Autos are different than photos. Most folks run autos on a 18-6 schedule. Due to the increase in time on for your lights you need to adjust light strength.
Lots of people measure in ppfd which is a nice measurement of actual energy per square. I measure in lux which is not as accurate for energy measurement but helps keep me in the lanes.
When you have a photo plant to initiate flowering you reduce schedule to 12 12. When you do this growers increase the lights substantially as the plant has less time to use and store energy and nutrition. Autos ran at 18-6 do not need this huge increase. The key to cannabis lighting is the daily light interval. Without CO2 DLI should increase from about 28 at flower start to 38 by end of flower.
Autos take less saturation light on a longer schedule as the lights are not as high but the same amount of light as a 12-12 schedule

In my photo grow I do 65k lux at the tops which is close to 950 ppfd. Doing autos right now I am at 40k lux at the tops or about 600 ppfd.

Thanks

JIMKSI64 said:

Autos are different than photos. Most folks run autos on a 18-6 schedule. Due to the increase in time on for your lights you need to adjust light strength.
Lots of people measure in ppfd which is a nice measurement of actual energy per square. I measure in lux which is not as accurate for energy measurement but helps keep me in the lanes.
When you have a photo plant to initiate flowering you reduce schedule to 12 12. When you do this growers increase the lights substantially as the plant has less time to use and store energy and nutrition. Autos ran at 18-6 do not need this huge increase. The key to cannabis lighting is the daily light interval. Without CO2 DLI should increase from about 28 at flower start to 38 by end of flower.

Cannabis DLI for Your Full Grow Cycle

If there's one question that never allows a cannabis grower any sleep, it's — are my plants getting enough light? If this question has ever crossed your mind, don't worry, you're not alone. Read along as we describe the lighting requirements of cannabis over the full growth cycle.

growlightmeter.com

Autos take less saturation light on a longer schedule as the lights are not as high but the same amount of light as a 12-12 schedule

In my photo grow I do 65k lux at the tops which is close to 950 ppfd. Doing autos right now I am at 40k lux at the tops or about 600 ppfd.

Click to expand...

thanks!

I’m looking at a spider farmer g4500 320watt light. Are those too much? Just right? Maximum potential for 8sqft?

Where are you getting these light measuring meters? How much are those usually?

JIMKSI64 said:

Autos are different than photos. Most folks run autos on a 18-6 schedule. Due to the increase in time on for your lights you need to adjust light strength.
Lots of people measure in ppfd which is a nice measurement of actual energy per square. I measure in lux which is not as accurate for energy measurement but helps keep me in the lanes.
When you have a photo plant to initiate flowering you reduce schedule to 12 12. When you do this growers increase the lights substantially as the plant has less time to use and store energy and nutrition. Autos ran at 18-6 do not need this huge increase. The key to cannabis lighting is the daily light interval. Without CO2 DLI should increase from about 28 at flower start to 38 by end of flower.

Cannabis DLI for Your Full Grow Cycle

If there's one question that never allows a cannabis grower any sleep, it's — are my plants getting enough light? If this question has ever crossed your mind, don't worry, you're not alone. Read along as we describe the lighting requirements of cannabis over the full growth cycle.

growlightmeter.com

Autos take less saturation light on a longer schedule as the lights are not as high but the same amount of light as a 12-12 schedule

In my photo grow I do 65k lux at the tops which is close to 950 ppfd. Doing autos right now I am at 40k lux at the tops or about 600 ppfd.

Click to expand...

I’m looking at a spider farmer g4500 if that matters……

MJmadscientist said:

I’m looking at a spider farmer g4500 if that matters……

Click to expand...

Are you putting it in a 2x4?
It looks like they are using the budget leds from bridgelux. I couldnt find the exact ones. I think there are some better budget options out there or better leds for the same price.

voltage said:

Are you putting it in a 2x4?
It looks like they are using the budget leds from bridgelux. I couldnt find the exact ones. I think there are some better budget options out there or better leds for the same price.

Click to expand...

It’s the Samsung evo leds

MJmadscientist said:

Thanks

thanks!

I’m looking at a spider farmer g4500 320watt light. Are those too much? Just right? Maximum potential for 8sqft?

Where are you getting these light measuring meters? How much are those usually?

Click to expand...

That light is fine. I have a 400 watt panel at 60% 22 inches from canopy giving me 40k lux. Here is the tool. It has a downloadable app available that recognizes the bt tool and uses a very standard 3500k conversion that's within 5% of the manufacturers par values for my light.
That light will be fine for photos in a 4x2 also.

