HLG 260QB - Ideal Seedling Distance?

Troubleshooting my second grow. My first didn't go so well. Temps, humidity, and everything else seem ideal, but growth was stunted. Watering based on weight - 2-3 times over the course of 2 weeks - but never fully developed second set of true leaves. First round I thought maybe it was water, so I started PHing. PPM in my water isn't great but not horrible - ~175. I'm in FF Happy Frog with 25% perilite mixed in.

Unfortunately, I'm seeing the exact same problem with my second grow. Sprouts do just fine. Seedlings pop early. Within ~36 hours of emerging they're stretching. And then they just slow down. They don't stop, and their color isn't bad. Leaves just stop growing. I'm working with Mephisto genetics (a few different strains -- all autos of course), but all I've tried so far (4 strains) are having the same problems.

I'm starting to think maybe it's LED distance. I have my HLG 260 V1 at about 30". Dimmed all the way down - which should be around 15W/sq. ft based on vendor spec. I'm starting to wonder if it's a light issue. In both grows, I've had some stretching happening. Can anyone else who does seed->flower with these lights give me some insights on ideal distances for younger plants?

Thanks in advance.

Are you dimming using A-type driver, screw driver in a hole on the driver? It will dim down much more than 50% sounds like you might be under lit. You need either a powermeter to find out your real watts or a light meter finding your real light levels. Stretchy seedlings with nice normal colors sounds like too little light. Allthough with autos and hlg260 its hard tto understand how, should be enough.
Also if really 15w per squarefoot, that might be too much... Its hard to say.

In general overlighting and overwatering are the most common beginner errors. 2-3 times in 2 weeks sounds like a lot, depending on pot size and amount of water.

Also, photos of all your plants would be good

Rocket Soul said:

Are you dimming using A-type driver, screw driver in a hole on the driver? It will dim down much more than 50% sounds like you might be under lit. You need either a powermeter to find out your real watts or a light meter finding your real light levels. Stretchy seedlings with nice normal colors sounds like too little light. Allthough with autos and hlg260 its hard tto understand how, should be enough.
Also if really 15w per squarefoot, that might be too much... Its hard to say.

In general overlighting and overwatering are the most common beginner errors. 2-3 times in 2 weeks sounds like a lot, depending on pot size and amount of water.

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Thanks for the insights, @Rocket Soul

I do indeed have the A-type (240H C2100A) driver. My configuration for 30" was to have the dimness set all the way down. To your point, I may be wrong on the output/sqft. I was going by their listing on site which indicates dimmable 135-285W. Assuming the lowest is 135, I divided that out (Which is actually 16.9, I guess I was using 120) Sounds like a lux meter is in my near future, as I can only guess what's actually hitting these things right now. Or maybe I'll just snag a cheap CFL lamp which would probably be cheaper.

I'm attaching a few pictures. Going in, I was paranoid about over watering. Maybe I've been doing it anyway, but my strategy in both grows was to water both solo cups (drainage added + mixed with 25% perilite) to beginnings of runoff, then drop seed in, cover, and leave for a few days.

I had sprouts ~60 hours later in both cases. Afterward, I did not water. Just kept light going at aforementioned configuration and activated exhaust + humidifier. (Both low. Humidifer enough to keep ~55% RH and exhaust on minimum for the sake of circulation since I'm in a closet - average temps around 75 with lows at 68 and highs at 79)

For the first grow, I didn't water any until 6 days after sprout aside from a couple mistings. Cups were nice and light, and I thought that's maybe why they stopped growing. At that point, I gave 'em 2 TBSP PH'd water.

5 days later I gave another 3 TBSP of PH'd (6.3) water. They were still growing, but the progress seemed stunted compared to other peoples' autos in the same timeframe. Sprouts were coming up fast, true leaves nice by day 3 or so. Then they just kind of stopped.

I ended up deprioritizing them and starting a couple more, at which point I just observed what they did with no additional meddling. I wish I had recorded the date, but it was a little over a week ago (~2.5 weeks since sprout) when I noticed they were getting yellow and tossed them. Roots had been growing but never went very far down into cup. (A few towards the top had gone lateral to cup's edge - but not a lot of growth for 2.5 weeks) Those second true leaves had formed but were growing by maybe 5% per day whereas other grow diaries seemed to show them appearing in full overnight.

This grow is still pretty young - 6 days today. She's doing okay and maybe I'm inferring a problem where there isn't one yet. The sudden lull is the same as my first run; which makes me think I'm doing something fundamentally wrong. For what it's worth, I had been assuming water was somehow my problem up to this point, but trying to think outside that box. I gave her 3 TBSP PH'd (6.3) water with a little (1/2 vendor recommended dose) myco on day 3. Soil was bone dry 1.5 inches down. Haven't given her any more since then.

pic 1: Grow 1, day 2
pic 2: Grow 1, day 5
pic 3: Grow 2, day 2
pic 4: Grow 2, day 6

Sorry, i thought you watered much more. That growth is slowish but they dont move that much in the start. Does it not develop any further from here? Damned if knew...

Rocket Soul said:

Sorry, i thought you watered much more. That growth is slowish but they dont move that much in the start. Does it not develop any further from here? Damned if knew...

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No worries - @Rocket Soul, thank you for reading my wall of text and sharing your wisdom.

Early on, my first grow was definitely overwatered. I didn't have exhaust running, so that mess I made of the soil before germinating my seeds in it stayed moist for a long time. I am running exhaust full time this go-round and the soil seems to be drying up much quicker - or at least at a healthy pace.

