3500 color temp?

I just got a bridelux strip led light built using the 3500k color temp and was wondering if anybody here is using that temp with success? I'm not sure what it might be but some seedlings have been under the light for about a week and still look weak so I brought out my old trusty 150 hps and they seem better after just one day. I'm wondering of I should have went with the 3000k temp instead.

taproot said:

I just got a bridelux strip led light built using the 3500k color temp and was wondering if anybody here is using that temp with success?

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Only everyone. It sounds like they needed the heat, the HPS is another 150 watts and a lot of IR. What is the air temperature?

Nah, 3500k is fine. There is a very small difference between 3000k and 3500k, and I doubt that you would really differentiate between the two.

1212ham said:

Only everyone. It sounds like they needed the heat, the HPS is another 150 watts and a lot of IR. What is the air temperature?

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The room is about 78/80F

Aolelon said:

Nah, 3500k is fine. There is a very small difference between 3000k and 3500k, and I doubt that you would really differentiate between the two.

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Yea, my thoughts to I don't think it would be much different which is why I got the 3500K ones. I think the HPS put out more IR like the guy above was saying. It might be the little hempy pots I have them in as I noticed under the hps the perlite / vermiculite dried out faster so I might have to make some new ones and lower the drain hole more.

I used to bother a lot about the "color temp". Rather look at the spectrum output, if its fine in the spectrum output, it will be fine...

Porky101 said:

I used to bother a lot about the "color temp". Rather look at the spectrum output, if its fine in the spectrum output, it will be fine...

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I agree brother...I think it's a fluke and it has more to do with my medium being too saturated. I think I put too much vermiculite in the mix.

taproot said:

Yea, my thoughts to I don't think it would be much different which is why I got the 3500K ones. I think the HPS put out more IR like the guy above was saying. It might be the little hempy pots I have them in as I noticed under the hps the perlite / vermiculite dried out faster so I might have to make some new ones and lower the drain hole more.

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When using LEDs, because of the lack of IR in them, you need to run your room a bit hotter. In the low to mid 80s to account for leaf temps, if you had an IR temp gun, you could measure it. Usually this causes the plants to uptake extra calcium which is why you need to supplament calmag.

taproot said:

I agree brother...I think it's a fluke and it has more to do with my medium being too saturated. I think I put too much vermiculite in the mix.

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Could be, and I think the HPS could have helped dry things up a bit. What mix are you running? I ran about 30/70 coco/perlite.

My timber 3500 citizen works awesome! Custom made to fit my space. @RainDan

Aolelon said:

When using LEDs, because of the lack of IR in them, you need to run your room a bit hotter. In the low to mid 80s to account for leaf temps, if you had an IR temp gun, you could measure it. Usually this causes the plants to uptake extra calcium which is why you need to supplament calmag.

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If you can go upto 85f with hps and Co2 then can you go upto 95f with led and Co2?

taproot said:

Yea, my thoughts to I don't think it would be much different which is why I got the 3500K ones. I think the HPS put out more IR like the guy above was saying. It might be the little hempy pots I have them in as I noticed under the hps the perlite / vermiculite dried out faster so I might have to make some new ones and lower the drain hole more.

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Be careful not to over water your seedlings!!!

I've found that my plants are happier when the room temps are in the mid 80's with my arrays.

Get 3000k if you like a little bit of stretch. Get 3500k if your grow space is quite tight.
The largest plants from my last pull gave me about 950g dry. It was under 3000k so it did hog a bit of space from the ones under 3500k. I'd say the plant under 3000k ended up about 10-20% stretchier/larger than the other plants only though

Have also a look on humidity. In veg with 85°F you need at least 70% RH to get healthy growth. Otherwise the VPD gets too high and you'll get issues like cal mag imballance or over fertilization. Slow growth and yellowing on the leafes would be the result. Below is a chart you can use from start to harvest.

Porky101 said:

If you can go upto 85f with hps and Co2 then can you go upto 95f with led and Co2?

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Nope! But up to 90°F would be probably okay. I would go for 85-86°F leaf temps with CO2 and 82-83°F without. The needed RH is already in a critical high range in the mid eighties. With lower RH/high VPD you need to lower the nutrient strength to avoid issues. Would be a balance act to keep the plants happy. But there is a rule of thumb. When VPD is 20% too high you need to lower the nutrient strength by 20%.

goofy81 said:

Get 3000k if you like a little bit of stretch. Get 3500k if your grow space is quite tight.
The largest plants from my last pull gave me about 950g dry. It was under 3000k so it did hog a bit of space from the ones under 3500k. I'd say the plant under 3000k ended up about 10-20% stretchier/larger than the other plants only though

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Yield same ?

Na variance of about 650-950
But the 950 plant was next to the wall which made it extra surprising!

But no matter which grow I do. The corner with the 3000k is always ends up about 5-10cm higher after a few weeks veg!

Randomblame said:

Have also a look on humidity. In veg with 85°F you need at least 70% RH to get healthy growth. Otherwise the VPD gets too high and you'll get issues like cal mag imballance or over fertilization. Slow growth and yellowing on the leafes would be the result. Below is a chart you can use from start to harvest.

View attachment 4200093

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High humidity is definitely fine in veg. I run 70-80% in veg as I struggle to go any lower unless my exhaust fan runs @250w.
But be careful with VPD charts as not all plants are the same. I mean look at the rainforests, and tropical countries pressure there would be extreme!

On a side note, during my entire flower phase my Rh is at 70% most of the time with maybe 1-10 rotted buds out of 1000s. Also haven't really observed any difference in trichomes when I used to be able to have it at 50-60% Rh. Having 4 ceiling fans does wonders!

Edit : Just in case different strains or experiences may vary

I try to keep my VPD under 1.6 kilopascals. Currently due too environmental issues my VPD has been at 1.7 for the past three days. Plants dont seem to mind, they look happy. But I will try lower it once I get more equipment!