Running two lights but one for 6 hours during flowering?

Hi guys,

Currently running a 600w HPS in a 1.20m by 1.20 tent, in first week of flower. I have a 315W LEC I'm not currently using, can I add this to the tent for say 6 hours? Or could it stress the plants out losing light intensity halfway through light period? Reasoning behind 6 hours is electric bills are getting a bit silly.

How much approximately would it increase my yield by on 6 hours, and also on 12 hours? I know it depends on a lot but I'm talking generally.

I'm growing 10 pineapple chunk and 5 gorrilla zkittles in this tent.

Thanks

Yes, this will aid in the bud production.

Yeah sure use it like KGP said, lighter in flower the better, in those 12 hours it needs AS MUCH LIGHT AS POSSIBLE

I dont think it will be worth the increased yields if power cost is prohibitive, the gains will be marginal

saintmetalhead said:

Yeah sure use it like KGP said, lighter in flower the better, in those 12 hours it needs AS MUCH LIGHT AS POSSIBLE

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Sorry to disagree, but it's well known that too much light will cause problems. More of everything is not always better.

1212ham said:

Sorry to disagree, but it's well known that too much light will cause problems. More of everything is not always better.

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yes a 600w Hps gives out enough light for that area, at some point the CO2 intake limits. Which would only get worse with another 315w heating up the leaves.

However, if your tent is high enough you could combine both in a vertical approach

TurboTokes said:

I dont think it will be worth the increased yields if power cost is prohibitive, the gains will be marginal

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That I can agree with for sure if power is the main issue . That’s o e reason I went to led panels saved a bit of money . Sorry about that.

1212ham said:

Sorry to disagree, but it's well known that too much light will cause problems. More of everything is not always better.

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Yeah I can see that with certain lights for sure cause of the heat and stress that can cause etc I think it’s situational. But adding more light usually if not always causes more heat.

saintmetalhead said:

Yeah I can see that with certain lights for sure cause of the heat and stress that can cause etc I think it’s situational. But adding more light usually if not always causes more heat.

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Adding more light does not always add more heat. HPS vs high efficiency LED is the classic example, more light with less heat.

It is quite possible to have too much light WITHOUT too much heat, this is well known among many LED growers.
It's all about leaf temperature. Under HID, IR raises leaf temperature a few degrees ABOVE air temperature. Under LED, leaf temperature is typically 1 degree LOWER than air temperature due to transpiration. For that reason, the optimum air temperature is around 29C with LED.

1212ham said:

Adding more light does not always add more heat. HPS vs high efficiency LED is the classic example, more light with less heat.

It is quite possible to have too much light WITHOUT too much heat, this is well known among many LED growers.
It's all about leaf temperature. Under HID, IR raises leaf temperature a few degrees ABOVE air temperature. Under LED, leaf temperature is typically 1 degree LOWER than air temperature due to transpiration. For that reason, the optimum air temperature is around 29C with LED.

Growers Edge | Hawthorne Gardening Company

Shop for Growers Edge Products.

www.just4growers.com

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yeah and i myself do grow LED and find that your sweet spot is right on. i guess ive personally never had any negative effects from too much light. but i can see it being a thing with small spaces and few plants. thanks for the info bro.

Or maybe you could install Far Red and then have your HPS lights for one hour longer on. Or UVA/UVB for more resin production. Actually that's something you would put on only for some time.

Run the light for the next two weeks of stretch and give her a little extra feed. Stretch is a big growth spurt and the extra light, and CO2, can make a big difference. Once stretch is over the 600 will do to the end with good results.

Power ain't cheap here either.