MJmadscientist said:

It’s the Samsung evo leds

Click to expand...

Yes 2x4 starting out. See if this is a viable option. Outdoors it free light but has its drawbacks. Also it’s seasonal.

MJmadscientist said:

Yes 2x4 starting out. See if this is a viable option. Outdoors it free light but has its drawbacks. Also it’s seasonal.

Click to expand...

Free is the best

JIMKSI64 said:

That light is fine. I have a 400 watt panel at 60% 22 inches from canopy giving me 40k lux. Here is the tool. It has a downloadable app available that recognizes the bt tool and uses a very standard 3500k conversion that's within 5% of the manufacturers par values for my light.

Amazon.com : UNI-T Light Meter UT383BT Lux Meter Lumens Digital Illuminance Meter 0~199900 Lux (0~18500 FC) Foot Candles Luxmeter for Film Photography Plants Photometer Lighting Intensity Brightness Measurement : Electronics

Amazon.com : UNI-T Light Meter UT383BT Lux Meter Lumens Digital Illuminance Meter 0~199900 Lux (0~18500 FC) Foot Candles Luxmeter for Film Photography Plants Photometer Lighting Intensity Brightness Measurement : Electronics

www.amazon.com

That light will be fine for photos in a 4x2 also.

Click to expand...

So more light isn’t a good thing? I wondered why everyone turns them down.

MJmadscientist said:

Yes 2x4 starting out. See if this is a viable option. Outdoors it free light but has its drawbacks. Also it’s seasonal.

Click to expand...

The se series uses evo i have 1. The g series uses the bridgelux.

MJmadscientist said:

So more light isn’t a good thing? I wondered why everyone turns them down.

Click to expand...

More. Less. We need appropriate lights.
When I run photos under 12-12 the lux level will be much higher like 65k. It will be 26 inches from panel as that's the hight I mapped out for a pattern I can deal with. Gives me a spare 150 panel for whatever or have plants at different ages or I have a fail.

MJmadscientist said:

So more light isn’t a good thing? I wondered why everyone turns them down.

Click to expand...

I haven't read every post but from what I have read, it sounds like there's some things about lighting that you're trying to get a better grasp on.

Yes, there really is a "thing" called over-lighting. If you were to start browsing the grow diaries here, you'll see its actually fairly common with a new grower starting out. When it comes to growing top shelf cannabis, your motto should be "Everything in balance. Nothing in excess." You might even see it stated as "less is more."

If I were shopping for a light, I would look at the best light my budget could afford that would physically fit my space ... and then use the dimmer to set the intensity for the grow. The lux idea is valid. So is using ppfd readings. You can even download a free app (there's more than one) that for most people, it will put you in the ballpark lighting wise of where you need to be.

More and more, people are using photone as their go-to freebie for lighting.

voltage said:

The se series uses evo i have 1. The g series uses the bridgelux.

Click to expand...

How much difference is there with Samsung vs Bridgelux? The watts are higher on that series with the bridgelux and it’s close to 4 feet long with a good spread for a 2x4 area.


Plus I can add the supplemental IR light easily to it with those dimensions. if anyone has comments on them I am skeptical of it being a bit of a marketing hoax with the short period of time your supposed to use them. According the the two companies that manufacture them currently.

I’m basically looking to make as strong and trichome encrusted buds as I can. I have some favorites from the years and when broken open they look a lot like moonrocks. That would be ideal.
My house is cursed with high tolerance so no reason to not shoot for the best I can do.

Gonna put it out there again. Sorry for the deep conversation on lights. I just don’t want to waste money.…..
Has anyone got experience with using the supplemental IR light bars to increase resin/trichomes?




Also are board lights inferior compared to bars? Again this is all about getting the best set of for the best price.

RoadKillSkunkHunt said:

I haven't read every post but from what I have read, it sounds like there's some things about lighting that you're trying to get a better grasp on.

Yes, there really is a "thing" called over-lighting. If you were to start browsing the grow diaries here, you'll see its actually fairly common with a new grower starting out. When it comes to growing top shelf cannabis, your motto should be "Everything in balance. Nothing in excess." You might even see it stated as "less is more."

If I were shopping for a light, I would look at the best light my budget could afford that would physically fit my space ... and then use the dimmer to set the intensity for the grow. The lux idea is valid. So is using ppfd readings. You can even download a free app (there's more than one) that for most people, it will put you in the ballpark lighting wise of where you need to be.

More and more, people are using photone as their go-to freebie for lighting.

Click to expand...

