# LED dimmable lighting and watts

• None

#### Palgravefarmer

Hi All,

Being a newbie to LED lighting with the dimmable function, I have a dumb question albeit an important one:

If (to the wall) I have a LED light at 100% power of 700 watts, should I dim it to 50%, would that mean I am now running 350 watts instead of the 700W?

Also, if I have an overkill LED light in a 4x4, can I run from seed to harvest at 50% dimmable should it meet the ppfd requirements?

#### coherent

When you adjust the dimmer on an LED light, your power usage goes up or down directly proportional to the wattage you've selected. To put it simply, if you dim your LED lights 50% they use about 50% as much energy! So, if your light is overkill, you would save money lowering the light and dimming it vs raising it and increasing brightness as long as your coverage is still sufficient.

#### gorillaglueaaron

##### đź¦Ť
Supporter
Hi All,

Being a newbie to LED lighting with the dimmable function, I have a dumb question albeit an important one:

If (to the wall) I have a LED light at 100% power of 700 watts, should I dim it to 50%, would that mean I am now running 350 watts instead of the 700W?

Also, if I have an overkill LED light in a 4x4, can I run from seed to harvest at 50% dimmable should it meet the ppfd requirements?

Depends on the potentiometer that's being used. Most that are used for LEDs are linear but some are quadratic. Short answer most likely 700w at 50% is 350w.

Second question, I don't know which light it is so I can't really help you with that.

#### gorillaglueaaron

##### đź¦Ť
Supporter
When you adjust the dimmer on an LED light, your power usage goes up or down directly proportional to the wattage you've selected. To put it simply, if you dim your LED lights 50% they use about 50% as much energy! So, if your light is overkill, you would save money lowering the light and dimming it vs raising it and increasing brightness as long as your coverage is still sufficient.
That's a good point. The higher you raise the light, the better the coverage is so you can decide whether you want better intensity or lower electricity cost.

#### Dub_City405

Run the light how you want. I suggest 100 percent in flower. I suggest no lower than 50% during seedling and veg. Id really go to 100 week 2 of veg. I want 4 to 5 ft plants. Bigger weight.

#### growsince79

Run the light how you want. I suggest 100 percent in flower. I suggest no lower than 50% during seedling and veg. Id really go to 100 week 2 of veg. I want 4 to 5 ft plants. Bigger weight.
I've found 5 foot plants indoors are a waste of time and money. Why grow em that extra month just to cut the worthless bottom 2-3 feet off? My best relative yields comes from fairly short plants with 3-4 week veg.

#### gorillaglueaaron

##### đź¦Ť
Supporter
I've found 5 foot plants indoors are a waste of time and money. Why grow em that extra month just to cut the worthless bottom 2-3 feet off? My best relative yields comes from fairly short plants with 3-4 week veg.
Do you find quality even slightly worse with smaller plants?

#### Dub_City405

I only veg for 3 weeks then flower for 8 weeks. Water 9th week and cut and dry. Idk if a harvest every 12 weeks is bad or not.?

#### gorillaglueaaron

##### đź¦Ť
Supporter
I only veg for 3 weeks then flower for 8 weeks. Water 9th week and cut and dry. Idk if a harvest every 12 weeks is bad or not.?
Just depends on your grow style.

#### growsince79

I only veg for 3 weeks then flower for 8 weeks. Water 9th week and cut and dry. Idk if a harvest every 12 weeks is bad or not.?
5 feet tall with a 3 week veg from seed sprout? What strain was that?

#### PK1

Supporter
I only veg for 3 weeks then flower for 8 weeks. Water 9th week and cut and dry. Idk if a harvest every 12 weeks is bad or not.?
what do you yield? and i take thats photos only?>

#### Dub_City405

Why would i use seeds if i got clones? Only youre talking about seeds

#### growsince79

Well that makes more sense. How tall are they when you flip to 12-12?

#### Dub_City405

Lol its the only sense when im talking about that quick flip time. Usually 2 ft. Or 3

#### growsince79

Lol its the only sense when im talking about that quick flip time. Usually 2 ft. Or 3
Have you tried flipping sooner like a sea of green. 3-4 clones/sqft - 1 week veg? No wasted time or vertical space. Probably get a better relative yield and easier trimming.

#### Aqua Man

This again is an example of different grows and experiences being over simplified and that can lead to issues. If you want to take the simple route then that's what ya get. No different than say teaching math... you ask whats 2+2 I tell you 4 it does you no good when you want to know what 5+5 is. If you learn addition then you can answer yourself in all scenarios

First advice is to read your plants and learn the symptoms of too much light. This will change in every single grow room, each strain and has many contributing factors. So IMO you cannot just go with arbitrary 50% 75% 100% numbers.

DLI (daily light integral) is where you want to start and things will start making more sense. DLI is simply the amount of photons (light energy) a plant receives over a period of..... a day. It clear when you have a longer light period you need less light to achieve the same value than with a shorter light period like photos in flower.

Going against my own advice and giving a simple answer is if you are running 18/6 and change to 12/12 you will need to increase the intensity by 1/3 in order to get the plant the same amount of light per day. This is why in flower we need more light.

Another eg. Is 24/0 light to 12/12 you need to double the amount of light. But 24/0 would require less light than 18/6.

You also need to take into account the photosynthetic rates because plants can only use so much light at a time. This is where you need to learn the symptoms of too much light.

If you want I can dig up some articles but you can simply google DLI cannabis and light stress symptoms cannabis and ask questions that arise from your reading.

The hardest part of learning is not knowing what you dont know. So there are 2 things you can take time to learn about to help answer your own question and understand in the future how you may want to adjust your intensity and photoperiod.

If you have questions on it just post back but nobody can learn it for you and it's no good having an answer if you don't understand it.

#### Dothraki

This again is an example of different grows and experiences being over simplified and that can lead to issues. If you want to take the simple route then that's what ya get. No different than say teaching math... you ask whats 2+2 I tell you 4 it does you no good when you want to know what 5+5 is. If you learn addition then you can answer yourself in all scenarios

First advice is to read your plants and learn the symptoms of too much light. This will change in every single grow room, each strain and has many contributing factors. So IMO you cannot just go with arbitrary 50% 75% 100% numbers.

DLI (daily light integral) is where you want to start and things will start making more sense. DLI is simply the amount of photons (light energy) a plant receives over a period of..... a day. It clear when you have a longer light period you need less light to achieve the same value than with a shorter light period like photos in flower.

Going against my own advice and giving a simple answer is if you are running 18/6 and change to 12/12 you will need to increase the intensity by 1/3 in order to get the plant the same amount of light per day. This is why in flower we need more light.

Another eg. Is 24/0 light to 12/12 you need to double the amount of light. But 24/0 would require less light than 18/6.

You also need to take into account the photosynthetic rates because plants can only use so much light at a time. This is where you need to learn the symptoms of too much light.

If you want I can dig up some articles but you can simply google DLI cannabis and light stress symptoms cannabis and ask questions that arise from your reading.

The hardest part of learning is not knowing what you dont know. So there are 2 things you can take time to learn about to help answer your own question and understand in the future how you may want to adjust your intensity and photoperiod.

If you have questions on it just post back but nobody can learn it for you and it's no good having an answer if you don't understand it.