LED Newbie

Hello all.
First off , I am not new to growing. I’ve been growing for almost 20 years now but finally have pushed myself to switch from HPS to LED due to heat issues in the summer and I think they have finally caught up technology/price wise and seem to most certainly be a better route. I am very happy with my purchase of SpiderFarm 4000 which is very similar to the HLG 550 v2. I use 2 of these in a 4x8 tent with Sunshine soil , R.O water and complete Advanced Nutrients line.

I have not purchased a light meter yet. Apogee MQ-200 was what I have in my cart just haven’t pulled the trigger. I’ve been testing the waters just running these bad boys at 40% in veg and they were loving it but recently started noticing some light green in center of leaves. I’m days away from flowering cycle and would like to correct anything I’m possibly doing wrong first. I have a network of buddies in this but I’m the first of us old heads to make the switch to LED.

I’ve read I should be using MAgExtra with LED and my R.O. My canopy is 24” below lights and seem to be filling out nice, the nodes are close together, getting bushy and minor curling in leaves but def some noticeable areas of curling. These things I never experienced with hps so I’m just assuming it’s due to light intensity but I figured it was best to get other opinions before I jump into flowering.


I hope I’ve provided enough information to help paint the picture. Thank you very much for any input.

I can't say u need Calmag just because u use LED lights

Tap or RO water?

Tap has lots of minerals in it and usually offsets the need for Calmag

RO, it's a must to add Calmag

My pH buffered soil runs I never add Calmag
My DWC RO water runs I always add Calmag from day one

BobThe420Builder said:

I can't say u need Calmag just because u use LED lights

Tap or RO water?

Tap has lots of minerals in it and usually offsets the need for Calmag

RO, it's a must to add Calmag

My pH buffered soil runs I never add Calmag
My DWC RO water runs I always add Calmag from day one

Click to expand...

I have a R.O system and somewhere I read I need to add Calmag or MAgExtra with the LED and a R.O. Sorry I tried relaying that in the main post.

Thank you for this input , I have MAgExtra in my current line but only ever used it once in a blue moon but I’ll certainly be going that route now. CalMag is a much cheaper option and I also have a gallon of that on the shelf. It kinda solidified one of my theories. I appreciate your help

For sure add Calmag or similar if yer using RO water

This is my first go-round, so take it for what it is worth (I have been reading a LOT on here though)... I have had 2 plants in organic soil vegging under a fissioning 120 qb for roughly 9 weeks. I started slow without proper light, then allowed it to go root-bound, but I think the progress since is solid (despite the improved but still underpowered-for-the-space light). I'm using tap; I try to get in the 6.5 color range with ph down. Even so, a couple weeks back, my slightly older, otherwise healthy plant developed symptoms that looked exactly like the leaves in your 2nd photo. I was pretty sure I was starting to see it on the younger plant as well.

Like you, I was about 2' from the canopy (now closer, but I introduced the un-dimmed light too fast initially and had to back way off). I added epsom salts and have since seen this discoloration/fading problem clear up. I was using no added nutrients at the time. I used 1 tsp/gal epsom salts for the first try and started to see improvement. I used 1.5 tsp/gal for the next watering 3 days later (bumped it up because it appeared to be helping and it still seemed a reasonable amount from what I've tried to absorb here so far). I went back down to 1 tsp/gal for the 3rd and most recent watering. Not really sure if I should be backing off at this point or not, but leaning toward continuing at 1tsp/gal every other watering and seeing where it goes.

I had cal/mag in a shopping cart, but decided to just try epsom salts after reading more here. $9 for an 8 lb. bag, I think, and I am happy with the results.

I'm probably not someone who should be giving advice at this point, but I couldn't hold back on commenting when I saw the similarity to what I'd experienced. I have seen anecdotal claims of additional magnesium being required under the quantum boards, so here's my anecdotal story to go alongside the others.

Also, this is my first post - what better time than to say a first thank you to everyone dropping so much info. So... thank you, good folks! If I wind up with even moderate success, I'll owe it to the things I've picked up here. There has been much to learn about every facet of this project so far, and I am loving it, ha.