Optimal Plants per Light for This Set-up?

[Shiva Blaster]

Hi!

In the planning stages of a commercial medical grow.....we have everything worked out in detail, except for deciding how many plants per light would be the best for our set-up.

This grow will be small to start out with, with room for easy expansion with time in a 2500 sqft warehouse-type facility that we are purchasing. To begin, we will have 3 x 600 sqft flower rooms (15'x20'), each completely sealed with mini-split A/C, dehuey, CO2 generators, and 6 x 1000W air-cooled lights with 8" XXXL hoods. The 3 flower rooms will run in a perpetual harvest, with one of the 3 coming ready every 3-3.5 weeks. One room will be for heavy indicas, one for hybrids, and one for sativas.

We do not yet have a plant limit, but with our small size, this should not be a huge issue. We are growing 100% organically in fabric smart pots. Container size has yet to be determined, as it is obviously tied to the plant count we choose. The main concern here is efficiency....short of trimming, this will operation will be 100% run by myself once the construction phase is completed. What would the more experienced commercial growers here suggest in terms of optimum veg times, plants-per-light counts (for indicas and sativas, we will be growing multiple strains), and containers sizes to optimize this set-up given the parameters listed? We obviously have a large mother, clone room that will be feeding these flower rooms.

Thanks in advance for any suggestions/recommendations!

 

[Shiva Blaster]

Bump!

 

[Shiva Blaster]

Really? a couple of days and 30+ viewers and not one person has an opinion on this?

 

[packerfan79]

I would think 4-6 plants per light. But I'm not any where close to that big

 

[Elite Nugz]

There's no generic plant number per light. Nor is there a generic veg time. Some strains veg fast, some veg slower. Faster veggers will obviously require shorter veg times. Also better rooted/stronger clones will take off faster then clones that didnt root as well.

Plant numbers per light depend on how big the plants are going into flowering. The bigger the plant is, the fewer plants you'll need to fill in your space. You can go 16+ plants per 1000 watt light if there starting small. I've done as few as 3 plants per 1000 watt light, because I trained them into short bushes.

So its really about plant size, and making sure you fill in your entire space under your light. If you leave too big of gaps between plants, then your just going to be wasting light. If you pack too many close together, then you'll block out too much light from being able to penetrate the canopy for good yields

You need to get to know your strains, to determine how fast they grow, how bushy they get, how much they stretch in flower, etc. I mainly grow OG's that stretch like crazy in flowering, so I can pop in 12, 1 foot OG's under a 1k light, and by the 4th week of flowering, I'll have 3-4 foot tall plants with a completely filled in canopy and pull anywhere between 1.75-3 lbs per 1k light.

 

[Elite Nugz]

But if you didnt know this.... a warehouse size grow, might be a little out of your league. No offense though.

Most people think they can jump from a garage or bedroom up to a warehouse and do things the same, but on a bigger scale and accomplish the same results.... but its doesnt work that way. A bedroom grow compared to a warehouse grow is an entirely different ballgame.

 

[Elite Nugz]

For instance... your mini-splits... Those work great in a small setting... but dont work well at all in a warehouse setting. Your going to have a cold spot in front of your mini-split, while the opposite side of your room is gonna be hot, no matter how many fans you have. Cold air doesnt stay cold going from one side of a 20 ft long room to the other. You need to run ducting and vents, to evenly distribute the cold air.

And thats just one small issue you'll deal with going from a small grow to a big grow. There totally different in just about every way... but I wish you luck. We all have to learn some way.

 

[Asslover]

Plants per light is completely subjective. Really. I've done everything from 9 plants under 600w to 9 under 1000w and finally 4 per 1000w. My best #'s happen with 4 per light. Plant size (height and girth) also play a role is how many per light. Style of growing is also a factor.
As for the mini splits, rooms that big will do better with a dual head mini split. One head mounted opposite wall of the other.
You could get away with a single larger btu head by putting a few oscillating fans about the room but 2 lesser btu heads are better. For example, two 18k btu heads instead of one 36k btu...

 

[Elite Nugz]

You could get away with a single larger btu head by putting a few oscillating fans about the room...

This will still make half of your room colder then the other half.

Absolute most efficient way, is ducting and vents, to spread the cold air evenly.

 

[Asslover]

This will still make half of your room colder then the other half.

Absolute most efficient way, is ducting and vents, to spread the cold air evenly.

I happen to use two mini splits, one in veg, one in flower) and can tell you from experience that one side of the room will only be a few degrees warmer (or colder) than the other, provided he/she uses oscillating fans on either side of the room. My thermometer says so
You cannot duct mini splits but the next best thing is two indoor units mounted opposite ends of the room.

