Growing differences between HPS and LED?

[LabPong]

I am getting ready to setup some HLG lights in my 4x8 tent. Been vegging now for a few weeks and would like to get the LED's setup before I flip to flower.

Are there any big differences in the way I feed or grow my plants going from HPS to LED?

Someone mentioned possibly using cal/mag? I am growing in soil and using FF trio with bloom/budding crystals at low levels. Also tape water use.

Thanks for any help.

 

[Nabbers]

I've done both. My girls like Cali Magic regardless of the light source. Without the cal, I get issues with N uptake. For me the bigger change was struggling to get the heat out with HP'S vs trying not to pull too much out with the LED's. They like it a little warmer in the tent than my ambient house air temps. The heat difference has effected how quickly the pots dry out, and that + pulling the air out slower has upped the humidity.

 

[Renfro]

Let the plants tell you what they want. A calmag product will likely be required.

 

[hotrodharley]

The calcium issues with some LED lights seems to have more to do with potassium availability and uptake. There’s a couple of long threads about it.

 

[LabPong]

I've done both. My girls like Cali Magic regardless of the light source. Without the cal, I get issues with N uptake. For me the bigger change was struggling to get the heat out with HP'S vs trying not to pull too much out with the LED's. They like it a little warmer in the tent than my ambient house air temps. The heat difference has effected how quickly the pots dry out, and that + pulling the air out slower has upped the humidity.

Yes...exactly what I am finding now. We had some really high humidity lately here in MI.....my basement is holding it in now..lol

Using a small ceramic cube heater in my grow room where my tent is...so far this is helping a lot with maintaining temps and humidity in the tent with the LCD's.

It is nice not having so many things in the way inside the tent with the Quantum board lights. And yea....holy crap the girls drink fluids fast now!

I shall go and get some form of cal/mag today....do I just add it in my normal feeding elements? Using FF trio and a few other minor things like Super Thrive, Kelp, the 3 crystals from FF for flowering, and some Budda Bloom.

Now using mainly water and every other 2 feeds with light Big Grow - Tiger B with Thrive and Kelp now for getting through the veg.


My other question is about light height with quantum boards.....Veg vs Flowering?

 

[nevergoodenuf]

instead of a heater, use a dehumidifier for your heat.

 

[LabPong]

instead of a heater, use a dehumidifier for your heat.

Thanks...good point as I need to have a dehumidifier in the grow room now anyways.

 

[LabPong]

Getting back now after getting things sorted out in my tent.

Dehumidifier was a plus plus......tent temps are perfect and I do not have to adjust any incoming or outgoing air to help regulate temps now. Humidity is perfect as I am in a MI basement and humidity is a big issue.

 

[diggs99]

Hps growers try to keep temps down below 80 unless your running co2

led growers try to keep temps up around 85+

That's the main difference I've read about as far as I can tell

 

[LabPong]

Plus the need for cal/mag with no NPK's.

 

[LabPong]

Things seem to be going pretty well not into my 3rd week of flowering.

One thing I am still undecided on is light height of canopy for the flowering stage. Is the 24 inch rule pretty much close? Or can I lower to 18-20 with no problems?

Because of the limited amount of girls...and their high quality genetics...I do not want to hurt this current grow with light height testing.

What are some of the heights you all have been using with no problems?

 

[Aqua Man]

Download a free light meter app. I'm in flower with 85000 lumens at the moment but you need to slowly work up to it or you will get light bleeching. I am also running co2. Anything 45000+ will do for flower but more light is optimal.

The height isn't much of an issue because LEDs give off less heat. What you want is a height that gives you as much uniform light coverage as possible. You can use the light meter to test this out.

Also with your LEDs they have no IR so get yourself a cheap $15 IR thermometer to measure leaf temps and shoot for 75F some people need mid 80'sF I need 80-81 to get my leaf temps there. It will depend on how much your plants are respiring and fan placement etc.

