Upgrading flowering light to LED

GreenForMiles

GreenForMiles

Active Member
Hello, I started off growing with a 600 watt Metal Halide for veg and 600 watt HPS for flowering. Just recently I upgraded my 600 watt Metal Halide to 3 QB96's. The difference in growth othe lower branching was phenomenal under the LED compared to the MH. The Metal Halide I was using was marked as 55,000 Lumens and my flowering HPS bulb is 85,000. I only have about a foot worth of space between my light and plants, so im wondering if these leds could replace 85k lumen bulb and not light burn from 12 inches away?

I found this link that gives an estimate of lumens per QB - https://www.aeroponicgrowers.com/calculators?
Would I be okay using 3 a foot away from my plants? https://horticulturelightinggroup.com/products/qb288-v2-with-slate-2-triple?_pos=3&_sid=54eaadcdc&_ss=r
Or would I need to be replacing the HPS with something less intense like 2 QB288's (https://horticulturelightinggroup.com/products/qb288-v2-rspec-slate-2-double-combo-1)? Thanks in advance-
 
ҖҗlegilizeitҗҖ

ҖҗlegilizeitҗҖ

Well-Known Member
GreenForMiles said:
Hello, I started off growing with a 600 watt Metal Halide for veg and 600 watt HPS for flowering. Just recently I upgraded my 600 watt Metal Halide to 3 QB96's. The difference in growth othe lower branching was phenomenal under the LED compared to the MH. The Metal Halide I was using was marked as 55,000 Lumens and my flowering HPS bulb is 85,000. I only have about a foot worth of space between my light and plants, so im wondering if these leds could replace 85k lumen bulb and not light burn from 12 inches away?

I found this link that gives an estimate of lumens per QB - https://www.aeroponicgrowers.com/calculators?
Would I be okay using 3 a foot away from my plants? https://horticulturelightinggroup.com/products/qb288-v2-with-slate-2-triple?_pos=3&_sid=54eaadcdc&_ss=r
Or would I need to be replacing the HPS with something less intense like 2 QB288's (https://horticulturelightinggroup.com/products/qb288-v2-rspec-slate-2-double-combo-1)? Thanks in advance-
Click to expand...
How large of space do you have? How tall is it? What is your growing medium? What is your budget?
Most LEDS can be used from veg to flower
 
LEDTonic - Daniel

LEDTonic - Daniel

Active Member
I think it would be a good idea for you to familiarize yourself with the term PPFD - Photosynthetic Photon Flux Density.
PPFD is essentially another word for light intensity. PPFD can be measured in unit µmol/m2/s. We know that mature cannabis plants do well with PPFD levels of 600-900 µmol/m2/s. If all other factors like nutrients, temperature, humidity, etc are met, plants can even take a bit higher PPFD levels.

There are so called quantum sensors that measure PPFD but they are rather expensive. The good ones are $500+. Lux meters, very inexpensive, are a good alternative. Lux and lumen are somewhat related. Lumen is a measurement of total light output from a lamp whereas lux is a spot measurement.

Let's say a lamp emits 55.000 lumens. The emitted light will be projected in all kinds of directions. We want to know how much lands on our plants, i.e. spot measurements. With a lux meter (search lux meter on Amazon to find decent products) you put the sensors on a spot that you want to measure, eg. on your canopy. The meter will present a value, eg 40.000 lux.
Lux can then be converted to PPFD. The conversion is not 100% accurate as the ratio is not clearly defined and each lux meter has a different sensitivity, but you should still get a ballpark reading.

Once you know what lux your plants receive, take a look here: https://www.apogeeinstruments.com/conversion-ppfd-to-lux.
There are charts and tables that help you convert your lux value to PPFD.

If you're above 1000 PPFD you're most likely burning your plants. If you're below 500, your plants could do with more light.
Speculating how high PPFD several different lamps combined emit is difficult and any results will be highly inaccurate.

Hope this helps!
 
GreenForMiles

GreenForMiles

Active Member
LEDTonic - Daniel said:
I think it would be a good idea for you to familiarize yourself with the term PPFD - Photosynthetic Photon Flux Density.
PPFD is essentially another word for light intensity. PPFD can be measured in unit µmol/m2/s. We know that mature cannabis plants do well with PPFD levels of 600-900 µmol/m2/s. If all other factors like nutrients, temperature, humidity, etc are met, plants can even take a bit higher PPFD levels.

There are so called quantum sensors that measure PPFD but they are rather expensive. The good ones are $500+. Lux meters, very inexpensive, are a good alternative. Lux and lumen are somewhat related. Lumen is a measurement of total light output from a lamp whereas lux is a spot measurement.

Let's say a lamp emits 55.000 lumens. The emitted light will be projected in all kinds of directions. We want to know how much lands on our plants, i.e. spot measurements. With a lux meter (search lux meter on Amazon to find decent products) you put the sensors on a spot that you want to measure, eg. on your canopy. The meter will present a value, eg 40.000 lux.
Lux can then be converted to PPFD. The conversion is not 100% accurate as the ratio is not clearly defined and each lux meter has a different sensitivity, but you should still get a ballpark reading.

Once you know what lux your plants receive, take a look here: https://www.apogeeinstruments.com/conversion-ppfd-to-lux.
There are charts and tables that help you convert your lux value to PPFD.

If you're above 1000 PPFD you're most likely burning your plants. If you're below 500, your plants could do with more light.
Speculating how high PPFD several different lamps combined emit is difficult and any results will be highly inaccurate.

Hope this helps!
Click to expand...
Thank you, I appreciate the explanation as I did find this chart -

LIGHT INTENSITY REQUIREMENTS

Seedlings, Clones Under 100 PPFD

Veg, Greens 150 PPFD - 400 PPFD

Extended Veg with healthy plants 350 PPFD to 500 PPFD

Flowering, Fruits 400 PPFD to 800 PPFD

Flowering with Supplement CO2 600 PPFD to 1100 PPFD

*Chart is for reference only. Plant response may vary due to plant types and environmental conditions.


As for budget, anything less than 500$. I grow in coco coir 5 gallon pots, typically my plants are about 2.5 - 3 feet before being put to flower. The 3 QB96's are putting out a ton of light, I have a lux reader for them and I'm very happy with them. My flowering grow space is about 3x5, sometimes I have to train them to fit if they're too tall.
 
bernie344

bernie344

Well-Known Member
GreenForMiles said:
Hello, I started off growing with a 600 watt Metal Halide for veg and 600 watt HPS for flowering. Just recently I upgraded my 600 watt Metal Halide to 3 QB96's. The difference in growth othe lower branching was phenomenal under the LED compared to the MH. The Metal Halide I was using was marked as 55,000 Lumens and my flowering HPS bulb is 85,000. I only have about a foot worth of space between my light and plants, so im wondering if these leds could replace 85k lumen bulb and not light burn from 12 inches away?

I found this link that gives an estimate of lumens per QB - https://www.aeroponicgrowers.com/calculators?
Would I be okay using 3 a foot away from my plants? https://horticulturelightinggroup.com/products/qb288-v2-with-slate-2-triple?_pos=3&_sid=54eaadcdc&_ss=r
Or would I need to be replacing the HPS with something less intense like 2 QB288's (https://horticulturelightinggroup.com/products/qb288-v2-rspec-slate-2-double-combo-1)? Thanks in advance-
Click to expand...
I ran my 480w QB @ 12inch in early flower by week 4 of flower the hairs were mostly brown with small amount of new growth.
After raising light to 22in @80% after 3 weeks my plant now has 90% white hairs and growing strong.
 
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