 

[Shiva Blaster]

There's no generic plant number per light. Nor is there a generic veg time. Some strains veg fast, some veg slower. Faster veggers will obviously require shorter veg times. Also better rooted/stronger clones will take off faster then clones that didnt root as well.

Plant numbers per light depend on how big the plants are going into flowering. The bigger the plant is, the fewer plants you'll need to fill in your space. You can go 16+ plants per 1000 watt light if there starting small. I've done as few as 3 plants per 1000 watt light, because I trained them into short bushes.

So its really about plant size, and making sure you fill in your entire space under your light. If you leave too big of gaps between plants, then your just going to be wasting light. If you pack too many close together, then you'll block out too much light from being able to penetrate the canopy for good yields

You need to get to know your strains, to determine how fast they grow, how bushy they get, how much they stretch in flower, etc. I mainly grow OG's that stretch like crazy in flowering, so I can pop in 12, 1 foot OG's under a 1k light, and by the 4th week of flowering, I'll have 3-4 foot tall plants with a completely filled in canopy and pull anywhere between 1.75-3 lbs per 1k light.

I am well aware of all of this, I am an experienced grower. I have never grown perpetually though in a 3 room set-up like this, so I was simply looking for opinions on the most efficient plant/light count given the parameters provided. My original plan was to grow 4 large trees per light with a 5-6 week veg, which is how I normally like to grow.....was just looking for input from any growers that run a similar set-up to see how they dow things.

 

[Shiva Blaster]

For instance... your mini-splits... Those work great in a small setting... but dont work well at all in a warehouse setting. Your going to have a cold spot in front of your mini-split, while the opposite side of your room is gonna be hot, no matter how many fans you have. Cold air doesnt stay cold going from one side of a 20 ft long room to the other. You need to run ducting and vents, to evenly distribute the cold air.

And thats just one small issue you'll deal with going from a small grow to a big grow. There totally different in just about every way... but I wish you luck. We all have to learn some way.

I will have to disagree here.....have some contacts that run bigger rooms than my 20 x 15 rooms with mini-spilts extremely successfully with negligible temperature gradient across the room with proper in-air circulation. Lot's of great videos on YouTube as well of bigger rooms using mini-splits with great success as long as you are getting the correct size and have proper air circulation.

I'm not sure if you mean for your posts to come across as condescending or not (it's tough to tell in text sometimes), but I am well aware of what I am doing here and a lot of time, effort, and research has been done planning our rooms, and I'm quite confident with our set-up.

With all due respect, I asked a simple question regarding optimum veg time and plant counts to optimize the efficiency of my set-up, not a critique of my room design.

 

[Shiva Blaster]

Plants per light is completely subjective. Really. I've done everything from 9 plants under 600w to 9 under 1000w and finally 4 per 1000w. My best #'s happen with 4 per light. Plant size (height and girth) also play a role is how many per light. Style of growing is also a factor.
As for the mini splits, rooms that big will do better with a dual head mini split. One head mounted opposite wall of the other.
You could get away with a single larger btu head by putting a few oscillating fans about the room but 2 lesser btu heads are better. For example, two 18k btu heads instead of one 36k btu...

Thanks for your reply. My best crops have been will 4 per light as well, but have seen most big growers going with a lot more than that.....just wanted to see what others would do and why given my arrangement.

Each room will have 8 x 18" oscillating fans, so more than 1 per light......should be lots of air flow for a single mini-split I would think, each one will be 32,000 btu. I also have one 8" fan per 3 hoods cooling the lights.

 

[Shiva Blaster]

I happen to use two mini splits, one in veg, one in flower) and can tell you from experience that one side of the room will only be a few degrees warmer (or colder) than the other, provided he/she uses oscillating fans on either side of the room. My thermometer says so
You cannot duct mini splits but the next best thing is two indoor units mounted opposite ends of the room.

This is what I'm saying. My buddy's room is only 2 degrees F from the coolest spot to the warmest.....with a single mini-split unit per room. I hardly think that warrants the extra cost and pain in the ass of a second unit per room or a bunch of extra fans and ducting. I'm all for optimum conditions and doing things the right way, but that is just going overboard IMO. Now having fully automated environmental controls isn't enough, you can't have temps vary by a degree or two across a room????? C'mon.... When I first started out, I was in my basement where I got 10-15 degree temp swings, and I always got very good results.....I'm pretty sure the plants will be just fine with 2-3 degree temperature gradient in a fully automated and controlled state-of-the-art grow room.