I also use tap water that contains calcium and magnesium and I still require 1ml/gal of calimagic but your growing conditions will be different. Non the less 1ml per gal of calimagic is a safe bet.

Hope that helps

 

[LabPong]

Good info...I have a IR temp meter and just downloaded a light app.

Appreciate your help!


EDIT:
After watering....I had to adjust lights a bit and then used my IR temp gauge. I am ranging between 76-80F for 2 different canopies under 2 of the 320 HLG's.

I have to get the app thing sorted out now....


EDIT:
Now the lux app says I am between 54000 and 65000 lumes.

What is a good range for when you are in veg? I was not sure and just used the 50% on the dimmer nob for veg.

 

[Aqua Man]

Good info...I have a IR temp meter and just downloaded a light app.

Appreciate your help!


EDIT:
After watering....I had to adjust lights a bit and then used my IR temp gauge. I am ranging between 76-80F for 2 different canopies under 2 of the 320 HLG's.

I have to get the app thing sorted out now....


EDIT:
Now the lux app says I am between 54000 and 65000 lumes.

What is a good range for when you are in veg? I was not sure and just used the 50% on the dimmer nob for veg.

Usually up to about 45-50000 but at seedling I go about 10000 and increase to about 45000 by my last week of veg. Then start bumping it up again in flower until I'm about 80000-90000.

I don't veg to long so if you veg longer you can go higher in veg. From seed I go about 5-6 weeks and from clone about 3 weeks

 

[LabPong]

Ok....now I have a question about what humidity level should I be shooting for. I am into my 4th week of flowering now. Im in MI so the humidity is hard and constant now....not sure what I should set the de-humidifier at. Currently RH has been between 55 and 60. Should I try to keep it down to 50?

My temps in lights on time are average of 83-86F .....then about 75F at lights out time.

 

[1212ham]

Download a free light meter app. I'm in flower with 85000 lumens at the moment but you need to slowly work up to it or you will get light bleeching. I am also running co2. Anything 45000+ will do for flower but more light is optimal.

The height isn't much of an issue because LEDs give off less heat. What you want is a height that gives you as much uniform light coverage as possible. You can use the light meter to test this out.

Also with your LEDs they have no IR so get yourself a cheap $15 IR thermometer to measure leaf temps and shoot for 75F some people need mid 80'sF I need 80-81 to get my leaf temps there. It will depend on how much your plants are respiring and fan placement etc.

I also use tap water that contains calcium and magnesium and I still require 1ml/gal of calimagic but your growing conditions will be different. Non the less 1ml per gal of calimagic is a safe bet.

Hope that helps

Those apps aren't very accurate, a $15 lux meter much is better.

 

[Budnarly]

I started with LEDS and figured out with my 3rd grow now that the girls eat cal/mag like candy.

 

[Aqua Man]

Those apps aren't very accurate, a $15 lux meter much is better.

It's only meant to ballpark it doesn't need to be very accurate. It's free and gives a new grower a rough idea.

I do agree with you though

 

[Aqua Man]

Ok....now I have a question about what humidity level should I be shooting for. I am into my 4th week of flowering now. Im in MI so the humidity is hard and constant now....not sure what I should set the de-humidifier at. Currently RH has been between 55 and 60. Should I try to keep it down to 50?

My temps in lights on time are average of 83-86F .....then about 75F at lights out time.

I would try to keep it down

 

[LabPong]

Ok...now almost 2 days since I lowered the humidity levels to just above 50......seems like it is a positive change with how the girls are responding so far.

Also, I have noticed they like constant amounts of cal/mag as well it seems. I use the non-NPK version and give them about 1tsp/gal every water/feed...so daily as they suck up fluids fast.

I did notice prior to using the cal/mag just before and after the flip...the plants were much lighter in color and tended to droop easily. Not sure if that was because of too low temps or too high humidity at the time during veg as well.

So my question is how much cal/mag is too much? Are there quick signs of problems if you over do it on the C/M?

Thanks again for your help!