Classic heat stress / or is it? ( no picts:()

[Canada]

My plants are showing signs of heat stress the serrated edge of the leafs are pointing up and sound leafs are starting to curl up .. i did hit them with magic cal last week and the bed of plants had been treated with epson salts so i don't think its a mag problem ..I cuirrious if low humidity can cause this stress as my room temps never got over 75 degrees . i have been running a heater at nights cause it had been cold and even then my room only got to 70 degrees .
Im wounding if the heater is drying the room lowering humidity

Any ideas?..........

 

[RubeGoldberg]

did you treat it with the epsom salts and magic cal to fix yellowing earlier on?

 

[Canada]

epson salt was added a few weeks ago and then i used half strength magic cal 5 days ago casue of red stems and yellowing both of which look great now but i have what looks like heat stress now .. I think my room is too dry going to hang up some wet towels and i jsut mist them right befor lights out . Only 1 strain is being effected by this and all the strains are in the same 4x8 bed .

 

[RubeGoldberg]

what base nutrient are you feeding?

It sounds like you have a pH related lockout and adding the calmg may have caused the issue to get a bit worse

 

[Canada]

AN jungle juice ..... I have already started to flush the bed with plain water .. Also im at day 10 of flowering

 

[teemu shalanie]

maybe toooo high ppm ? for day 10 what is your ppms, whats medium ?
TS

 

[Canada]

mostly peat and 20% perlite

 

[RubeGoldberg]

whats the runoff pH? you're probably gonna be coming out somewhere lower than 6.0 and need to flush it.

your peat/perlite medium, is it an off-the-shelf medium like pro-mix? or did you mix it yourself? if so, did you add dolomite?

 

[Canada]

i mixed it myself like 2 weeks ago . ill take a picture here tonight and load it up

 

[RubeGoldberg]

i mixed it myself like 2 weeks ago . ill take a picture here tonight and load it up

was there dolomite in the mix though?

peat on its own with perlite is relatively acidic, promix and sunshine usually have liberal amounts of dolomite mixed in outta the bag.

measuring the pH of the runoff will be key to fixing your issue most likely.

 

[Canada]

my ph pen is done i need to pick up a new on so the ph is an unknown and i have no humidity gauge aswell ... the problem only seems to be right at the serrated leaf tips its really minor i knew right away the signs for heat stress but my room has never hit over 73 degrees and this porblem only statred to happen after i added the space heater to the room for over nights when the lights where out ... So im really leaning towards low humidity jsut cant seems to find any pictures online to reference .... will low humidity cause leaves to look similar to heat stress?

 

[Canada]

No lime was added . Doesnt lime take months to become available to the plants ..

 

[RubeGoldberg]

No lime was added . Doesnt lime take months to become available to the plants ..

nope, it can start being available pretty quickly, its not so much for plant uptake as it is to buffer the medium and keep the pH in a reasonable range
, its pretty much mandatory for growing in peat.

since peat on its own has a pH of mid 4's usually and the perlite is inert

The chart below illustrates the problem. You'll see that nothing is really available to the plant at the lower pH of the peat.

Your best bet will be to hit up home depot, get yourself some dolomite (nothing too powdery, but nothing too course) and sprinkle a tablespoon or two on the surface of your peat. Then flush some water through.

Buying a pH meter will definitely pay itself off as well though.

 

[Canada]

Ok ill add some lime tomorrow in a few days will the damage reverse itself ok shpuld i just be looking at the new growth for improvments?

 

[RubeGoldberg]

getting an idea of what the pH is doing on that run-off will help greatly as far as the game-plan for fixing it.

Foliar spraying the magi-cal will not be a bad idea while you're waiting for pH to dail back in on the roots.

 

[Prairie Boy]

Canada,if ur doing any foliar spraying I would suggest spraying a half hour Before lights ON.I would also suggest getting ur lights on temps up a bit and once you get ur ph in check they should jump.

Cheers PB

 

[Canada]

getting an idea of what the pH is doing on that run-off will help greatly as far as the game-plan for fixing it.

Foliar spraying the magi-cal will not be a bad idea while you're waiting for pH to dail back in on the roots.

what rate should i mix it ?

 

[W89]

I would listen to RB he seems to knw his shit.. peat alone is very acidic the usual rate is 1 cup per cubic foot of soil with organic growing..But thatswith say1/3peat/1/3compost/castings and 1/3 aeration.. but just running straight peat I'm not 100%

 

[RubeGoldberg]

what rate should i mix it ?

I'd say you're probably safe spraying it at whatever the bottle mixture rate it.

as prairie said, when the lights are off.

the mg should get shit moving around in the plant while you solve the pH uptake issue in the roots.

 

[Canada]

I took your advice Rube about spraying the plants down and i flushed with a large amount of water . i also hung up a wet towel right in front of my fan and the problem seems to have corrected itself thanks for all the support form all of you