Light height - commercial vs home grow

[Pwyll]

From what I have seen most large commercial facilities leave the lights at a fixed height so as the plant grows it gets closer to the light. Whereas home growers favor keeping the lights at a set height above the canopy, raising them as the plant grows.

Is that characterization broadly accurate?

 

[thailer]

i've worked at two commercial facilities in washington. One was one of the largest cultivators and had a total of 43 rooms. it depends on the room and what type of lights they had going but all lights were at a fixed height on a shelf system. mostly LED and T5 in veg with LED and double ended in bloom.

The other one was a small grow that didn't have the money that the mega grow did and so they bought HPS lights and those I did have to lower and raise once in bloom. there was a total of 6 rooms with one of them dedicated to veg only. just to give an idea.

i interviewed at another farm and their bloom room is also fixed lights so yes broadly, they're fixed but I think it depends on who you're working for. theres these mega walmart weed world grows where they're telling you they purchased 12 different brands of LED lights and they all suck. lol a lot of the farms though are small with only one or two employees and so you will see less professional set ups.

i think the money aspect into what type of lights you can buy, can you grow inside an actual room or limited to a tent so you can have a tall ceiling, and how many plants are you growing dictate how the lights are set up. I have my bloom room fixed at the ceiling and it never moves. its a double ended and i have nine foot tall height. i think it's mostly because home growers have limited height and area to grow in.

 

[xxPeacePipexx]

It just depends upon your preferences and the lights output. In the homegrown world you will find more configurations then imaginable. Low watt lights in general need to be kept close to the tops of the plants and the higher the wattage the higher the distance. I have to keep my lights at home fixed, due to my disabilities. But I just raise individual plants if necessary to compensate.

 

[art.spliff]

Commercial growing is done differently. The lights are way too high often times, and plants are vegged long enough to stretch and become leggy reaching toward the lights.

Commercial growers have used this style for years. Holding my tongue, as I am not a commercial grower and want to be careful about armchair coaching, just because a method is used in production doesn't mean it is necessarily very good, or great.

Cannabis has still been in the shadows and the high price of the product means that commercial cultivators can get away with very inefficient designs. These are grows that would fail economically if used for squash, tomatoes, or corn.

It isn't easy to attempt to explain mathematically, all the wasted light and power usage, but you can see it looking at different rooms.

An intensively managed grow might have smaller lights or closer plant spacing until the canopy is full. Instead there are large warehouse facilities that veg clones 9 feet below hps lights for example. Or maybe they use the dimming feature for veg. Instead of a closer or smaller light.

Plant count (or propagation labor), veg time, and spacing are all factors to consider. I don't know the ideal numbers but any plants taller than about 18-24" and any trellis net squares missing colas are inefficient use of space/power and resulting value.

A sea of green with 4 plants per square foot will yield well with little veg time but what a chore taking cuttings. Similarly, less plants can be trellised horizontally (or vertically) and grown in a vegetative state for a longer period of time. A full screen of green might take 1, 3, or 5+ weeks in veg depending on size/spacing but the resulting yield is greater than untrellised plants with less veg time.

All the little things add up. When size scales up, other parts are compromised. It doesn't necessarily mean that efficiency is poor or quality is poor or worse than a smaller operation. In fact larger operations like to brag they are better at everything. But often the opposite is true.

The largest, most advertised or notable operations, that like to draw investing attention among other things, quite frequently lack in product quality.

Again I have no correlation or graph to show here, it is only my experience. If you've heard of the name because you saw it on a billboard chances are it's overpriced crap because the company is there to turn profits nothing else.

If you find a place that doesn't advertise but is willing to help with advice or customer service you may have found a gem.

High intensity discharge lamps or HID fixtures, these have been in use for several decades. A metal halide light for warehouse bays, or high pressure sodium for streetlights, these are the same thing as growing lights.

Gavita is a brand name. What is likely is that cannabis growers were sold regular hps lights with double ended bulbs which look cheaper, cheap reflector, no cords, at a high markup.

