How do you properly measure PPFD?

[SanAmorous]

Is PPFD measured per plant OR per sqaure meter for the total number of plants within that meter measurement?

In example:

Let's say I'm aiming for 200 PPFD and I'm using the Photone app on my phone to measure PPFD, do I take the reading from the center of the plant (adjusting the light to output 200 ppfd centerpoint if necessary)

OR


Do I measure each corner of the square meter (with each corner needing to read at about 50 ppfd to total up to 200 ppfd)?

 

[LoveGrowingIt]

The PPFD varies depending on where it's measured. It's usually measured at the crown of the plant. It's typically the highest directly under the light.

Let's say I'm aiming for 200 PPFD and I'm using the Photone app on my phone to measure PPFD, do I take the reading from the center of the plant (adjusting the light to output 200 ppfd centerpoint if necessary)

Yes.

Do I measure each corner of the square meter (with each corner needing to read at about 50 ppfd to total up to 200 ppfd)?

No.

 

[SanAmorous]

The PPFD varies depending on where it's measured. It's usually measured at the crown of the plant. It's typically the highest directly under the light.


Yes.


No.

The only thing that confuses me about this proposal is that if you're growing multiple plants with one light, either you'd have to have an extremely powerful light to have thr centerpoint of each plant reading the same PPFD or each plant would need its own individual light or supplemented lighting.

The m² point is in the middle of a square meter. I'm not sure if this is what you mean or not.

 

[BB22]

My unasked for .02

And I’m a noob

Why are you so complicated about it? Put the measuring device over the top of your plant. Find out where you’re at and let it rip. If I’m missing something correct me. no disrespect intended.

 

[SanAmorous]

My unasked for .02

And I’m a noob

Why are you so complicated about it? Put the measuring device over the top of your plant. Find out where you’re at and let it rip. If I’m missing something correct me. no disrespect

Well approaching it that way would only make me even more complicated because then my next question would be if DLI is based in a m² measurement per square meter, then why isn't it measured per plant instead. One plant doesn't take up one square meter. Multiple plants can fit within a square meter. You're saying measure from thr center of the plant but every plant isn't going to be at the same DLI reading under the same light.

That's where the complication lies for me. If every plant within that square meter of space is suppose to be receiving the same DLI at its crown center as every other plant. And if so, uncomplicate things for me and tell how to go about ensuring this without light stressing the plants.

 

[mrsdabfire]

Is PPFD measured per plant OR per sqaure meter for the total number of plants within that meter measurement?

In example:

Let's say I'm aiming for 200 PPFD and I'm using the Photone app on my phone to measure PPFD, do I take the reading from the center of the plant (adjusting the light to output 200 ppfd centerpoint if necessary)

OR


Do I measure each corner of the square meter (with each corner needing to read at about 50 ppfd to total up to 200 ppfd)?

PPFD (Photosynthetic Photon Flux Density) is typically measured per square meter (PPFD/m²) and represents the total amount of photosynthetically active radiation (PAR) falling on a given area. It is not measured per plant.

When measuring PPFD in a grow space, it is important to consider the total area covered by the canopy of all the plants within that space. The PPFD value obtained represents the average light intensity over that entire area.

To ensure that each plant receives sufficient light, you should measure PPFD at various points within the canopy and adjust the lighting accordingly. This helps to create a uniform light distribution and minimizes the risk of light-related issues such as stretching or light bleaching.

Here are some key points to remember about PPFD measurement:

• PPFD is measured in micromoles per square meter per second (µmol/m²/s).
• It represents the total amount of PAR (light wavelengths between 400-700nm) falling on a given area.
• PPFD is typically measured using a quantum meter or PAR meter.
• Growers should measure PPFD at various points within the canopy to ensure uniform light distribution.
• Optimal PPFD levels for cannabis plants can vary depending on the growth stage and strain, but generally range from 400-1000 µmol/m²/s.

By understanding and measuring PPFD effectively, you can optimize your lighting strategies to maximize photosynthesis and promote healthy plant growth and development.

 

[Week4Bytch]

The only thing that confuses me about this proposal is that if you're growing multiple plants with one light, either you'd have to have an extremely powerful light to have thr centerpoint of each plant reading the same PPFD or each plant would need its own individual light or supplemented lighting.

The m² point is in the middle of a square meter. I'm not sure if this is what you mean or not.

Just use the tool to get what you can get. If you need more/better lighting solution, then that's what you need. Hanging the light higher helps with even lighting, adding more light helps with even lighting, etc, the tools are there to help you.

 

[SanAmorous]

PPFD (Photosynthetic Photon Flux Density) is typically measured per square meter (PPFD/m²) and represents the total amount of photosynthetically active radiation (PAR) falling on a given area. It is not measured per plant.

When measuring PPFD in a grow space, it is important to consider the total area covered by the canopy of all the plants within that space. The PPFD value obtained represents the average light intensity over that entire area.

