Sf4000 light burn

Hi guys, im on my 2nd autoflower grow with sf4000. I really seem to struggle with light burn. First grow i think I mistook it for fertilizer burn. This grow im sure it’s an issue. Im growing Gorilla glue and girl scout in a 5x5 tent, 3 gallon bags with HF soil, Jack’s 3,2,1. The water/nutes were ph 6.5 but the run off was 5.8-5.9 Anything over 70% intensity was a problem

Im plan on going with 5 gallon bags next grow hoping a larger root ball will supply more water and help. Do you think this is the issue. Any other ideas?

@Hellraiser or anyone lol


This could be a huge help.


I suggest you download the phonetone app for your smart phone and you can check your PPF at the canopy


@dirtydave I know your trying to help but there is a reason most experienced members avoid just stating something as simple as you did.

#1 if someone doesn’t know what DLI is it make no sence

#2 there is alot more to DLI then downloading the app and taking a reading.

Without an in depth knowledge it’s useless.

Providing the place for someone to learn like @Underthestairs has allows them to explore the topic and drives them to learn if they truly want.

@bonger read through that post and it will teach you how to measure light and how to dial in your lights appropriately, this able to be learned in a very short period of time. It will take experience and frankly a couple. Years to learn how to read plants but we are here to help as long as your investing the Time and energy.


Yeah too much light too early sounds like the problem. With that light you’d need less than 50% while in veg (even less with seedlings and small plants).


Thanks, that should help if I can figure it out :rofl:.

I’ll be honest, I was hoping someone with sf4000 would just chime in and say do this, this and this lol…

I’ll definitely DL that app and check that out… I figured out ph and ppm… so there’s that :rofl:

Thanks again


definitely taking that route, thanks for the info and reassurance :sunglasses:

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Thanks for looking out for me lol, great advice I always get on here. I’ll listen to anyone. Heck, we can just chat if you want lol

You sound like you have it going on. Im gonna try to figure it out. Time and effort i have lots of… sometimes braincells im short on. Thank you :blush:.


Thanks @Hellraiser

I thought I was good in veg… I was at 50% but the damn things shot up over night and got too close for veg. One never recovered. The 4 others came right back. Everything seemed to be going great up until about 10-11weeks. It just seemed like the leaves just started drying up and dieing. Even after I started flush which I think I started too early. I didn’t harvest until 14 weeks and tbh it looked like the buds could still grow, but leaves were dieing. I still think I’m gonna use 5 gallon bags

I think I got a decent harvest, about 3-4oz per plant. But I think the GSC could have done better. Buds were airy and didn’t show trichromes like gorilla. But sticky asf. Everything is curing right now.

I’m getting 20 Gorilla and 20 Northern lights coming Tuesday from ILGM

Thanks for your help as always :+1:

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Planning on 40% throughout veg. I used t5 until transplant. So there 8 or 10" when they go under sf4000


do autoflowers die at a certain age…? Mine seem to take extra long to mature and fill out

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@Hellraiser @Nicky @Underthestairs @dirtydave

Here’s an example. This is a 14 week old GSC. Covered in milky trichromes and sticky, sticky, sticky but looks pretty much dead

But it started doing this at 10-11weeks but definitely wasn’t mature at that time


To much light, not perfect nutrients, your plant just starts to die at that point and if your not giving it ideal care it looks dead before it ripens.

Ps you’ll need a diffuser to use that app so do read all the way through my DLI thread


Thanks, nutrients have been a learning experience with room to grow. Im using jack’s, but a little unsure of changing the formula much. I thought it seemed like too much nitrogen

If you’ve seen jack’s finish… 7 15 30… I don’t like the homoginazation (lol sp?) Mixing a gallon at a time seems impossible to get the same balance each scoop. It’s powdery with the nitrogen sulphate balls mixed in sporadically


so I shouldn’t be following this? Because I’m having the same problem. Same sf4000 lights at 50% about 2 feet above and its burning them


I just had a similar question crop up in my own grow. The pros (@Nicky being one of them) all suggested just using an MKP blend (0-52-34 or as close as you can get) instead of the Jack’s Bloom or Finish.

Something like this:

I found a brand at my local store called MOAB “bloom booster” but it’s just MKP with a different name.


I have ran my light at 18” and had no issues.
But anything closer than that will be an issue.
How far is your light away from your top canopy?


I find for me to remember the right way… I need to understand why it’s “the right way”


I have a 3 stage jacks feed scedule and so far this is how it goes:

Jacks 321 veg + boosted mag when running high DLI, keep in mind if you see calcium rust spots boost the cal nitrate but I haven’t had that problem let like some have.


Mkp booster mix (first 2 weeks of flower) 2/2.7/2/1.2

Flower mix 3.8/2.6/1.8


That’s exactly what I was following. My first early mistake was distance. I blinked and they one was 16" away. It never recovered

I never really got over 70% during flower without problems. I pretty much maintained distance except at the very end. I was a little closer than 15", but off to the side some. Distance is challenging in a tent. I have an 80" tent (that measures 78"). There’s a 1’ extension kit but its expensive and you still need a high ceiling. I did shorten the cables supplied with the light to get a couple more inches, but I’d be careful because it adds extra stress on the light frame

Good luck!! It’s a great light

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