Any light will work more or less the same. This doesn't necessarily include light emitting diodes because they are still somewhat new and less used.

1150 watts is a bright light (double ended hps) so the bulb must be kept further away and the light also has a greater effective distance.

2 600 watt hps fixtures for every 1 de hps I'm confident would work just as well if not better.

One thing that comes to mind, is commercial startups are limited to brand new equipment. They are going to pay whatever the retail seller asks for a new light fixture. Loading up on $20 used ballasts and other equipment perhaps should be, but often isn't an option for commercial operations.

Rather lure unsuspecting customers with continuous hype of everything being so valuable. This is the same whether you're talking about cars or tools or any other gadget. Swindlers always looking for suckers. Sometimes we see 40+ room warehouses of it.

This is when it gets hairy because those are sizable amounts of money and failures. You can't really call it a success unless the ridiculously overpriced lights pay for themselves. People might be a little hesitant or reluctant to learn they've been had and/or the plan was a failure from the start.

Saying to someone, that recently went through an expensive build process, that their setup is a failure from the start, isn't that easy to say or to hear. So it is unquestionably a scam from the very get go, with no intention of recuperating value. If a used ballast is $20 it doesn't justify $600 for a new light, only in a financed commercial setting full of salespeople.

Short version: higher lights is being lazy/less labor for a larger scale. If you tended 100 or 1000 grow lights by yourself you wouldn't have time to move them either. Plants in commercial grows don't receive much attention. The stuff coming out of many/most/all is garbage which I wouldn't want at any price. Same as a lot of other produce.

 

[Lyfespan]

From what I have seen most large commercial facilities leave the lights at a fixed height so as the plant grows it gets closer to the light. Whereas home growers favor keeping the lights at a set height above the canopy, raising them as the plant grows.

Is that characterization broadly accurate?

commercial we light the room not the plant

 

[popta]

The different styles are due to the different number of lights used by large vs small growers and also the influence of the mainstream greenhouse industry where shading is a concern so smallest reflector size is preferred.

When you only have one light you're needing a lot of work from your reflector. It has to get the light coming out of your bulb, ALL the light, focused onto a tight little 4x4 square AND it has to somehow spread it evenly over that area AND the beam has to be very tightly focussed or the light strength will vary a lot depending on the distance between light and plant.

Well no reflector can really do all this. And trying makes the reflector huge. So smaller growers raise and lower the light to maintain light levels because we have to.

In a large scale facility you're not trying to focus a single light on a single square, you're using a grid of overlapping lights each with a wide spread to create an even light level over the entire crop. You only need a small reflector for this, so shading is minimized, and thanks to the grid of multiple lights falloff over distance is greatly reduced. Apparently you can double the distance to the lights and lose less than 10% of the light intensity so I guess at that point it's not worth it to pay someone to constantly adjust the height of all those lights.

 

[Lyfespan]

running DE HPS of course at 11' off the floor, tables are 1 1/2' off floor, each light is set so we have a 30% overlap on the beam spreads

 

[art.spliff]

Apparently you can double the distance to the lights and lose less than 10% of the light intensity so I guess at that point it's not worth it to pay someone to constantly adjust the height of all those lights.

Mind clarifying this? Rather the light fixture distribution in indoor with greenhouse style reflectors as you put it, where there is no natural sunlight, appears as though little to no concern was given for the monetary (money) and environmental (carbon) cost of the artificial light. Energy cost or power consumption, and startup cost or retail price are disregarded in favor of simple convenience and some monetary profit.

In theory it makes little difference if you use 100 watt bulbs, 1000/1150w, or 10,000w bulbs, with similar efficiency, correct?


I have some difficulty relating this graph to canopy growth for plants. There is likely a sweet spot, or minimum and maximum ideal distance, for a given light. The total available light for plant growth at two meters is less than at one meter, correct? Otherwise raising the light would be the same as increasing reflector angle?