 

[Shiva Blaster]

And just to clarify, I'm not asking how many plants per light is best in general for yield..... I am well aware that you can have 16 plants or 1 plant and yield the same. I am asking for suggestions on the best veg times/plant counts/pot sizes to provide for the most efficient perpetual set-up given my situation. I will be doing almost everything myself, so efficiency is going to be key.

 

[Elite Nugz]

@Shiva Blaster Just trying to help brotha. Not trying to put you down or anything. I apologize if I came across that way.

I've been a warehouse grower for a long time now. I've tried using window units, mini-splits and big portable AC's. Now all I use are 5 ton split units (not mini-splits), with spiral ducting and vents that shoot out cold air between each table. I also use a Thermal gun to read the surface temps of my leaves under each light to make sure I dont have hot spots. The basic thermostats sold at most hydro stores arent very accurate, so I usually have at least 3 hanging at canopy level in each room to try and get a correct idea of the actual temps.

But back to your question... If your going for efficiency, then big monster plants usually arent the route to take. Higher numbers of smaller plants are the way to go, to keeping your perpetual cycle going, without wasting tons of electricity just to veg out monster plants. Smaller plants keeps things moving fast, and your veg times low.

Hopefully I helped in some way. Im sure you know what your doing though.

 

[Shiva Blaster]

@Shiva Blaster Just trying to help brotha. Not trying to put you down or anything. I apologize if I came across that way.

I've been a warehouse grower for a long time now. I've tried using window units, mini-splits and big portable AC's. Now all I use are 5 ton split units (not mini-splits), with spiral ducting and vents that shoot out cold air between each table. I also use a Thermal gun to read the surface temps of my leaves under each light to make sure I don't have hot spots. The basic thermostats sold at most hydro stores arent very accurate, so I usually have at least 3 hanging at canopy level in each room to try and get a correct idea of the actual temps.

But back to your question... If your going for efficiency, then big monster plants usually arent the route to take. Higher numbers of smaller plants are the way to go, to keeping your perpetual cycle going, without wasting tons of electricity just to veg out monster plants. Smaller plants keeps things moving fast, and your veg times low.

Hopefully I helped in some way. Im sure you know what your doing though.

Thanks man, I appreciate the reply and well wishes. I'm not a new grower by any means, but this is a big step for me and I'm aware that I'll have some things to learn.....I'm working my ass off and doing everything I can to learn, plan and prepare ahead of time. I was hoping to get some input from experienced pros like yourself when I started this thread, it's greatly appreciated.

I was more thinking about manpower.......less/bigger plants to water, prune, tend to. I'll be hand-watering and growing organically in pots, so tons of little plants would be a lot of work. I'll have 3 rooms and a large veg/mother room, so the cycle would go on regardless.....the first harvest would take an extra 2-3 weeks of initial veg time, but I'd still stagger my 3 rooms to pull a harvest every 3-3.5 weeks. I am in Canada, and our operation is going to be in a location that literally has the cheapest electricity in North America, so we are well prepared in that regard and luckily don't need to pinch pennies with power.

By using a big unit like you do, how would you hook it up to multiple rooms as in my case? Lighting cycles will be different, and each room will be completely sealed, so each room will have it's own cooling needs but is not big enough to need it's own massive 5 ton unit. Although the facility is 3500 sqft, we are starting small and manageable with only 3 x 600 sqft flower rooms and a 800 sqft veg room, with the ability to gradually add another 2-3 rooms in time if things are going well and we see fit. Would like to hear more details on how you run your unit to multiple rooms while still controlling each room's temps.

As far as plant numbers go, I originally planned on 4 per light as I like to grow shorter bushy plants with the use of topping and supercropping/LST. Then I starting thinking that I could go up to 6 plants per light for lankier sativas and hybrids, and 9 per light for indicas with a 4 week veg in 7 gallon smart pots.....this would shorten my veg by a couple of weeks and not be an unreasonable amount of extra work. What do you think about that?

 

[Elite Nugz]

I hope you dont mind a few pics.... but this is the way I usually lay out a grow.

Each room has its own 5 ton AC that ducted with spiral ducting above the ceiling and spreads out to each corner of the room and the middles through vents in the ceiling..


Here's a panoramic shot of one room from the blueprint above.

 

[Elite Nugz]

This is another 30 lighter I setup. Cant find the blueprints... but this is the last room in the building.

 

[Elite Nugz]

Im trying to find pics of my spiral ducting that gets distributed between each table. Give me a sec to try and find it.