Curling Edges in 2,5 weeks old plant

Last month, I dumped 4 plants due to what I think were russet mites. I started treating them with wettable sulfur, and after 2 weeks, I decided to start over.

I cleaned up the grow tent with alcohol, cleaned the pots, submerged them in a chlorine solution, and made a new substrate. The temperature changes between 29 - 30 ºC during the day with lights on (240W quantum board – using ~250 ppfd in this stage) and 25 - 27ºC during the night with lights off. I'm in Brazil, and the summer has just ended. The humidity in the grow tent oscillates between 58 - 70%. Im watering every 2 days.

Now I have 5 plants, and they are only 1.5 to 2.5 weeks old, but I started noticing some curling edges. I sprayed them with Spinosad (270 mg pill diluted in 2.7 liters of water) 2 days ago.

I also noticed some tiny fast white bugs in all substrates (none of them on plants).

If something goes wrong, I'll only be able to start again in August. So, I ask you guys, since it's my third time planting, if I'm overreacting or something is actually wrong, and if so, what could I do to resolve it.

I also have, besides the Spinosad solution and wettable sulfur, neem oil.

thats just leaf matter catching up with its growing, nothing to worry about. keep an eye on her, just in case, but your good

don't know about the bugs

I know "buy more things" isn't always the answer, but predator mites (mites who kill mites) and other predatory bugs are a decent measure I've seen work.

go go kid said:

don't know about the bugs

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I can almost guarantee thats a predator mite. I have them in all my soil. They eat bad bugs. You can also tell by how fast they move. Most bad mites move slow. Predator mites, move fast.

Little on the warm side but other then heat you could have you lights to close for curling. Curing up is usually an avoidance move by plant trying to minimilaize surface area of photo bombardment or conserving moisture do to vpd outta whack and transpiration. Back you lights off should be minimal 24 inches away at this stage with a 240 hlg

Thank you all for the replies, I learned important things.

Updates (5 weeks from seed)

I adjusted the VPD and the problem resolved itself, or so I thought. Now im about to turn 12/12 and the same problem appear.

But here’s new info:

4 of them are in an aerated substrate with 0.7 EC plus 20% worm humus. I placed the fifth plant in a ready-made flower shop substrate (I don't know what EC it is) and its very compacted.

After 3~4 weeks I started fertilizing all 5 plants with Biobizz, I started slowly until I got the correct dose. Now none show any signs of deficiency (at least not the ones most known from internet search). I am also using neem oil as a precaution and there is no visible sign of any kind of bugs.

Now the VPD is a little low, I haven't increased the light and it's far from the plants (40~50 cm with 50% power both 120W LED). So I suppose they're not curling because of that and I discard any bugs because one plant does not present any problems.

The most likely problem is with the substrate (the same mixture as the time I threw the plants away last month, thinking russet mites - i checked the roots and all seemed health to my eyes). I'm thinking about some micronutrient deficiency.

Does anyone have any idea what it is and how I can get it right?

Curiosity: Does anyone know which (micro)nutrients caused the difference in color between the plants?

This one is the ready-made flower shop substrate:


The others (same genetics):


The others (different):


All of them:


Again, thank you all

Petinha88 said:

Thank you all for the replies, I learned important things.

Updates (5 weeks from seed)

I adjusted the VPD and the problem resolved itself, or so I thought. Now im about to turn 12/12 and the same problem appear.

But here’s new info:

4 of them are in an aerated substrate with 0.7 EC plus 20% worm humus. I placed the fifth plant in a ready-made flower shop substrate (I don't know what EC it is) and its very compacted.

After 3~4 weeks I started fertilizing all 5 plants with Biobizz, I started slowly until I got the correct dose. Now none show any signs of deficiency (at least not the ones most known from internet search). I am also using neem oil as a precaution and there is no visible sign of insects.

Now the VPD is a little low, I haven't increased the light and it's far from the plants (40~50 cm with 50% power both 120W LED). So I suppose they're not curling because of that and I discard any bugs because one plant does not present any problems.

The most likely problem is with the substrate (the same mixture as the time I threw the plants away last month, thinking russet mites - i checked the roots and all seemed health to my eyes). I'm thinking about some micronutrient deficiency.

Does anyone have any idea what it is and how I can get it right?

Curiosity: Does anyone know which (micro)nutrients caused the difference in color between the plants?

This one is the ready-made flower shop substrate:
View attachment 5390457

The others (same genetics):
View attachment 5390460 View attachment 5390461

The others (different):
View attachment 5390459 View attachment 5390458

All of them:
View attachment 5390462

Again, thank you all

Click to expand...

Are you spraying it with lights on?

FatherNelson said:

Are you spraying it with lights on?

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No, always 10~5 min before turn off.