Is this a nutrient issue or a watering issue possibly?

A question of a fellow grower:
Trying to grow Critical Purple autoflowering in an indoor grow tent. In the 4th week now, have been experiencing leaf discoloration and curling since about two weeks ago. Just started using Nuke Heads 20-20-20 nutrients once per peek, diluted to about half the recommended dosage, so about 1/2 tsp per gallon of well water. My soil is Miracle Gro moisture control with NPK ratios of .21/.11/.16. I have a 600W MH bulb but am only using 400W as the temperature gets too hot with a 600W bulb. The average temp has been 80 degrees F with average humidity of 40 percent. I am very concerned about the curling and discoloration of the leaves. Is this a nutrient issue or a watering issue possibly?

In the picture the new growth on the top looks to be clawing down. I would back off on the nuts. Water with pH water for a couple of weeks watch your new growth and see what it tells you. Hope that helps good luck

It’s the Miracle Grow soil that’s burning the plant.

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My well water has a pH of 7.3. When you say to use pH water, what exactly do you mean?

Ph water means to get the water to a proper Ph for cannabis plants. In soil that means a Ph between 6.3 and 6.8.

However, your problem is too many nutes in the soil. Miracle Grow is not recommended because it has slow release nutrients in it, so every time you water you’re allowing more nutes to enter the soil, thereby burning the plants. I think you should transplant into some more appropriate soil.


I agree with raustin to get back on path would be good to get some organic potting soil with no additives. Repot go easy on the nuts till your new growth starts looking healthy. Use your pH meter. To check your pH after you put the nutes in the water.

NOT a good idea to use prefertilized soil. Then adding 20/20/20 is pretty much a death dosage.

The 20/20/20 stuff has fried the little lady. Bloom Boosters should NOT be used during veg.

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Would Fox Farm’s 6.3-6.8 pH soil be a good choice?

Thank you all for your help! I’ll do everything I can to save them.

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Yes, foxfarm soils are made for cannabis, so that would be a good choice.

Great, thank you so much!

Another satisfied customer. :wink::wink: good luck with ur grow and welcome to the forum

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I transplanted to fox farm. The leaves are burnt. Should the burnt leaves be trimmed off?

No, just leave them alone. If they start to die then take the leaves off.

Ok, Just the leaves or stems and leaves? they are turning brown and are crispy like.

Can I see a pic?

sure, give me a minute

You didn’t feed her, did you?

Not sure what you mean by feed her? do you mean give nutrients? if so, then no I didn’t feed.

Ok, I think she needs to recover from the Miracle Grow. DON’T cut off any leaves, I know it’s tempting, but don’t. She needs those leaves for photosynthesis even if they’re damaged.

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