What light might that be? The spider farmer light I replied to voltage about is based on maximum length of the light bar compared to the space I have.
If I were to increase fixtures it would be based on a 2x4 footprint to work with table shelving like you’d see in a greenhouse.

Do you have input on the bridgelux vs Samsung conversation?

MJmadscientist said:

Gonna put it out there again. Sorry for the deep conversation on lights. I just don’t want to waste money.…..
Has anyone got experience with using the supplemental IR light bars to increase resin/trichomes?




Also are board lights inferior compared to bars? Again this is all about getting the best set of for the best price.

Click to expand...

Yes, I run both 730nm IR and 660nm deep red. Here's a write up I did on my experience with using those supplemental spectrums. I've also run 440nm supplemental blues. I definitely notice differences using the supplemental reds and blues ... but when I ran UV I didn't notice any differences. Here's a report I wrote on my experiences.

Advanced Spectrum Manipulation in Cannabis Cultivation - Experimental Report​

Executive Summary​

This report documents a series of controlled experiments investigating the effects of targeted wavelength supplementation on cannabis plant architecture, yield, and quality characteristics. Through systematic manipulation of specific light spectrums (440nm blue, 660nm red, 730nm far-red), significant control over plant morphology and secondary metabolite production was achieved while maintaining craft-level flower quality.

Experimental Period​

Duration: September 1, 2024 - June 4, 2025
Growing Space: 5' x 5' cultivation area
Experimental Runs: 2 completed, 1 planned

---

Run #1: Initial Red Spectrum Supplementation​

Protocol​

Supplemental Lighting: 660nm red + 730nm far-red LEDs
Timing: Synchronized with main lighting schedule (standard photoperiod)
Duration: September 2024 - January 2025

Results​

Plant Architecture:

Significant stem elongation observed
Increased internode spacing

Quality Characteristics:

Heavy trichome development ("heavily frosted")
Abundant terpene production
Craft-level flower quality achieved

Yield Impact:

Reduced overall yield due to energy allocation toward stem development
Loss of productive flower sites due to excessive stretch

Analysis​

The constant supplementation of 660nm and 730nm wavelengths triggered phytochrome-mediated shade avoidance responses, resulting in beneficial stress that enhanced secondary metabolite production while compromising structural efficiency for yield optimization.

---

Run #2: Advanced Spectrum Timing Protocol​

Protocol​

Supplemental Wavelengths:

440nm blue
660nm red (increased intensity from Run #1)
730nm far-red (increased intensity from Run #1)

Timing Schedule:

440nm Blue: 18-hour photoperiod throughout vegetative stage and continued through first 14 days of 12/12, then discontinued
660nm Red: 10 minutes pre-light activation, full photoperiod, 10 minutes post-light extension
730nm Far-red: 30 minutes pre-light activation, OFF during main 12-hour photoperiod, 30 minutes post-light extension

Results​

Vegetative Growth:

Super lush, healthy plant appearance during vegetative stage
Enhanced vigor from full spectrum supplementation
Robust structural development

Plant Architecture:

Complete elimination of stretch
Extremely compact growth structure
Tight internodal spacing maintained throughout flowering

Quality Characteristics:

Maintained craft-level flower quality
Excellent trichome development
Superior terpene profiles preserved

Yield Performance:

Total Harvest: 3+ pounds from 5' x 5' space
Yield Limitation: Suboptimal canopy coverage due to excessive compaction
Space Utilization: Underutilized growing area potential

Analysis​

The extended blue light exposure throughout vegetative growth and into early flowering effectively locked in compact architecture, preventing any stretch response even after discontinuation at day 14 of flower. The full spectrum supplementation during vegetative growth (440nm + 660nm + 730nm) produced exceptionally vigorous and healthy plant development, creating an optimal foundation for flowering. While this solved the elongation issues from Run #1, it overcorrected and limited canopy development needed for maximum space utilization.

---

Planned Run #3: Optimized Dual-Phase Protocol​

Hypothesis​

Strategic timing of blue light supplementation can achieve optimal balance between canopy development and quality enhancement by targeting distinct physiological phases of flower development.

