Seedling Too Close To Led Lights?

[Hastings]

Here is the growing environment:

Temperature: 74 degrees F
Humidity: 45%
Growing Medium: Pro-mix HP
Fertilizer: None yet
Air Circulation: Indirect intermittent fan breeze
Lighting: DIY 4 foot long galvanized pipe duct with 10 LED 13W ecosmart bulbs with covers removed + 8 red/blue 6W grow bulbs. Distance of plants from light is about 16 to 18 inches.

This is the worst of them. It happened literally within 24 hours. Leaf isn't brown or yellow yet although I expect that soon, just the outer half of the leaves dry feeling and dark with curled up edges and tips. Looks like light burn to me, but I'm a bit surprised considering it's just cheap LEDs! Thoughts?

 

[MW7945]

At that distance, not likely. Probably more of an issue with the soil

 

[Monster762]

Here is the growing environment:

Temperature: 74 degrees F
Humidity: 45%
Growing Medium: Pro-mix HP
Fertilizer: None yet
Air Circulation: Indirect intermittent fan breeze
Lighting: DIY 4 foot long galvanized pipe duct with 10 LED 13W ecosmart bulbs with covers removed + 8 red/blue 6W grow bulbs. Distance of plants from light is about 16 to 18 inches.

This is the worst of them. It happened literally within 24 hours. Leaf isn't brown or yellow yet although I expect that soon, just the outer half of the leaves dry feeling and dark with curled up edges and tips. Looks like light burn to me, but I'm a bit surprised considering it's just cheap LEDs! Thoughts?

First up humidity. 60-70 I can’t really give you any opinion on the light but led panels I start 24-30 inches. Try not to get any water on leaves under the led. Pull em out for half hour or so if you want to spray. And you shouldn’t need nutes yet.

My guess would be the humidity by the dry curl.

 

[Hastings]

First up humidity. 60-70 I can’t really give you any opinion on the light but led panels I start 24-30 inches. Try not to get any water on leaves under the led. Pull em out for half hour or so if you want to spray. And you shouldn’t need nutes yet.

My guess would be the humidity by the dry curl.

I might be able to get the humidity up to 55% at most, and I already backed off the lights another 8" or so. I'll see if all that helps. I forgot to mention that the pH of the tap water I use for watering here is 8.2 and it's the first time I use the pro-mix which is pre-buffered to 6.5 to adjust for the acidity of the peat in the mix. City water here is also sanitized with chloramine if that makes any difference.

 

[MW7945]

Shouldn't realistically be a humidity issue, I start mine around that humidity typically.

Can try to run a humidifier in there and see if it helps I guess.

 

[TerpyTyrone]

Chlorine kills nutes. Aerate the water for 24 hr before using it. I dont like those paper pots either. They disintegrate..

 

[Hastings]

Chlorine kills nutes. Aerate the water for 24 hr before using it. I dont like those paper pots either. They disintegrate..

Sadly it's not dissolved chlorine, but chloramine which does not evaporate out of the water with aeration. It can of course be neutralized with sulfur dioxide, but with the side effects of slightly lowering pH (which might be a good thing in my case), and additional salts - which is obviously not good. I should mention that adult plants and seedlings prior to this DIY light setup seemed to do just fine with the city tap water here.

Those are 4" clay pots, because I ran out of 4" plastic pots which most of my seedlings are in. I hate clay pots because they dry out so darn quickly!

 

[TerpyTyrone]

Sadly it's not dissolved chlorine, but chloramine which does not evaporate out of the water with aeration. It can of course be neutralized with sulfur dioxide, but with the side effects of slightly lowering pH (which might be a good thing in my case), and additional salts - which is obviously not good. I should mention that adult plants and seedlings prior to this DIY light setup seemed to do just fine with the city tap water here.

Those are 4" clay pots, because I ran out of 4" plastic pots which most of my seedlings are in. I hate clay pots because they dry out so darn quickly!

Is the chloramine pretty standard? I was using RO from the store until I started using 5 gallons every 2 days.. The cloth pots are great for an overlover like moi! I get a kick out of misting them and hand feeding. Not to mention I plan to switch to an autofeed righr I,to them using a fountain pump and 1 minute intervals. It doesnt seem very difficult.

 

[Rootbound]

Most promix dont have any nutrients. I start my seeds in promix hp feeding them .8 ec(400 ppm). They might be hungry...

 

[Hastings]

Most promix dont have any nutrients. I start my seeds in promix hp feeding them .8 ec(400 ppm). They might be hungry...

Well the soil does have mycorrhizae at least! *kidding*

I had planned on feeding them once their growth slowed and perhaps bottom cotyledons were starting to lighten in color. The cotyledons still look as good as the day they opened, and the fact this happened so suddenly within 24 to 48 hours perplexes me. Only two out of a dozen seedlings were severely affected like that - some not at all (yet) and they are just as far if not further along. They all looked great until just a couple days ago.