Thanks for replies guys. I dont mind paying the power as long as I get a good yield back, but sounds 600 hps is sufficient. I've just harvested another tent which had 2 600 hps in but 4 weeks before harvest I added a 3rd 600 and found a few plants turning hermie, and having additional bud growth which made buds look a bit weird. Still turned out great but I think I had the 3rd light too close, may of turned out better if it was further away. It was in a 8 x 4 tent

fumaganja said:

Thanks for replies guys. I dont mind paying the power as long as I get a good yield back, but sounds 600 hps is sufficient. I've just harvested another tent which had 2 600 hps in but 4 weeks before harvest I added a 3rd 600 and found a few plants turning hermie, and having additional bud growth which made buds look a bit weird. Still turned out great but I think I had the 3rd light too close, may of turned out better if it was further away. It was in a 8 x 4 tent

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I would think that 3 x 600s spaced evenly along the 8' length would be just about perfect for an 8x4. I plan to build an 8x4 flower room as an addition to my current grow room and power it with 2 x 600W on my light rail. Was going to use my 1000W but get 50% more light for 20% more power using the 2 - 600s. Light rail only uses 9W.

Too much light can cause the buds to foxtail and grow weird tail-like buds sticking out of the main colas nearest the light. Some strains seem more prone to that.

OldMedUser said:

I would think that 3 x 600s spaced evenly along the 8' length would be just about perfect for an 8x4. I plan to build an 8x4 flower room as an addition to my current grow room and power it with 2 x 600W on my light rail. Was going to use my 1000W but get 50% more light for 20% more power using the 2 - 600s. Light rail only uses 9W.

Too much light can cause the buds to foxtail and grow weird tail-like buds sticking out of the main colas nearest the light. Some strains seem more prone to that.

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Thats true and more even light spread. Yeh that exactly what happened to mine. They started fox tailing and new white pistills which ended up changing the shape of the bud. I think they may of been what caused it to hermie too as there was nanners in the buds.

Are the rails good? I've never used one. It moves the lights constantly no?

fumaganja said:

Thats true and more even light spread. Yeh that exactly what happened to mine. They started fox tailing and new white pistills which ended up changing the shape of the bud. I think they may of been what caused it to hermie too as there was nanners in the buds.

Are the rails good? I've never used one. It moves the lights constantly no?

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I got the Light Rail 4.0 with a 6'6" rail. Made in Colorado and works real nice. Can adjust the speed and the delay at each end. Mostly only running about 2' each way in my current grow room when I use it but not running it now. I bought two ultra light shorty batwing style reflectors when I got my 600W ballasts and lights and am going to join them back to back. Just 4 pop rivets on each so will drill those out and a strip of tin to join them together with either new pop rivets or small bolts. I got a shop full of tools and parts so it's not a hard job.

The rail is about $300US but you can cover almost twice the area with the same amount of light so save huge on power. Quicker payback than investing in LED lights for me.

Don't even have to add any wiring to my panel in the shop. There's a dedicated 15 amp line going to the water distiller downstairs that I'm going to clean up and sell for around $500 to buy the parts to build a custom RO unit that can deal with my dugout water. I just have to pull the big staples holding that line to the wall and it will reach right to where I need it in the new grow space. It will be just for the two lights and maybe a fan or two and the light rail power supply.

My 6" inline fan is dying so I just got an 8" fan to replace it thinking that I'll need extra power for two spaces but I ran that 6" at half speed all the time and it was more than enough so wishing I'd stuck with another 6" but oh well. This one has a built in speed controller matched to the motor and should last longer than me. lol

fumaganja said:

Are the rails good? I've never used one. It moves the lights constantly no?

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I use movers too. I like that they hit leaves from different angles as they move. Easy way to mount lights too.

Hey...with the 315 you'll be at 56 watts/sf which is a little high. I'd just go with the 600.
JD

Buy a 2nd cmh light and replace the 600w hps with it. Outlay, but will reduce overall running costs. 2 cmh lamps together in that area would do great. If I had the choice I'd use 2 cmh lights over 1 600w hps.

Fevs. said:

Buy a 2nd cmh light and replace the 600w hps with it. Outlay, but will reduce overall running costs. 2 cmh lamps together in that area would do great. If I had the choice I'd use 2 cmh lights over 1 600w hps.

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I just got 3 slightly used 600W digi ballasts, 4 - Hortilux SHPS lights and 3 hoods for $200. I'd love CMH and have a 400W Philips CMH that's great but find me some 315s for that price and I'll be all over them.