This is my first time trying to grow, and up until about 2-3 weeks ago things were going well (as far as I could tell). It’s a gorilla glue in FF happy frog soil, and I stupidly planted it in a 5gal cloth pot before doing enough reading to realize I should’ve started in something smaller and transplanted it as it got bigger. I’ve been watering roughly every 2-4 days, very carefully early on with how much because I didn’t want to have the soil damp for extended times and that seemed to be working fine for a time.
About 3 weeks ago I noticed the lower leaves on the plant were starting to yellow on the tips of the leaves, it progressed up to the next set of leaves slowly, over about another week or so. I had done a single watering with some fertilizer around that time so I thought maybe it was nutrient burn if the soil was already plenty. I switched back to only giving it ph balanced water (7.5) and the yellowing didn’t progress any further up, the first set of leaves continued and have pretty much shriveled away at this point but the second set that just had yellowing at the tips hasn’t really progressed.
The leaves at the top of it appeared to be curling inwards, and as far as I could research and determine it may be light/heat stress. So I raised the light up a few feet and dimmed it just to be safe - it’s now 3-4 feet above. The temps usually sit around 71-75f on average day to day and RH about 50%. Unfortunately the curling continues and I’m at a loss of what to do or what’s going on.
Is this obvious to anyone more experienced what I need to do to correct and get this back on track?
You may need to dial in your environment (VPD), your light (DLI), and your feeding/watering technique.
If you look up vpdchart dot com. Your humidity vs air temp vs leaf temp.
If you can get a laser temp gun set emissivity to 0.98 to get an accurate reading. If not temp gun… Many guess or assume a degree or 2 or 3, etc… Less than the air temp.
Depending on the stage and week of that stage your plant is in there’s optimal settings for temp and humidity.
I am currently a few weeks in veg. At 83f and 68%rh. Leaf temps about 80-81f. To find the correct range of vpd check the chart.
Again set your daily light integral according to your plants stage… Checking chart… Raise the light like you did… Each manufacturer of lights usually has recommended height above canopy listed. Them recheck your DLI to ensure they are getting enough light… Be it… 12, 18, 24,or? Hours per day of light. You will need a par meter or quantum meter to check your ppfd.
The best dli chart is on the link to the thread by @Nicky
Also you want your water/feeding pH at about 6.5 for soil. Water to runoff then let dry… The plant will tell you when it needs water… Also get used to lifting the plant… Dry is much lighter than watered.
Welcome friend, what light do you have?
And how long have they been growing in the pot?
Those temperatures and humidity are good. I’m curious do they have good fresh air circulation ?
The canoeing up is typically a sign of heat stress at the canopy and that is the response. Kinda like us sweating to cool off. Cannabis will curl up like that when too hot.
Hey thanks! I haven’t checked runoff, just bought a TDS meter to check but waiting for it to arrive. Using Advanced Nutrients fertilizers. I will have a look at the app to figure out my lighting stuff as well, appreciate it.
Hey thank you, I’m got a Viparspectra P600 LED light for this (set to 50% currently). Seedling sprouted 43 days ago (planted 47 days ago). I have a AC Infinity Cloudline S4 in the tent to circulate the air (tent is in my home office), I may get an air quality tester or something though.
Leaves curl like that when they transpire water too quickly. Like a piece of wood that curls in the sun because one side is drier than the other. So a combination of heat from lights (too much or too close) wind from a fan, low humidity will do it. The water leaves the topside faster than the bottom and it curls or tacos the leaf.
Interesting - I have a fan on separately from the AC Infinity to help move more air around in the tent. Would you suggest I turn it off or only have it on for limited amounts of time? I have as much as I can get automated in the tent (humidity/temp etc) and am working to fix the humidity to get it a bit higher but would it be beneficial to change the fan to a schedule of some kind? Something like on 2 hours, off 2 hours (or whatever else) or just keep it off?
Try to aim it so it moves the air more gently.
If nothing else away from the area you see the curling.
I keep mine higher than the canopy so it gently moves the leaves.
My house doesn’t have any ducting so certainly a possibility but the ac infinity I expected should be cycling the air out (with a charcoal filter for the smell). Some of the curling leaves are now graying on the edges, but the upper most are looking okay I think. Will see if any improvement over the next week and test my runoff once I get my TDS meter.
