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Fungus Gnat? Heat stress? Help.. going downhill fast

S

smogo420

Member
Hello fellow growers.

Growing 2 Highland Thais' in soil indoors. Everything was going well - until we had a heatwave a couple of days ago and I noticed curling on the top leaves and drooping. Since then, I've had a bad case of taco leaves on upper growth that is deteriorating fast and getting worse.

I've lowered the temps to 20 degrees C at night, 25-28 C in the day with lights on. RH is around 65%.

I've also noticed 2 or 3 fungus gnats buried within the crevices of new growth - perhaps this is a combination of fungus knat damage and heat stress?

Looking for any suggestions from members on this great website - I need your wealth of experience guys! Thank you and peace

https://imgur.com/a/s6PB1M6
 
S

smogo420

Member
I must also add I've been using Rhizotonic recently at 2ml/L. Gave them a first feed of Oldtimers organic grow @ 2ml/L.

I'm starting to suspect a slight ph swing from the Rhizo causing Iron lockout?

Again, as usual with a lot of these issues, I suspect a combination of poor ph, pests, and heat stress causing this. Looks like they're not gonna make it
 
troutman

troutman

Seed Whore
The soil looks very dry and when it gets hot you can also raise the lights a little to compensate.
Increase feeding very slowly and they should turn more green. Try to find out what pH you have.
I like pH 6.2 - 6.6 in soil. Add a rusty nail or two to you water container for extra iron and leave it
there. Rust is iron. Epsom salt will cure your magnesium problem.
 
S

smogo420

Member
Hi troutman, thanks for the response - the soil looks dry but is constantly damp and moist... whenever I stick my finger in it's always moist, never dry.

It's only new growth that's affected - the lower leaves remain the same and healthy looking which leads me to believe it's a Fe or Mg deficiency.

The first symptoms I noticed was very aggressive curling at the petiole of the leaf - this then quickly spread to the rest of the leaf resulting in the "taco-ing"
 
troutman

troutman

Seed Whore
I only had bad taco experience once when the heat when too high. I closed my tent and
had forgot to turn on my fan. Now I make sure the fan is working before I close anything.
 
indagroove

indagroove

Active member
Veteran
What are you feeding them? How much, how often? What type of soil? What type of lighting? How close are the lights to the plant?
 
S

smogo420

Member
Did a first feed of 2ML/L of Oldtimers Organic Grow (NPK 5 3 3) 2 days ago as they appeared hungry. Using Biobizz Light mix for soil, watering everyday 2/3 days with ph 6.5 water.
Lights are QB LED's about 22 inches above the plant.
 
S

smogo420

Member
So just a summary of the symptoms I'm experiencing just to clear this thread up a little (apologies for the multiple consecutive posts, panicking a little here)

- Highland Thai (RSC)
- Biobizz Lightmix soil, soft water (ph 6.5)
- QB LED lights ~22 inches from plants
- Vigorous growth in the first 2 weeks. Plants looking really healthy. Slight yellowing on newer growth but otherwise healthy
- Noticed a couple of fungus gnats and green aphids feeding on the plant at around 17 days in. Removed said pests off the plant. Applied neem oil foliar treatment
- Started noticing curling at the petiole (base) of top half of the leaves. Growth slows down a little but still looking good.
- Big heatwave raised my room temps a bit (33 celcius) under the lights. Leaves started "taco-ing" and curling upwards
- Fed a dilute solution of Rhizotonic to reduce stress on plants
- Plants still growing fast at week 3 but considerably less vigorously
- Did a FIRST feed (3 weeks in) of Oldtimers Organic Grow
- Wilting and taco'ing getting worse. New growth is taco'd and twisted

This was the plants 10 days in, showing slight pale new growth and then at 14 days starting to "taco" https://imgur.com/a/fSO1dTu

This is them a couple of days later:
https://imgur.com/a/QtiX14e

I suspect I made a silly mistake by not ph'ing the Rhizotonic down and possibly caused the soil ph to be too high? My plant seems to be showing multiple lockouts - I suspect Iron and Mg in combination of heat stress and some pest damage?

I don't think I have much time left on these two...
-
 
indagroove

indagroove

Active member
Veteran
Honestly they don't look that bad to me. Just saying "QB lights" doesn't say a lot, because there are many types of QB's, but I'm thinkint you might wanna raise your lights a bit during veg if they are showing stress. I'm not too familiar with those nutes, do you know what the EC or ppm is at that dosage? I don't think a little ph swing is enough to make a huge difference. Prolly just heat stress and light stress. Raise the lights, and lower temps.
 
