First time grower, need help identifying the cause of leaf tip burn

Hello,
First time grower here, running into an issue with my Girl Scout Cookies leaf tips burning, and a few other things. Any help with this or advice would be greatly appreciated there is so much info out there it gets kinda overwhelming for someone that hasn’t grown anything.
Please see below for grow info:

All six are autoflower plants and are on day 20 when this pic was taken.

x2 Girl Scout Cookies (pic with the teal tab in the soil) These are the plants which are getting some kind of a burn on tips.

x2 Bruce Banner (pic with red tab in soil)
These two plants have droopy leaves.

x2 Gorilla Glue (pic with the dark blue tab in soil)
These two plants look like the leaves are kind of curling up and in.

Grow info

5x5 Mars Hydro Tent

Light Ts3000
32" from plant tops at 75%
ppfd 500-600 dli 45-53
Running 24/7

5 gallon fabric pots

Medium: 70% coco coir / 30% perilite. I also added about 15% ewc and the following dry amendments 3tb per gallon of 4-4-4 and 1tb per gallon 3-9-4.
Medium PH 6.8
I have not fed the plants any nuts at all other then what I premixed in medium. I have given them a aerated tea with bat guano(7-3-1), worm castings, molasses, alfalfa meal and kelp meal at 10 days and have another one ready for day 21.

Water: Tap water aerated for 24 hours and Ph 6.3 water temp 67f.
Watering: This is where I get confused, I have yet to water with any run of whatsoever. I could really use some guidance here my soil only dries out on top inch after 24 hours but still remains moist down lower. So far I have been watering every 24 hours with no run of.

Climate control Air Infiniti with 6" carbon filter
Temp 74f RH 67% VPD .9kpa
I have two fans going.

I just found out about VPD yesterday and corrected it with a humidifier up until yesterday my VPD was at 1.6kpa which I think is way to high from what I’m reading on the charts.

Anything you can point out that needs adjusting or correcting would be greatly appreciated.
I’m here to learn and not afraid of criticism.
Thanks in advance.






1 Like

I don’t see anything worrying. Plants look really nice.

I water a cup and a half of water per gallon of medium every other day or so. I give my plants a good soak (water to runoff) every week or so…

2 Likes

Me personally at this point would just make sure the leaves are not touching the soil and leaf tuck happy growing :v:

2 Likes

Agreed with @Vtbudz. Keep up what you’re doing, keep a fan going and don’t let the leaves lay on each other too much. They look good!

2 Likes

And welcome to the community!

2 Likes

Good call on adjusting VPD. If you can lower RH to 60% and raise temp maintaining your kPa you might see the plant grow taller. Nothing wrong with 67%RH and 74*F but if you can dry it and heat it just a bit I think you’ll see more vertical growth.

1 Like

I am with everyone else so far. I don’t see anything with the plants that concerns me. Your water pH is a little high for coco. It should be closer to 6 or below. I do 5.8.

DLI formula:
Avg PPFD X 3600 (seconds per hour) X light hours / (divided by) 1,000,000 = DLI
500 X 3600 X 18hrs / 1000000 = 32
600 avg PPFD produces DLI of 39
Both amounts are about where you want to be at that stage
DLI Screen-Shot-2018-12-28-at-11.19.14-AM

2 Likes

Thank you all for the quick responses!!!
I will lower PH to 5.8.
Do you think guys think I can raise the light intensity to 100% at 30" or at an even lower hight?

They look nice and healthy u may have a very little bit of nut burn starting i would back ur nutes off a bit

1 Like

When possible get as close as you can. If you have a dimmer, turn it down and lower lights. This will obviously save money on electricity but the light is more efficient and close to plant will get better canopy penetration. Just not so low that part or all of some plants end up outside it’s footprint.

Plants look fine so far.

1 Like

Thanks for the info I contacted the light manufacturer and they said put the light at 16" for veg at 75% and 100% for flower.
Does that sound right to you?
It’s a Mars TS3000 450w.

I’m thinking I’ll go down to 24" at 75% and monitor for a few day’s to see if the plants have a bad reaction.

Agree with above the look great, good job. I would say just make sure those big leaves don’t touch the soil, and if possible go to App Store look for the photone app, that can help with your DLI so you can get the max out of your light, and it helps take the guess work out. But great job so far keep it up, definitely on the right track

1 Like

Thanks for the info, should my DLI be as close to 60 but not over?

Do not quote me on this but I do believe I read somewhere that 60 DLI or more can cause fox tailing and you might run into some type of burn, or other problems cause your plant will try to do more chemically and you can run into root lock and other issues.I think

Is this a magnesium deficiency?

Is this a magnesium deficiency?


Yikes let me call in some pros, it might be magnesium and if so easy fix epsom salt, but like I said going to tags so pro to way in I would wait to steer u in wrong directions, these guys should definitely be able to help, and to those I have tagged thanks for the help
@Borderryan @oldmarine @beardless @PurpNGold74


Sorry bad pics click in magnifying glass and type in deficiency chart and you can get a better look

Thanks alot I tried looking at the chart but its hard to tell.