The leaves that were affected have now turned necrotic and are shriveling up. The new leaves (second set) emerging still look okay. I turned down the temperature to about 71 degrees, backed up the lighting a few inches, and now have the relative humidity at around 50%. I think I'd like to see what happens to these emerging leaves first before I mess with it more, but in a few days as a last resort I might give them a mild 300ppm lunch. That shouldn't shock them even in their current weakened state (I think?).

 

[MissBotany]

All three of my white widow leaves did that I’m the very beginning. All the new growth is healthy now. My two cents, I would just wait for healthy new growth. If the new growth continues to “shrivel up” then I’d be concerned.

 

[Hastings]

All three of my white widow leaves did that I’m the very beginning. All the new growth is healthy now. My two cents, I would just wait for healthy new growth. If the new growth continues to “shrivel up” then I’d be concerned.

Thanks for the vote of optimism! So far the new growth does look fine, but so did the first true leaves until they were opened completely.

I did some measuring. My tap water has a TDS of 69ppm, and I flushed the plants for watering time. The out reading for the first runoff (just under an equal volume water to soil) was a TDS of 155ppm! Turns out the first runoff from these plants has less crap in it than a lot of people's drinking water! Flushing was done after saturating the soil about half an hour before.

So what I did just awhile ago was first bring down the pH of my 8.2 tap water to about 6.5 pH, then I added enough nutes to make about a 370 ppm solution which I again flushed my plants with. The first runoff from that tested 7.2 pH and only 252 pmm. Very interesting....

 

[MissBotany]

Thanks for the vote of optimism! So far the new growth does look fine, but so did the first true leaves until they were opened completely.

I did some measuring. My tap water has a TDS of 69ppm, and I flushed the plants for watering time. The out reading for the first runoff (just under an equal volume water to soil) was a TDS of 155ppm! Turns out the first runoff from these plants has less crap in it than a lot of people's drinking water! Flushing was done after saturating the soil about half an hour before.

So what I did just awhile ago was first bring down the pH of my 8.2 tap water to about 6.5 pH, then I added enough nutes to make about a 370 ppm solution which I again flushed my plants with. The first runoff from that tested 7.2 pH and only 252 pmm. Very interesting....

Let me preface by saying I am new to growing to cannabis but always add nutrients first then adjust pH. My nutrients (general hydroponics) make my water acidic. So if you’re adjusting pH first then adding nutes, chances are your pH is now lower than what you originally adjusted it to.

Also, not sure if run off is an accurate measure of pH. Might want to read some info about that...

 

[Hastings]

Let me preface by saying I am new to growing to cannabis but always add nutrients first then adjust pH. My nutrients (general hydroponics) make my water acidic. So if you’re adjusting pH first then adding nutes, chances are your pH is now lower than what you originally adjusted it to.

Also, not sure if run off is an accurate measure of pH. Might want to read some info about that...

You're right of course! I just measured the left over solution and it's a tad over pH 6. So that 300 ppm nutrients brought it down half a point.

 

[TerpyTyrone]

I have noticed gh flora series nites unstable. Everyday I would have to re ph what a pain in the ass!! I do I,d so ff tiger bloom and used that in place of the bloom part. Man what a difference!! Its stable! I had to add silica to bring it up. To 5.8

 

[Bicyclejuju1]

Here is the growing environment:

Temperature: 74 degrees F
Humidity: 45%
Growing Medium: Pro-mix HP
Fertilizer: None yet
Air Circulation: Indirect intermittent fan breeze
Lighting: DIY 4 foot long galvanized pipe duct with 10 LED 13W ecosmart bulbs with covers removed + 8 red/blue 6W grow bulbs. Distance of plants from light is about 16 to 18 inches.

This is the worst of them. It happened literally within 24 hours. Leaf isn't brown or yellow yet although I expect that soon, just the outer half of the leaves dry feeling and dark with curled up edges and tips. Looks like light burn to me, but I'm a bit surprised considering it's just cheap LEDs! Thoughts?

Did you ever figure it out? I'm having a similar problem

 

[RonnieB2nd]

Here is the growing environment:

Temperature: 74 degrees F
Humidity: 45%
Growing Medium: Pro-mix HP
Fertilizer: None yet
Air Circulation: Indirect intermittent fan breeze
Lighting: DIY 4 foot long galvanized pipe duct with 10 LED 13W ecosmart bulbs with covers removed + 8 red/blue 6W grow bulbs. Distance of plants from light is about 16 to 18 inches.

This is the worst of them. It happened literally within 24 hours. Leaf isn't brown or yellow yet although I expect that soon, just the outer half of the leaves dry feeling and dark with curled up edges and tips. Looks like light burn to me, but I'm a bit surprised considering it's just cheap LEDs! Thoughts?

Did you feed them? Looks like mild nutrients burn. Or over watering. Only give sprouts 2 cups every 2-3 days

 

[Bicyclejuju1]

Did you feed them? Looks like mild nutrients burn. Or over watering. Only give sprouts 2 cups every 2-3 days

I haven't fed them anything. I've only watered them once since they popped. I wait till containers are very light and soil dry.