S

smogo420

Member
Hi Indagroove - thanks for the reply. I believe I am overreacting a little but this is based off of the speed of the deterioration.

Scoped the plant today and found what looked like a fungus gnat buried within the top leaf. There was also a thrip I found?

The thrip was fast and avoided me... I couldn't get him before he jumped off out of the pot! The fungus gnat was easy to remove, didn't resist... I'm hoping this isn't an adult root aphid? I've heard root aphids are quicker and harder to catch...
 
indagroove

indagroove

Active member
Veteran
smogo420 said:
Hi Indagroove - thanks for the reply. I believe I am overreacting a little but this is based off of the speed of the deterioration.

Scoped the plant today and found what looked like a fungus gnat buried within the top leaf. There was also a thrip I found?

The thrip was fast and avoided me... I couldn't get him before he jumped off out of the pot! The fungus gnat was easy to remove, didn't resist... I'm hoping this isn't an adult root aphid? I've heard root aphids are quicker and harder to catch...
Click to expand...

Fungus gnats don't usually cause huge issues but aphids and thrips can be a problem, so best to address those asap. I'd suggest a spinosad based spray like this: https://www.amazon.com/Monterey-LG6135-Garden-Spinosad-Concentrate/dp/B002BP12LI

smogo420 said:
EC of the nutes with the water is coming in at 0.6 EC.

Lights are 130W Samsung LED QB from Invisible Sun.
Click to expand...

EC seems too low to me. I would shoot closer to 1 EC at this stage. Also maybe raise the lights a bit until the plants recover.
 
T

TanzanianMagic

Well-known member
Veteran
smogo420 said:
Did a first feed of 2ML/L of Oldtimers Organic Grow (NPK 5 3 3) 2 days ago as they appeared hungry. Using Biobizz Light mix for soil, watering everyday 2/3 days with ph 6.5 water.
Lights are QB LED's about 22 inches above the plant.
Click to expand...
Light mix has almost no nutrients in them and needs magnesium lime to get the pH higher. So repotting into a richer soil is one solution.

I use light mix as a basis of a basic mix for supersoil - 1/3 of light mix, worm castings and perlite each. Plus magnesium lime, 2 tablespoons per gallon. The mix needs to rest for at least a month before use. Perlite needs to be put in a tub with warm water for at least 10 minutes, then scoop off everything that floats. Grow rocks needs to be put in a tub of water for at least a day, the longer the better, to absorb water.

Liquid feeding on a light mix only, only complicates things, because you're now in charge of nutrients, pH, EC, etc.
 
S

smogo420

Member
TanzanianMagic said:
Light mix has almost no nutrients in them and needs magnesium lime to get the pH higher. So repotting into a richer soil is one solution.

I use light mix as a basis of a basic mix for supersoil - 1/3 of light mix, worm castings and perlite each. Plus magnesium lime, 2 tablespoons per gallon. The mix needs to rest for at least a month before use. Perlite needs to be put in a tub with warm water for at least 10 minutes, then scoop off everything that floats. Grow rocks needs to be put in a tub of water for at least a day, the longer the better, to absorb water.

Liquid feeding on a light mix only, only complicates things, because you're now in charge of nutrients, pH, EC, etc.
Click to expand...

This would explain everything, thank you for this! I wish I had known this 3 days ago when I repotted them into... you guessed it, a bigger pot with more light mix :wallbash:

Perhaps I could make my own soil and repot before I flip the lights? I won't want to be vegging this landrace sativa for much longer...
 
R

RED 1

Active member
Seedlings are suffering because of high temps
Very easy fix,25C daytime, just under 20C night time
BioBizz Light is good, you are under watering,no need for a nutrient fix
Plain water,lower temps they'll start looking much happier pretty fast
 
S

smogo420

Member
Hello everyone,

Thank you all for your responses!

After agonisingly pondering over what could be wrong... I eventually diagnosed this as an iron (Fe-) deficiency based off the new growth being yellow (new growth at the internodes being the most obvious) and the lower leaves being unaffected.
I suspect the Rhizotonic may have spiked/increased my pH, locking out iron.

A simple flush with 6 pH'd water, 3 hours later - the yellowing on new growth has almost miraculously completely recovered and growth is noticeably more vigorous and healthy looking.

Will post pics later today. Thank you everyone for your help and response. Seems I was a little too high yesterday too and panicked a 10-fold more lol
 
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