Lighting New on this forum

[HemiSync]

Question,@BigSm0

Using the Cob lights what is damaging factor to the plant if the Cobs are to close, it isn't heat? What kind of radiation is the cause and can it be filtered out?
Photography was a hobby of mine and I used a lot of filters to defuse/correct the light coming onto the camera sensor (in this case your plant is the sensor)

• Neutral Density filters
• Polarizing filters

Can the same be used for the Cobs to filter out the damaging radiation?
Or even to change the color temperature (kelvin) as you can in Photography by using glass filters.

So my question is: What is the damaging factor/output of the cob lights?

Interesting concept, I had not ever thought about filtering them. The stress is light stress and here is an interesting piece on the subject that might give you more insight into what is actually happening.

 

[Raincheck]

Hi HemiSync,

Thanks for that link Interesting read! Within photography you can source all kinds of filters and a UV filter is one of them.
You have them in all kind of shapes (square or round) and made of glass.
As I have a small but totally controllable set-up I'm tempting to do a test and mount a UV filter on 1 Cob.
How I will do the test I don't know yet the obvious is to lower the UV filtered Cob.

Btw anyone who has some suggestions and/or advise be my guest

 

[Frenjamin Banklin]

Might be wrong but I think general consensus is that UVB and UVA are beneficial to the plant creating defenses and frosting up
I’m running a supplemental repti sun UV light in last two weeks in my plants with cobs.

 

[Raincheck]

Might be wrong but I think general consensus is that UVB and UVA are beneficial to the plant creating defenses and frosting up
I’m running a supplemental repti sun UV light in last two weeks in my plants with cobs.

Hi, Can I ask do you use this Reptile UVB UVA as one bulb or 2 separate bulbs and what is your verdict did you do a comparison with and without?

 

[Frenjamin Banklin]

I grabbed a cheap 2 pack of Reptisun 13w mini fluorescent bulbs. I have been running them in 8” reflectors very close to plant and 8” directly from one bud. And I run them 18/6 with my Cobs.
I have noticed absolutely no noticeable difference. In frost or density. But I’ll give it a few more grows to be sure. I run Cree 4K and 3k at around 100w per plant at 18” in flower. So maybe the cobs are good enough without. I can tell you that the Uv has not hurt the plants that’s for sure with my grow, so I wouldn’t try to eliminate it.
Getting to know a strains DLI requirement is just as important and nutrients from what I’ve experienced. The fun of running autos lends to the ability to run many strains. The downside if any is that light requirements within even the same strain but different phenotypes can be drastically different IMHO.

 

[HemiSync]

@Raincheck
I’ve got no experience with limiting or increasing UV lights. I believe @lunarman was doing some testing supplementing UVA/UVB but I don’t think they were being left on for extended periods, but I could be wrong, this was last year. Hopefully, he will jump in and correct me. :smoking:

Way too much Super Skunk tonight.

 

[Raincheck]

...

 

[Mizzo81]

Looking really good in there

 

[Raincheck]

Just planted a Blumat digital tensiometer,

I should have 2 more but can't find them after demolishing my big grow room, that's where I used them for years!
For me it was dead handy a good indicator of what was going on even now as lifting a pot is difficult to feel the weight.
Between 90 - 120 mbar was perfect but have a new set-up smaller pots, different lights and hardly no heat.
Time will tell...

How does a tensiometer work?
The soil moisture can easily be measured via suction pressure. This tension arises because plants,
absorb water from the soil against the suction power of the soil. With a tensiometer you measure the
suction force in which the water in the soil is retained. Because the suction force causes
underpressure in the tube of the meter, you can read the voltage from the display. This number
represents the minimum suction force that the roots must exert to absorb water from the ground.

Grtx Rain

 

[Raincheck]

Still a few weeks to go,

I can only compare this run with my old set-up but it's comparing apples to oranges (or any other fruit):

• Auto flower vs Photo's
• Hps vs Cobs

As I see it now the flower development is a bit attenuate, diaphanous, sheer, slender, slim, spare, twiggy and weedy .
But hey it's my first run and already know i have to make a few adjustments regarding:

• Light intensity (Cobs to close)
• Day/night cycle (20/4 hrs to 18/6 hrs)
• Water management (to little/dry)

Grtx Rain