Case 1: Light has a spot light reflector, like a flash light. Place light far enough away for 4 x 4 coverage.
Case 2: Light with parabolic or bat wing placed closer for 4 x 4 coverage.
Are these the same? More of a physics question, but a real world test works too.

 

[Lyfespan]

Mind clarifying this?


View Image

this shows the beam spread and dismishment this allows you to understand whats happening to your light over distances

its just showing it horizontally instead of vertically

 

[Mikell]

running DE HPS of course at 11' off the floor, tables are 1 1/2' off floor, each light is set so we have a 30% overlap on the beam spreads

Ta Da

 

[Lyfespan]

each reflector is manufactured to give a specific beam spread, wide 60degree+, flood40+, narrow 20+, or spot1 10degree -. and each light has a lumen value 120,000+

 

[Lyfespan]

Ta Da

people forget how crucial overlap is for consistent lighting, dot forget that the edges of beam spread are your weakest areas, you fix this with over lap and every rooms overlap is different. knowing this is key to proper even canopy

 

[Lyfespan]

lumen, lux, par, PPFD, umol, umol J, watt all terms you should research

 

[Absolem]

The more lights used in a grow the better the light penetration becomes. No need to raise or lower the lights.

This is a good read from Gavita on how much more effective light penetration becomes when several lights are used.

https://gavita.com/retail/app/uploads/How-to-design-an-optimal-growroom.pdf

Winner winner chicken dinner.

commercial we light the room not the plant

 

[art.spliff]

What about case 1 case 2 from the previous page? Only posted gavita literature i.e. reading the box. If a 40 degree reflector at a greater distance is the same as an 80 degree reflector closer it would be helpful to know without looking up vocabulary words. Too much technical jargon only reduces clarity in explanation sometimes if not always. Literature from the light manufacturer isn't a reliable source in this circumstance.

 

[Absolem]

You haven't answered my question about case 1 case 2 from the previous page. Only posted gavita literature i.e. reading the box.

The literature is out there on commercial lighting if you look.

Not going to get into it with a person that doesn't understand how lighting works in a commercial grow.

It's like debating a person who uses bottle nutrients when talking fertilizer nutrition.

 

[Lyfespan]

You haven't answered my question about case 1 case 2 from the previous page. Only posted gavita literature i.e. reading the box. If someone knows the answer (40 degree reflector at a greater distance = 80 degree reflector closer) without reading about all of the different vocabulary terms for light it would be helpful. Too much technical jargon only reduces clarity in explanation sometimes if not always. Posting literature from the light manufacture is not a reliable source in this circumstance.

so can we just come do it for you? that way you still dont know what youre doing?

trying to teach you to figure it out

 

[Lyfespan]

The literature is out there on commercial lighting if you look.

Not going to get into it with a person that doesn't understand how lighting works in a commercial grow.

It's like debating a person who uses bottle nutrients when talking fertilizer nutrition.

if they haven't stopped paying for water, you cant help them

 

[art.spliff]

More lights evens out the distribution vs one light, that I understand. What about reflector angle and light distance, are the two interchangeable?

1) With (100) 100w lights or (10) 1000w lights or (1) 10000w light is plant growth potential the same e.g. 1 gram per watt?

2) Does a narrow angle reflector placed further away behave the same as a wide angle reflector placed closer with respect to yield (growth photosynthesis)? In other words does a spot light reflector 10+ feet away provide the same amount of light as a large parabolic closer to the canopy?

Edit: leaning toward the answers to these two being yes, thinking about lasers.

If photons are conserved and only spread with distance then reflector shape and light distance are less important overall. Meaning bare bulbs or pie tin reflectors or any reflector will perform similarly. I think physics textbooks use the term assume no losses due to friction, air resistance, etc.

 

[Absolem]

All the answers you are asking are located in the Gavita literature I posted.

The answer you are looking for on light loss and height are on pages 3 and 4
The umol calculations for height and light loss are there.

https://gavita.com/retail/app/uploads/How-to-design-an-optimal-growroom.pdf

Or you can check P.L lighting Systems. They are the leading light producer for commercial grows.