Done with mirrors

I may try to find mirrors at thrift stores before shelling out for custom ones. I think I will need about 50 square feet.
 
Just did some cursory research on mirror cost, $9-13 high/low estimates per square foot.

The way I grow I will need a mirror 32-36" high. 14" from the floor to about 50". 20' perimeter so 60 sq/ft of mirror. Total cost for new mirrors = $540-780. If I can collect mirrors from thrift stores I can save a lot of money, but considering the extra light I can achieve and the fact that they will last a very long time, it would be worth it to purchase new if necessary.
 
So, there was a time gap between testing the flat white and the panda plastic. Cobs had warmed up so I wasn't being fair to the panda plastic. Temp droop should be in full effect now so I re-ran the experiment at the 6" distance. At any rate, all measurements for this test were taking within a minute. We can see the panda plastic score improving, being basically the same as the flat white. Ratios between control/flat white/mirror remain essentially unchanged. Mirror still more than double the increase of the other coatings.

Control - 174
Mirror - 224
Flat white - 192
Panda - 195
 
I found 4'x1' door mirrors at Walmart for $15 each. I would need 20 to cover my area. $300 bucks.

I'm thinking I may find a few used mirrors locally but probably not nearly enough to cover the walls. I'm going to shop around a little more, but $300 is looking pretty good to pick them up brand new.
 
My patience has payed off. A search today revealed 1'x4' mirrors at Home Depot for $5.96. Someone in a review mentioned taking the frames off for a workout room so I knew I could remove the frames without damaging them. I drove there expecting to have to order them but they had a stack of 50 or so.

They were on sale for $4.50 each! I grabbed 20 and took them to the front. The cashier scans them and tells me it will be $930. I point out they are 4.50 each and she apologizes stating she accidentally scanned in 200. It didn't bother me but because she gave me a "heart attack" she gave me a discount. The mirrors were now $4.25 each!

Total price $88.

Got them home with no breakage. I'll take a router to some wood strips, bag of screws. I'll get out for under $100 total.

Here's the link if anyone is interested: https://www.homedepot.com/p/MCS-13-...PIPHorizontal2_rr-_-205513210-_-300867223-_-N
 
I'd imagine that anything toward the bottom of the walls won't really matter anyway unless you're trying to reflect far-red. Don't tell anyone, but I just tape aluminum foil to the walls of my veg box. (common noob mistake.. shhh)
 
churchhaze said:
Don't tell anyone, but I just tape aluminum foil to the walls of my veg box. (common noob mistake.. shhh)
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How will you ever keep up with the big dogs?!

The original idea was to have the mirror surface from 12" above the floor to 48" (3 feet). Since these are 4 feet tall I could get by with them on the floor, but I'll probably raise them 6"-12" anyway.

After playing around with one I'm finding it's not easy to remove the frame. There's a sticky plastic sheet covering the back. I was hopeful that was all since it's possible to pull it off by hand, albeit very slow process. Underneath the sheet the mirror is secured to the frame with an adhesive. It's pliable but not silicone based and comes off in tiny pieces when I try to remove by hand. I'm going to try a couple solvents tonight and see if anything will melt it.
 
churchhaze said:
I'd imagine that anything toward the bottom of the walls won't really matter anyway unless you're trying to reflect far-red.
Click to expand...
I was wondering if it isn't actually better to put more diffuse reflective material towards the bottom. That would scatter some of the light back up to the plants instead of straight on to the floor, stems and pots.

So highly direct reflective materials (like mirrors or silver mylar) on top and something diffuse lower down.

I have that in my grows now, just never measured if it actually works.
 
I swear on flat white latex paint with 20% added titanium oxide. It provides strong and diffuse reflection while its washable and water resistant. 1kg titanium oxide costs ~ 12$ and 5kg latex paint around 8$. I mix 1kg TO into 5liters. If necessary, I can paint it over. Has been well proven in my wooden cabinets.. The only downside for me is it does not reflect UVB but thats the same with plastics and mirrows. Apart of this it's the cheapest and most efficient method for me.
 
But as demonstrated above by the tests Rahz performed, flat white offers less reflection (in the direction of the plants) than more direct reflective materials like mirrors.

Why would't Mirrors reflect UV? The aluminium in mirrors is actually a really good reflector for the range of wavelengths below the PAR spectrum.
 
wietefras said:
I was wondering if it isn't actually better to put more diffuse reflective material towards the bottom. That would scatter some of the light back up to the plants instead of straight on to the floor, stems and pots.

So highly direct reflective materials (like mirrors or silver mylar) on top and something diffuse lower down.

I have that in my grows now, just never measured if it actually works.
Click to expand...

Now I'm considering painting the floor white, followed up with a coat of polyurethane.
 
wietefras said:
But as demonstrated above by the tests Rahz performed, flat white offers less reflection (in the direction of the plants) than more direct reflective materials like mirrors.

Why would't Mirrors reflect UV? The aluminium in mirrors is actually a really good reflector for the range of wavelengths below the PAR spectrum.
Click to expand...

Yeah, alu would but normal glass blocks uvb too. And instead to cover the wall with alu foil I will rather try to build my own reflectors to direct the light on the canopy and not waste it on the walls. I've an old adjust-a-wing laying around and will use the stucco sheets to built them.
I'm using a 3ft bulbs currently so I only have to "pull" the "wings" down further on the sides so that laterally emitted light falls into the reflector and is not unreflected lost on the walls.

I'm a fan of diffused light and believe it travels deeper into the canopy.
Most of the time I do SGROGs but without trellis(LST and some bambus sticks to support branches if needed) and use my light 12-16" above the canopy(because of the UVB bulb in the center). The wall area which gets light is pretty small usually only in early veg when the plants don't fill the space there is a much higher light loss.
But I agree, light which directly hits the mirrors in the upper half of that small wall area would directly bounce back in the same angle and would be still hit the upper half of the plant. Maybe I should try a row or two of the cheap glueable 6x 6" mirrors one can get for cheap from e3ay? But I don't know if they are glass mirrors or alu coated plastics.
Wait...?
Alu coated plastics...? ... could reflect UVB, lol!
I SHOULD give it a try!
 
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