Is there a Maximum "safe" ppfd??

[LostTribe]

I tried to search but in a hurry. I got a ppfd meter app and wow the fce4800 is hitting 1200 plus on the sides and 1100 in the middle area on a 3x3 dialed to about 90%. Is that too high? I havent noticed any issues other than feeling like I am getting a sunburn from peeking into the tent. Cheers! LT

 

[Chi13]

This video taught me more about lighting than anything I've read or seen. Go to 23-24 minutes to get your answer, but well worth watching the entire video.
Dr Bugbee talks about going close to 2000 PPFD, and that cannabis can handle a lot of intense light.
https://www.youtube.com/watch?v=ID9rE5JewVg

 

[troutman]

Make sure you have everything dialed in properly before going crazy with the lights. Even then go slowly.

 

[Chi13]

If you watch the whole video Bugbee says exactly what troutman says. You need everything else dialed in.
He also says you can push seedlings and cuttings with a lot of light as well, which is contrary to what most think (26:35mins)

 

[LostTribe]

Make sure you have everything dialed in properly before going crazy with the lights. Even then go slowly.

Had week 4 issue when I jumped up from 1.8 to 2.3ec with brown long ways stripping like boron and a couple burn through spots just a couple. Runoff was 4.5ec and 6.0ph. Got it back down to about 3ec ton of 1.8 ran through again next watering. I'm doing better and they arent really drying out first time I tried coco it was a total shit show now adding led so imagine I am doing decent considering all that.

 

[LostTribe]

This video taught me more about lighting than anything I've read or seen. Go to 23-24 minutes to get your answer, but well worth watching the entire video.
Dr Bugbee talks about going close to 2000 PPFD, and that cannabis can handle a lot of intense light.
https://www.youtube.com/watch?v=ID9rE5JewVg

I am finding that I have not stayed up to date whatsoever on the growing sciences. Great link!

 

[Mars Hydro Led]

I tried to search but in a hurry. I got a ppfd meter app and wow the fce4800 is hitting 1200 plus on the sides and 1100 in the middle area on a 3x3 dialed to about 90%. Is that too high? I havent noticed any issues other than feeling like I am getting a sunburn from peeking into the tent. Cheers! LT

Thanks for choosing our FCE-4800. What is the height you tested?

 

[Mars Hydro Led]

This video taught me more about lighting than anything I've read or seen. Go to 23-24 minutes to get your answer, but well worth watching the entire video.
Dr Bugbee talks about going close to 2000 PPFD, and that cannabis can handle a lot of intense light.
https://www.youtube.com/watch?v=ID9rE5JewVg

2000 PPFD is the optimal data. the most powerful light in market hardly can reach average 1500PPFD. still a long way to go.

 

[DARKSIDER]

My safe range is 600 ppfd and max out at 980 give or take after that my stardawgs dont seem to like it strange but true and i dont use co2 and i also use a full spectrum MQ 500 quantum meter one of the best things i bought considering ive guessed for a lot of years..

 

[flower~power]

Cannabis can “take” a lot of light , but guess what ? cannabis does not need “so much” light Too much is detrimental…

 

[Switcher56]

My safe range is 600 ppfd and max out at 980 give or take after that. and i dont use co2

Pretty much same here

 

[LostTribe]

Mars Hydro Led top of the plants like 15-20 in depending. Am I getting sun burned peeking in there? Probably need to stop peeking in.

Flower Power You are very correct. That link above is great.

They say that outdoors that ppfd can reach 2000 but he didnt say anything about growing at high elevation. The strength of the sun in the mountains is definitely much higher than avg. Used to get fried in the summer @12,000 feet.

Havent had any problems in bloom so leaving it at 90%. However, in veg I continue to have alot of problems. This is a 3500k hlg off brand readings were 600 a bit lower on the sides. I am a perpetual overwatering though. Some of them are also in need of up potting. I dont think the f13 likes its roots to be constricted.

