Greenhouse Cover: high transmission vs diffusion?

GET MO

Registered Med User

Veteran

• Mar 14, 2014

• #1

I just bought some clear greenhouse plastic with high light transmission. Then I got to researching and I found some other stuff that's 88% light transmission and 55% light diffusion. how important is diffusion for growing cannabis and would loosing 12% transmission be worth it for the 55% gain in diffusion?

Another idea I was thinking of was getting a smaller amount of the diffused woven stuff and cutting strips to equally spread over the greenhouse, maybe causing some diffusion as well as having clear open spots... Suggestions/experience?

 

megayields

Grower of Connoisseur herb's.

ICMag Donor

Veteran

• Mar 14, 2014

• #2

I bought the high diffusive covering for our GH's, what I read was it help "spread" the light more evenly through out the whole GH....I haven't even unwrapped the 4 rolls we have yet, so I have no practical experience to draw from......(shrug) I am hoping it will work well.

Good luck to you as well!

 

aridbud

automeister

ICMag Donor

Veteran

• Mar 14, 2014

• #3

It depends on time of year, arc of the sun.

I've started out with clear, then covered w/ 60% shade cloth, and clear again after Labor Day. My setting....just a 8x10 green house...getting cann started for outdoor transplant, but mostly getting veg/herbs/perennials going. Mid Sept, brought back outdoor crop and matured around early Nov....but that being said....all were autoflowers with successive grows every 20 days.

 

GET MO

Registered Med User

Veteran

• Mar 14, 2014

• #4

I plan to use it for the next 2 months to flower plants. I will be light depping but need the greenhouse cover to protect from the elements.

 

GET MO

Registered Med User

Veteran

• Mar 16, 2014

• #5

wut do yall think of my other idea with the clear with strips of diffusion type?

 

Rainmaker

Member

• Mar 22, 2014

• #6

Best bet is to go with the higher diffusion/lower transmission option...the woven poly...it's what the industry is moving towards. It is what I have gone with in all of my recent GH builds and have been very pleased with it. Here in NorCal...the sun can be very intense in the heat of the summer...so the girls actually benefit from the decreased light transmission...which allows for better temperature control in the GH. The increased light diffusion of the woven poly actually amplifies any light on a cloudy..or lower light day.

 

Dkgrower

Active member

Veteran

• Apr 11, 2014

• #7

ÈDIT TO NOTE

(Ditten think about the heavy sun you get in California I wish I had such problems for my region northern Europa we want all the light we can get)

Good points rainmaker

 

grow nerd

Active member

Veteran

• May 23, 2014

• #8

Other than to protect against rain & wind, I never fully understood (diffusive) covers for outdoor growing. I'm coming from a strictly-indoor background, so please help me understand things for my first outdoor grow.

I have a PVC hoop house that I'm light dep'ing this summer, and I don't anticipate any rain until after harvest (northern CA). What do I gain from having a diffusive cover? Don't the plants like the intense sun (with proper nutrition)? Do the high diffusion / lower transmission covers cause more stretch between nodes from less intense light? I wonder, and am concerned about, getting less-than-productive levels of light during say, 6-9am, 6-8pm or such if I were to have the cover on at all times.

Is it easy/possible to get light bleaching from direct sunlight without, as you can get with a HID light too close to the tops of a plant indoors? I thought that was more from the heat put out from the bulb, rather than strictly intensity.

Right now as things stand, when the light dep cover is off during the day, it's a "regular" outdoor grow, not so much GH.

 

2

2 Legal Co

Active member

Veteran

• Jun 30, 2014

• #9

GN;
Here the concern is less about the Benefits of a 'cover', than keeping them enclosed and secured. Legalities you understand.

The reality of the situation is. If i can find a way to grow for free (or almost free), without spending a fortune on the GH, I'm in............

Free lumens and of course the extended growing season is good too. Last frost where I'm at is said to be JUNE 15th.......

But then, I'm in Colorado, so it's to be expected.

 

Pangea

Active member

Veteran

• Jun 30, 2014

• #10

I've read that 1% loss or gain in light transmission equate roughly to the same percent difference in final yield in traditional crops.

 

GET MO

Registered Med User

Veteran

• Jun 30, 2014

• #11

ive noticed plants with the continuous cover look more like indoor, perhaps from the light not being so intense. they seem to fill out better for my folks who had one covered and one strait sun. They said they like the cover better, so ima just run with their experience.

 

Z

zulu-

New member

• Aug 5, 2014

• #12

The GH industry is moving toward diffused (notice the lack of shadows in many modern greenhouses). ~70% diffused is the ideal, anything above that you start a trade-off in winter months where you get limited light intensity.

If you're getting 80% transmission, you'll do well -- to be honest, every greenhouse should be running a DLI meter so you know what you're getting on the daily (can automate your irrigation accordingly).

There are materials that get 90%+ transmission with 70% diffusion coming into the market, a bit pricey though.

 

armedoldhippy

Well-known member

Veteran

• Aug 5, 2014

• #13

the higher diffusion coverings I see look like they would be more stealthy if you are in an unfriendly locale. let about as much light in, but not nearly as easy to see through if used on a greenhouse side/roof.

 

stoned-trout

if it smells like fish

Veteran

• Aug 5, 2014

• #14

woven poly rules...farmtek

 

P

Player2

Member

• Aug 5, 2014

• #15

I don't know what your budget is, but this stuff rules.
http://www.palramamericas.com/Products/Corrugated-Sheets/DynaGlas-Family/DynaGlas-Plus/

$$$$$ and not stocked at any local hardware type places.

It is strange being in a greenhouse done up with that stuff, structure painted matte white and everything else orca film covered. No shade. Makes the plants shade avoidance mechanism go haywire. It is bright from everywhere. Not like nature.

It really traps heat, so plan your ventilation well.

It works.

I wanted to experiment with "red mulch" plastic on the floors & pots to really change the shade avoidance game. Didn't have the time, then I moved.

 

Pangea

Active member

Veteran

• Aug 5, 2014

• #16

The Dynaglas has three grades available; Plus, Solarsoft 90, and SolarSoft 85.

I'm unsure if the benefits of diffusion make up for the loss of 5-7% of transmission. I lean to the middle, SolarSoft 90 with 40%diffusion and 90%transmission.

 

Z

zulu-

New member

• Aug 9, 2014

• #17

Player2 said:

I don't know what your budget is, but this stuff rules.
http://www.palramamericas.com/Products/Corrugated-Sheets/DynaGlas-Family/DynaGlas-Plus/

$$$$$ and not stocked at any local hardware type places.

It is strange being in a greenhouse done up with that stuff, structure painted matte white and everything else orca film covered. No shade. Makes the plants shade avoidance mechanism go haywire. It is bright from everywhere. Not like nature.

It really traps heat, so plan your ventilation well.

It works.

I wanted to experiment with "red mulch" plastic on the floors & pots to really change the shade avoidance game. Didn't have the time, then I moved.

Click to expand...

"Hundreds of sq.ft. installed over the course of nearly 30 years"

I hope that's a typo.