numbers.

If I was to download an app on the android, am I aiming for the same reading on my phone for the same distance and what are those numbers, I think its par and not ppfd?

I've done 6 grows with this LED and each ones different lol

Thanks

 

[darknight_420]

I think I've sussed it and its just a case of keeping it in the area that says good on my ppfd app, I can see those readings in my chart are the ppdf and after downloading the app im pretty close and just fraction high right in the centre.

I can see me becoming obsessed with this now lol writing the different settings and readings for each plant om growing lol

Thanks for helping me understand its no about the wattage