Edges of leaves curling upward and drying out


#1

Humidity has been on the lower side of 40% and as low as 25% it very rarely seen the 40% mark. do not know the strain. Seeds came from bag seed. The last time I checked PH level it was 6.3. Temp has been around 74 degrees. Last watered about 5-7 day’s ago. Moisture meter still say’s wet when inserted into soil deeper than about 4-5 inches. Lights are about 36" above plants. I have two fans on them. I know there not getting to hot from the lights. This started after I watered them the last time. I did use some Miracle Grow, Plants are growing great getting bigger everyday but the edges of the leaves are very dry and curling up any suggestions.


#2

I’am using a 600 watt air cooled hps Light. The medium is a mix of potting soil, organic compost,cow manure & compost, peat moss, and Perilite.


#3

You were doing great, and then you burnt them with the Miracle grow. You have to be careful suing manure, and compst. You have to amke sure the nutrients are almost completely depleted from the compost before adding more nutrients; Especially chemical nutrients such as Miracle grow. Just water with PH’d water at 6.5 and monitor new growth. You should come out OK. :slight_smile:


#4

bud420: cannabis is the toughest mother on the block, I mean it takes a lot and gets back to tickin…
we all want to be proactive when it comes to our girls, but with cannabis being smarter then mere humans it is better to let the lady lead.
your soil mix has goodies in it and when they get low the plant will show you.


#9

I think I am having a similar issue. Just set up an 18pot Alien Hydro system in a tent. all was going well until about 3 days ago when i noticed what appears to be slight nute burn on the tips of some the slightly more developed plants whose roots have already penetrated the water.
I have 2 electronic PH testers (calibrated religiously every 2 or 3 days) Today, one meter shows 5.9 and the other 5.3… I average the 2 and get 5.6. However I was only using the meter that gave me a 5.9 today until 3 days ago when i decided to check the other meter. Normally, the meter I use gives me readings of 5.5 - 5.8 but usually sits at 5.6 (its a 300litre system so the PH tends not to change and its only very early in the grow). Upon trying the more expensive meter it gave a reading 2 days ago of 5.0 so i added PH UP… thats when i noticed the burn… and now the tips are starting to curl up…

i calibrated again this morning and same deal. 5.9 on one meter and 5.3 on the other… i made no changes this time.

could this issue be a combination of PH and nute burn?

The PPM is at 470… slightly less than FOX feeding schedule states…

The plants in the pic germinated from seed on the 20th April.

Can someone confirm this issue and the relevant treatment… I dont really want to change the water…

I experimented with one plant just by rinsing the rockwool it is rooted in with PH adjusted water and it seems a bit better than the others… maybe this will suffice?? thanks folks.


#10

Plants are too young for Nutrients. That is the entire issue. You are burning them up. :frowning:


#11

Had same problem have them good flush won’t water again for bout a week


#12

Thanks for the reply guys…very much appreciated.

I drained some water from the system, and rinsed the roots with fresh ph corrected RO water and let them go for another 10 or so days.

Its now 2 weeks later and the difference in the size of these plants has surprised me given the initial set back… It doesn’t seem to have hindered the root development.
I was becoming concerned again though after noticing what looked like fert burn again.

So 2 days ago, I drained just over a 1/4 of the water from the system (60L) and replaced it with purified ph adjusted water (5.6)… and I added another 5 L water today. It has effectively reduced the EC to 270us and the TDS is back to 160.

Could this now be heat stress related. Im having difficulty getting even temps throughout the grow and not all plants are curling their leaves or burning for that matter… Its looking a bit like a deficiency.

I cant see how they are burning with such low EC levels. They couldn’t want for more light and I’m enriching the aeration system with an oxygen generator (no CO2 as yet) so they should have consumed more food… please correct me if Im wrong…


#13

I think it probably is heat related. What are the temps? Reservoir and canopy?


#14

Yeah, I reckon some of it is heat related, at least the curling up and in of the leaves.

Water is chilled and ranges from 19C (dark hours) to 23C (light hours). Canopy ranges from 21C (dark) to 32C (light).
I am trying to get the temp down to 25C during the light hours, and 18C at dark, but its proving very difficult.

I’m swinging away from fert burn now because the levels are low and the plants are powering along…

I’m tempted to swing towards the heat and perhaps a nute deficiency (manganese lockout since ph rarely gets down to 5.5 (usually 5.7), or am I clutching at straws?


#15

I might be tempted to say that type of curl and twisting also looks a little like overly acidic pH, but you seem to be checking it and keeping it in a good range. A bad pH would make sense as far as the spots and contributing to a deficiency or toxicity and result in similar looking spots on the leaves.

Something to think about, continuous correcting without a complete reservoir change can lead to an abundance of the nutrients that make up the pH adjuster and then also lead to toxicities or “nute” burn.


#16

Ahhh, yes, you make a very solid point and one I had not considered. Due to the high volume of water in the system (300L), I rarely, if ever need to correct ph after the initial adjustment as its very stable. I’ve not once in 4 weeks, had to adjust the ph of the water in the system… However, now that I have replaced 1/4 of the water, perhaps there is now too much ph down ( i think phosphorous?). Due to the already low Nute levels, I have opted to attempt a 1/2 strength foliar application. If this doesn’t show signs of improvement, I will have to suck it up and dump the entire system and start fresh. BTW, I am using FoxFarm Nutrients and up until I dumped some water, the system strength was about half of what they recommend. The root systems couldn’t be whiter or more abundant so I dont think ph is overly acidic since too much acid should damage the roots… I think you nailed it with the ph nute scenario… perhaps a burn from too much ph nute… I will let the ph slide back up closer to 6.0 and see what happens to the curling leaves.
Thanks for the heads up…


#17

Its now 30 days since I dropped the seeds in water and cranked the system up for the first time.

I think the growth is acceptable given the time period however there is still an underlying issue.

Yesterday, I completed a full system change, brought the EC up to 380us with a PPM of 270. I’ve adjusted the PH to align more with FoxFarm recommendations on their feeding schedule…I was running between 5.5-5.8, but now I have it at 6.0 to see what happens. Fox say to maintain between 5.8 & 6.3 so I’ve met them half way. Fingers crossed the problem resolves itself… They do appear happier today though I did trim some of the damaged fan leaves. These should be ready to start taking cuttings in a couple of days before flowering???


#18

I am on my first grow. I’m following the grow bible. Are they supposed to have the purple color like this? Using growers pot with 50/50 mix miracle grow potting mix and miracle grow perlite. T5 6500k fluorescent 24/7, grown in closet with heavy mist 2/day and 12oz tap water once a day. Idle what strain they are. These are from some decent Mexican dirt weed I had awhile back. Planted seeds Feb 4 transplant Mar 8 started in germination soil. Heavy vegetation started about Mar 16. How am I doing? Can I get big buds with unknown strain ? I think I have a male and female by the difference in size gains, is this feasible ?


#19

They really look good but you can’t tell if it’s male or female until you actually sex the plants , not by they growth . But you definitely can get big buds with any plant , real strong light and good nutrients and no stress to the plant is how you get fat ass colas the size of one liter bottles like my last grow .