Proposed Protocol​

Vegetative Stage:

440nm Blue: 18-hour photoperiod alongside main lighting
660nm Red: 18-hour photoperiod alongside main lighting
730nm Far-red: 18-hour photoperiod alongside main lighting

Phase 1: Structural Development (Week 1-3 of 12/12)

440nm Blue: OFF (allowing natural stretch for canopy fill)
660nm Red: 10 minutes pre-light activation, 10 minutes post-light extension
730nm Far-red: 30 minutes pre-light activation, OFF during main 12-hour photoperiod, 30 minutes post-light extension
Main Lighting: 12/12 photoperiod

Phase 2: Flower Maturation (Week 3+ of 12/12)

440nm Blue: Resume 12/12 timing alongside main lighting (quality enhancement focus)
660nm Red: Continue 10 minutes pre-light, 10 minutes post-light timing
730nm Far-red: Continue 30 minutes pre-light, 30 minutes post-light timing
Main Lighting: Continue 12/12 photoperiod

Expected Outcomes​

Canopy Development: Adequate stretch in weeks 1-3 for optimal space utilization
Quality Enhancement:Blue light reintroduction during flower development to stimulate:

Enhanced trichome production
Improved terpene synthesis
Increased flower density

1. Yield Optimization: Balanced approach targeting both quantity and quality metrics

---

Key Findings and Principles​

Spectrum-Specific Effects Documented​

660nm Red:

Primary photosynthetic enhancement
Supports overall plant metabolism
Effective as pre/post photoperiod extension

730nm Far-red:

Controls stretch response via phytochrome system
Timing-dependent effects on plant architecture
Strategic scheduling prevents excessive elongation

440nm Blue:

Powerful compaction tool
Effects persist beyond exposure period
Critical timing for balancing stretch vs. compaction
Potential quality enhancement during flower maturation

Cultivation Philosophy​

Light spectrum manipulation serves as a precision tool for "sculpting" plant architecture and metabolic responses. Each wavelength functions as a specific instrument requiring strategic application based on desired outcomes and growth phase requirements.

Prerequisites for Advanced Protocols​

Successful implementation of complex spectrum manipulation requires:

Mastery of fundamental growing techniques
Consistent environmental control
Systematic experimental approach
Detailed documentation and analysis

---

Recommendations for Implementation​

For Experienced Growers​

Begin with single-wavelength experiments before complex timing protocols
Maintain detailed records of plant responses to timing changes
Consider genetics-specific responses in protocol development

Critical Success Factors​

Environmental Stability: Maintain consistent temperature, humidity, and airflow
Baseline Consistency: Ensure all other variables remain constant during experiments
Timing Precision: Use programmable controllers for accurate spectrum scheduling
Documentation: Record morphological changes, quality metrics, and yield data

Future Research Directions​

Strain-specific spectrum response profiles
Integration with environmental control systems
Long-term effects on plant stress and resilience
Optimization of spectrum intensity levels

MJmadscientist said:

What light might that be? The spider farmer light I replied to voltage about is based on maximum length of the light bar compared to the space I have.
If I were to increase fixtures it would be based on a 2x4 footprint to work with table shelving like you’d see in a greenhouse.

Do you have input on the bridgelux vs Samsung conversation?

Click to expand...

Samsung makes the slightly more efficient LED. However, Bridgelux are also high quality so we're splitting hairs over the differences. In one of my tents, I have two ROI-E720's. They use both Samsung and Bridgelux chips. I have a 630 watt Nanolux LED light in my other flower tent. It also uses both Samsung and Bridgelux chips. In my fixtures, the brdigelux chips handle the deep red (660nm) and far red (730nm) wavelength while the Samsung chips power the white light part of the fixtures. Your in good hands with either or both chips being used in your fixtures.

Its Epiled that you should look out for. They aren't horrible, but are not of the same quality of either Samsung or Bridgelux.

As for the Spider Farmer fixture you mentioned, the light's physical footprint sounds like a very good fit for your space. However, be aware that you will probably spend most of your grows lighting that space with between 40% and 80% of its capacity. This is a valid approach. You drive your lights a lot softer so they last a lot longer than if they were always running at 100%.

MJmadscientist said:

Gonna put it out there again. Sorry for the deep conversation on lights. I just don’t want to waste money.…..
Has anyone got experience with using the supplemental IR light bars to increase resin/trichomes?




Also are board lights inferior compared to bars? Again this is all about getting the best set of for the best price.

Click to expand...

I'm not sure I would state that quantum boards are inferior. My vegging tent has two 240 watt quantum boards. The big thing about boards vs bar lights is you need to use them slightly different. The boards have hot spots where the bar lights tend to be much more uniform in their lighting. It's the chip quality you need to pay attention to ... for example, is the fixture using either Samsung or Bridgelux chips? If they are using either or both of those brands, the light is likely worth purchasing.

You should never purchase a grow light that doesn't have a dimmer.

When i purchased my quantum board light 5yrs ago from Viparspectra it had Samsung diaods. They don't sell the P2500 anylonger but i love it never failed yet. I know old tech but it's been through many many grows.