To ensure that each plant receives sufficient light, you should measure PPFD at various points within the canopy and adjust the lighting accordingly. This helps to create a uniform light distribution and minimizes the risk of light-related issues such as stretching or light bleaching.

Here are some key points to remember about PPFD measurement:

• PPFD is measured in micromoles per square meter per second (µmol/m²/s).
• It represents the total amount of PAR (light wavelengths between 400-700nm) falling on a given area.
• PPFD is typically measured using a quantum meter or PAR meter.
• Growers should measure PPFD at various points within the canopy to ensure uniform light distribution.
• Optimal PPFD levels for cannabis plants can vary depending on the growth stage and strain, but generally range from 400-1000 µmol/m²/s.

By understanding and measuring PPFD effectively, you can optimize your lighting strategies to maximize photosynthesis and promote healthy plant growth and development.

This is very close to the sensible answer I was looking and clears up a lot of confusion and also helps me understand how LED panels actually distribute light to a canopy. Thank you for taking the time to explain.

 

[Pilted]

You are asking the wrong question.

What you should be asking is how do I tell if I need more light or less light from what the plant is doing.

The ppfd meters should only be used as a tool to give you a rough idea on what the light intensity is not as a guide were your light should be. For example I have a bubba kush and norther light growing one is at 930 ppfd the other is at 600 ppfd both growing great but since they are different strains they require different intensities. Then you have the fact that plants need different intensities for different stages, seedling, veg, early flower mid flower, and late flower. Trying to determine how much light you need with a ppfd reading will lead to failure.

Now how to read the plant, if at the end of the day your plant is in a praying stance, this means you need more light. If your plant leaves are droopy at the end of the day it means you need less light. If your leaves are flat you are at about the right light. Now this is just looking at all the leaves of the plant from a few feet away.

If looking at a individual leaf. If it is looking like a taco you need to reduce light, if looking like the edges are pointing downwards (droopy) not enough light. If the leaf is flat edges not raised or lowered then you are at the right light.


Don't rely on the ppfd meter readings, it's a mistake.

 

[SanAmorous]

You are asking the wrong question.

What you should be asking is how do I tell if I need more light or less light from what the plant is doing.

The ppfd meters should only be used as a tool to give you a rough idea on what the light intensity is not as a guide were your light should be. For example I have a bubba kush and norther light growing one is at 930 ppfd the other is at 600 ppfd both growing great but since they are different strains they require different intensities. Then you have the fact that plants need different intensities for different stages, seedling, veg, early flower mid flower, and late flower. Trying to determine how much light you need with a ppfd reading will lead to failure.

Now how to read the plant, if at the end of the day your plant is in a praying stance, this means you need more light. If your plant leaves are droopy at the end of the day it means you need less light. If your leaves are flat you are at about the right light. Now this is just looking at all the leaves of the plant from a few feet away.

If looking at a individual leaf. If it is looking like a taco you need to reduce light, if looking like the edges are pointing downwards (droopy) not enough light. If the leaf is flat edges not raised or lowered then you are at the right light.


Don't rely on the ppfd meter readings, it's a mistake.

Another sensible response. Thank you for explaining this.

 

[climbit]

Well approaching it that way would only make me even more complicated because then my next question would be if DLI is based in a m² measurement per square meter, then why isn't it measured per plant instead. One plant doesn't take up one square meter. Multiple plants can fit within a square meter. You're saying measure from thr center of the plant but every plant isn't going to be at the same DLI reading under the same light.

That's where the complication lies for me. If every plant within that square meter of space is suppose to be receiving the same DLI at its crown center as every other plant. And if so, uncomplicate things for me and tell how to go about ensuring this without light stressing the plants.

I knew I should of stayed in school.

 

[LoveGrowingIt]

It can be helpful to keep in mind that (for most LED panels) the light is most intense directly under the light and is significantly less intense in the periphery. Acknowledging that much depends on the specifics of the grow, for me, a small-time grower, one light per plant seems to work best.

 

[Gmix]

One light per plant jeeps I would need a lotta lights guess it depends on what the light puts out however I couldn’t imagine needing 9 x 400w leds for a few plants

 

[SanAmorous]

One light per plant jeeps I would need a lotta lights guess it depends on what the light puts out however I couldn’t imagine needing 9 x 400w leds for a few plants

Not to mention how it would astronomically raise the temperature in your grow space. I have two Mars Hydro Reflector 22 lights that use 130 watts each and they raise the temperature up to 10° from room temperature in a 4x3×6. Nine lights running at one time, you'd need a very big grow space.

 

[SanAmorous]

It can be helpful to keep in mind that (for most LED panels) the light is most intense directly under the light and is significantly less intense in the periphery. Acknowledging that much depends on the specifics of the grow, for me, a small-time grower, one light per plant seems to work best.

Does it significantly raise the temperature of your grow space? Or you only grow 2 or 3 plants at a time?