 

[flower~power]

Also depends if it’s a sativa dominant or a hybrid or an Indica dominant…

 

[Muleskinner]

Make sure you have everything dialed in properly before going crazy with the lights. Even then go slowly.

this is what I've found too. Outdoor light, even where I live at 43 degree north, is strong - 1500+ at noon here in the summer. However, it doesn't translate directly to indoor. Humidity tends to be higher outdoors, the roots are not bound in small containers. Also we blast them with 18 or 12 hours which is more hours of direct sun than most outdoor plots get.

I've found that if my soil is too hot, brighter light causes more uptake and they burn more. From what I've read, indoor growers face diminishing returns over 700-800 or so PPF, if you're not using CO2 the added yield with more light gets smaller....here's one example I found, I think from the Fluence website....

 

[LostTribe]

this is what I've found too. Outdoor light, even where I live at 43 degree north, is strong - 1500+ at noon here in the summer. However, it doesn't translate directly to indoor. Humidity tends to be higher outdoors, the roots are not bound in small containers. Also we blast them with 18 or 12 hours which is more hours of direct sun than most outdoor plots get.

I've found that if my soil is too hot, brighter light causes more uptake and they burn more. From what I've read, indoor growers face diminishing returns over 700-800 or so PPF, if you're not using CO2 the added yield with more light gets smaller....here's one example I found, I think from the Fluence website....

If you check out the video above he addresses this directly. Daily light integral is the measure of total light the plants can handle. DLI actually on that same ppfd app. I didnt even know what it was for until I watched the video. Might be a good idea to grab a couple new books to check out but I bet most are still very basic reads.

DLI he said was a better way to go about comparing measurements of light need/use

 

[Chi13]

I started off as an outdoor grower and live in Australia, at about 30 degrees S. Where I lived then (West of Sydney), the max temperature in summer got to 45 C (113 F), but often hovered around 35C (95F) most days. Plants thrived under these conditions, including seedlings, as long as you kept the water up. No idea what the PPFD was, but sun is extreme here. You are advised to wear protection, clothes and sunscreen from about 7AM throughout summer.

When I read stuff about indoor lighting and temperatures, it is often at odds with my outdoor experience. I mostly grew sativa's, or NLD, but did also grow a seed I found in a block of Lebanese blonde hash, and it also thrived outdoors in these conditions. I read that cannabis should not be grown above 28C? I read that you can't give seedlings too much light. I truly don't get it. Best cannabis in the world is grown in hot places with often extreme light, India, Thailand.

Plant's do behave differently under artificial light. For instance I often harvested the top buds first outside because they matured that way. The lower buds would take another week or two. The opposite occurs for my NLD types indoors. The bottom matures earlier. No idea why.

 

[Mars Hydro Led]

@LostTribe top of the plants like 15-20 in depending. Am I getting sun burned peeking in there? Probably need to stop peeking in.

We usually suggest 12-18 inches for flowering. the bar design light even can be in 8-10 inches.

 

[LostTribe]

@LostTribe top of the plants like 15-20 in depending. Am I getting sun burned peeking in there? Probably need to stop peeking in.

We usually suggest 12-18 inches for flowering. the bar design light even can be in 8-10 inches.

I have a tall one that is at 4 in so cant go any lower, but since you say that I will try to snap er down a bit more. Plants are looking great and really like the light so far. This new Cinderella I found is so thick I am worried about bud rot so also trying to get the RH down just a bit more. I was at 79F 60RH and today its at 77F 48RH.

This is from 7 days ago.

 

[LostTribe]

Its way thicker now and in person day 36. That was day 28.

 

[LostTribe]

Pics right above are 36 bloom. 79F 48RH at about 85-90%. Hope I didnt change it I cant remember have to look next time.

Much more even light distribution vs the qb's. The tall plant I bent over ended up smelling like sweet bazooka joe have to keep a nose on that one might be a reveg candidate after all.