Help with Leaves Curling and Lack if Growth

Who can help me assess what’s happening here please.

Looks like it might be pH or over-feeding. Some information will help us help you with your plant.


A support ticket will help us help you. Can you please fill out a support ticket? Please include what type of water you are using (RO, distilled, tap.)

COPY/PASTE the below list into your forum post.

Answer these simple questions the best you can.

If you do not know, or do not use something; Just say so; Or post

NA (non-applicable)

• What strain, Seed bank, or bag seed

• Method: Soil w/salt, Organic soil, Hydroponics, Aquaponics, KNF

Soil brand and type

• Vessels: Pots, Grow beds, Buckets, Troths

• PH of Water, Solution, runoff (if Applicable)

• PPM/TDS or EC of nutrient solution if applicable

• Indoor or Outdoor

• Light system

• Temps; Day, Night

• Humidity; Day, Night

• Ventilation system; Yes, No, Size

• AC, Humidifier, De-humidifier,

• Co2; Yes, No

If growing Hydro some additional questions:

-DWC? RDWC? Autopots? Ebb and Flow? Other?
-Distance of liquid below net pot (DWC)
-Temperature of reservoir
-TDS of nutrient solution
-Amount of air to solution

Always try to upload a clear picture of any issues you may have to allow the community to assist you. Pictures taken under natural or white lighting are by far the best.

Add anything else you feel would help us give you a most informed answer should be included. Feel free to elaborate, but short and to the point questions and facts will help us help you in a more efficient manner.


What strain, Seed bank, or bag seed: I actually don’t know. Bought them from this site but didn’t keep the receipt. I have two different strains and both are acting the same way.

• Method: Hydroponics

  • Soil brand and type: rockwool - It had some algea on it, which is common, but just in case it was starving the plant, I swapped out the medium and have covered it with aluminum to prevent algea growth again.

• Vessels: Currently in a pod in a hydroponic system

.• PH of Water: I keep the pH as close to 6.0 as possible.

• PPM/TDS or EC of nutrient solution if applicable: using Jack’s Nutrients by Lettuce Grow. Part A is designed for general vegitative growing. Part B is for Calcium uptake. I’ve used it regularly for my vegetables with good success.

• Indoor or Outdoor: Indoor

• Light system: The light system with my hydroponic farmstand. They are LED’s with an added red spectrum and are about 6 " above the top of the plant.

• Temps; Day, Night: It’s indoors and the lowest we have the temp is 65. The normal is between 68 and 73.

• Humidity; Day, Night: Don’t know, but it’s relatively low.

• Ventilation system; Yes, No, Size: Nothing special, except that it is in a large open space and I assumed we don’t need any.

• AC, Humidifier, De-humidifier: Outdoor temps are about 40s-50s. Humidity typically between 35-60%. We don’t do anything special to alter indoor humidity.

• Co2; Yes, No: No

If growing Hydro some additional questions:

-DWC? RDWC? Autopots? Ebb and Flow? Other? Here’s a link to the system I have: It’s probably more like a drip system.

-Distance of liquid below net pot (DWC): Liquid is about 18" below the pot. Roots aren’t soaking in water. They’re not long enough. I moved them up to an upper row, just to be safe for the future.

-Temperature of reservoir: Don’t know, but assume it’s about room temperature of 68 to 70 degrees.

-TDS of nutrient solution: I don’t know how to figure the last two questions answeres.
-Amount of air to solution

Looked at that website and I couldn’t even find where to actually purchase items. Did you get actual Jack’s Part A&B? Do you have a pic of the nutrients you are using? With Jack’s A&B, you need epsom salt (magnesium sulfate) added in the mix.

Do you have brand and model? Many advertise a certain wattage and the actual draw is only 10%.

Seedlings and vegging cannabis plants prefer a more humid environment. Between 65-75%, and taper down throughout life cycle. Temps in high 70’s to low 80’s as well. Flowering cannabis is lower around 40% and temps closer to low 70’s.

TDS is Total Dissolved Solids. Basically the amount of what you put in, measured in Parts per million (PPM). This, with your pH is VERY important. Too high, you can go into lockout and your plants won’t receive anything. Too low, they will starve.

I hope some of this helps. Others should come along with possible solutions, I wish I had one for you. But the info is pretty on point.

Good luck and happy growing!!!

By the way, I do think it’s possible that I’m using too much nutrients. I’ve kept the water in the resevoir at a lower level so roots don’t soak in the water. But I haven’t adjusted the nutrients lower for the water being less. I will definitely adjust this immediately.

The reason I didn’t think it was the nutrients is because all of my other plants seem to be thriving.

Yes I use Jack’s A and B. This is what I use:

These are the lights being used. Meant to be used on my hydroponic system:

I’ve already learned the lighting isn’t good for the vegetative state. But I don’t even want to transplant these since they’re so stressed already.

You are using a waterfall system designed for lettuce or strawberries. You will not be happy with the results of this system growing cannabis. Lights are only part of the issue. You could repot into coco and top-feed Jack’s under decent lights and they should be fine.


Are you saying for the seedling stage, or instead of transplanting / completely getting it out of the hydroponic system?

I’d get them out of the system and under decent lights. Jack’s is fine: use the 3-2-1 program. But you gotta improve your lighting drastically. This is the most important single factor in growing successfully indoors. All processes are driven by light and without it disease, poor growth, poor yields etc are to be expected.