The last round didn't really go any further. It's probably too early to say with this one. I am going to let her go and see what she does. Thinking about your remarks, I decided to grab a lux meter app. I'm finding some weird results -- or at least they don't seem consistent with what another user on a comparable HLG light found.

At 24" from seedling on dimmest setting, my max reading is around 1400 lux.
At 24" from seedling on full blast, and I'm reading about 5400 lux.

Comparing with another user's thread and a similar board (QB260 - not sure if V1, V2 or rspec though), I'm seeing substantially lower lux readings. His walls aren't reflective, so I can't blame the crappy interior of my tent. Worse, I can't get to that 46000 lux they mentioned without having the camera much closer (A couple inches) and on max. I'm seeing higher lux readings a couple inches away from a CFL in a lamp in my room.

This is a well rated iphone app, and I've tried on a couple different devices to rule out any oddities there. Ever heard of anything like this?

At a glance, the light seems bright as can be, but wondering if maybe there isn't an issue given these readings.

You keep mentioning pH'ed water but how are you measuring pH? My guess is cheap unreliable meter or broken meter. If using a cheap meter throw it in the trash(maybe stomp it a couple times too for being a piece of junk) these strips are miles better until you can get a nicer meter since those cheap Amazon ones aren't worth a fuck. The PPM meters surprisingly aren't that bad but don't ever trust a cheap pH meter. Maybe in the near future there will be good cheap pH meters but we're unfortunately still not there.

[ZooWeeMaMa] said:

You keep mentioning pH'ed water but how are you measuring pH? My guess is cheap unreliable meter or broken meter...

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I have a blue labs pen. It's about 3 weeks old, and I've been comparing its results with some cheaper drops I got before I realized how difficult it would be to calibrate with the drops.

As an update, I did grab another lux meter app. Seeing better numbers from that. At 16" on dimmest, I'm getting around 6800 lux.

olegren said:

I have a blue labs pen. It's about 3 weeks old, and I've been comparing its results with some cheaper drops I got before I realized how difficult it would be to calibrate with the drops.

As an update, I did grab another lux meter app. Seeing better numbers from that. At 16" on dimmest, I'm getting around 6800 lux.

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There's your answer then bub. That's way too low. For example, my t5 set-up for seedlings is 30,000 lux at 8 inches where I keep it and they love it. Currently I have everyone with about 50k even spread of LED. If you want to adjust your driver plug into a watt reader first then adjust it so you know exactly where it's at since those things cranked all the way down is actually around 80w and the screw adjusts a lot just by little touches so you really have to have a meter telling you where it's at. Luckily they're only ten bucks. Killowatt meter...

You want your lux at or over 15k. Personally i have a dedicated lux meter... they are cheap and worth having in my opinion.

Even if your phone isn't the greatest a lux meter app should work just as good as some cheap meter since all phones have lux meters in them that's how they adjust brightness when using auto brightness function. If you have a Samsung that's not Verizon or Sprint I think then you can just dial *#060#* or something like that to pull it up. Look it up....

Thanks for the insights, fellas. I am ok with the phone apps. Beats not having anything else, and just seeing consistency between readings on a couple apps gives a nice ballpark.

Im unable to get a reading beyond 20k with either app on my QB at max which is making me wonder if I don’t have a problematic unit. I can’t even get that high without getting a few inches away. Gonna reach out to HLG to see if they can help me troubleshoot.

olegren said:

Thanks for the insights, fellas. I am ok with the phone apps. Beats not having anything else, and just seeing consistency between readings on a couple apps gives a nice ballpark.

Im unable to get a reading beyond 20k with either app on my QB at max which is making me wonder if I don’t have a problematic unit. I can’t even get that high without getting a few inches away. Gonna reach out to HLG to see if they can help me troubleshoot.

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That could be the case bro. To give a point of reference my HLG qb288 V2 driven at only 115w reads at 269k an inch away and 50k at 19".

Figured I'd update... my cheapie Lux meter arrived and gave much better results.

I was freaked out because both my apps (on two different iphones) were giving really inferior readings for my QB -- but decent readings for other random bulbs. According to those, I was pulling more from a CFL a couple inches away than I could my 260 on full blast.

Anyway, proper lux meter proved the light is working fine. I have heard Samsung devices are quite superior at detecting lux, and that certainly seems to be the case based on my experience with the iphone apps.

Thanks again for the help.

olegren said:

Figured I'd update... my cheapie Lux meter arrived and gave much better results.

I was freaked out because both my apps (on two different iphones) were giving really inferior readings for my QB -- but decent readings for other random bulbs. According to those, I was pulling more from a CFL a couple inches away than I could my 260 on full blast.

Anyway, proper lux meter proved the light is working fine. I have heard Samsung devices are quite superior at detecting lux, and that certainly seems to be the case based on my experience with the iphone apps.

Thanks again for the help.

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Yeah that's the problem. That's why I'll always use Android. iPhones are good for old people that only wanna use their phones for calling and a little internet usage.

olegren said:

Figured I'd update... my cheapie Lux meter arrived and gave much better results.

I was freaked out because both my apps (on two different iphones) were giving really inferior readings for my QB -- but decent readings for other random bulbs. According to those, I was pulling more from a CFL a couple inches away than I could my 260 on full blast.

Anyway, proper lux meter proved the light is working fine. I have heard Samsung devices are quite superior at detecting lux, and that certainly seems to be the case based on my experience with the iphone apps.

Thanks again for the help.

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Glad you got that sorted out!

Hey, I know this is a little old, but how are those seedlings doing now? I habe an hlg 260 v2 rspec with a mephisto fugue state autoflower seedling in my tent and after reading this i just lowered the lights and got the lux to 15k lol. Where did you settle on leaving the light to fox the problem? Thank you