Yellow Leaf Perimeter

[jumbo_grimes]

Details of Grow
Room: Closed Grow Environment (CGE)
ambient Temp: 24 C Day 19 C Night (+/- 1C)
RH: 50% Day 60% Night

Technique: NFT Substrate: Oasis Foam

Nutrient : Budzilla
EC: 2.0 (20CF)
PH: 5.8
Nutrient Temp 21 C (+/- 1C) Aeration 550 lph
Test Calibration Weekly
Nutrient Change Weekly
Lights: 600watt Lucagrow HPS 150 Watts per square foot
Above Canopy 300mm
Canopy Temp 28 C
Co2 1800ppm

Hi,
I recently fought of an attack of fungus gnats which led to pythium, which led to dead roots, which led to very low ph (4.4), which as you can guess led to total nutrient lockout. Now I have gotten everything back on track I am still finding this defect on newly growing leaves. Any ideas?

Treatments used were:
Fungus gnats: Pyrethrum (adults) BTi (Larvae)
Pythium: Pythoff & Trichoderma

Can't seem to insert image to post because I am new, but picture is in my gallery at /gallery/data/500/29333yellotip2.jpg

 

[SweetIndica2]

Are you sure those are what the problems were? Or just guessing? Post some pics and i should be able to help you. Everything seems normal from the numbers you posted, only thing i notice is that your temps are a little cold at night (not too bad though).

To get rid of the fungus gnats, mix hydrogen peroxide (3% with no scents/etc added) at a 4 to 1 ratio with water. Water your plants with this, and it should kill the larvae. I'd also spray the plants with neem and get some no pest strips in there if you can.

Try and get your PH stable as best as you can. Are you sure it's dead roots that are causing the PH problems?

Pictures will help me identify your problem(s) though. Good Luck

 

[jumbo_grimes]

Fairly sure it was the dead roots causing low PH as the problem didn't fix itself until I removed all the dead matter from the gulleys. The picture is in my gallery, I couldn't embed it in my post, I guess because I'm a new member.

 

[jumbo_grimes]

bump

bump

bumped

 

[SweetIndica2]

Looks like a magnesium deficiency to me. Try giving them some epsom salt or cal-mag. If using epsom, you should give them about 1/4 tsp per gallon of water, if using cal-mag i would give them about 3-5ml per gallon of water.

EDIT: Could also be a zinc deficiency, although they are more uncommon than an mg deficiency. If your feeding them a nutrient with potassium, then it's probably not a zinc deficiency.

 

[jumbo_grimes]

Yellow leaf Perimeter with photos

Yellow leaf Perimeter with photos

Thanks for your response, still getting over it