weird looking marks/burns on leafs

[monkee]

Hey folks. Details of my grow are:-

 

Indoor/Outdoor: Indoor

Growing Medium: 7litre pots of Humax potting compost with 1" layer of washed sand on top to prevent fungus gnats

Growing Style: natural but with a small amount of LST if plants need bushed out a bit

Watering/Feeding Frequency: 1 - 2 litres(stop watering when see water running out of base) every 3 - 4 days depending on how thirsty plant looks (fan leafs start to droop slighly when needing watered)

Nutrient Strength (PPM/EC): 5ml scoop of phostrogen plant food (NPK 14 : 10 :27 plus trace elements) every second watering.

PH Levels: Not sure - but cant be too bad as have done 5 grows using exactly same setup and methods.

Temperature/Humidity Levels: 30C (86F) max and 15C (59F) min

Air Flow/Fans etc.: 100mm 12 v computer fan pushing air into cool tube and 4" RVK pulling air from cooltube thru filter and along 10m of flexi duct with a 12" wall mount fan moving air about room

Lighting Type (CFL/HPS/MH etc.): Metal Halide

Total Wattage: 400w

Growth Stage: Vegging

Plants Age: 12 weeks approx

Cannabis Strain: Citral - apparently - thats what it said on the packet at least!?!?

 

 

I have done about 4 or 5 grows with this setup and have never seem this kinda thing before. The grows have all been done from clones that were seed grown on my first grow - so im now onto my 3rd or 4th generation of clones. I have 3 different plants (they were from 3 different mothers as out of 5 seeds only 3 were female) affected with this problem. The leafs are showing kinda horizontal lines on them - at first it appears as sort of matt areas that can be seem because the rest of the leaf has a healthy shine to it. It then seems to dry out and either turn brown or stay green but either way the areas affected on the leaf go crispy. Also on some of the smaller leafs there are brown spots apppearing and some others are turning dark along the edges and shriveling. I soaked them all in the bath 10 days ago and then this started to happen about 5 days later. Is this just the result of over watering or is it a combination of problems? Any ideas? I have already lost 1 of my plants to this problem - she went from nice and healthy looking to all the leafs - even growth tips - having burnt or shrivelled parts on them within 4 days of her bath and looked prety fu©ked by the 7th day! Sorry the pics are not to hot - camera dont like having dark lens put in front of it!! Any help or advice would be greatly recieved - apart from telling me not to put them in the bath again - you can shove that now that i seem to have learned it the hard way !! Thanks - Monkee

Couldnt get pics to upload so have linked to them from a hosting site.

 

http://i302.photobucket.com/albums/nn93/JG53_Monkee/tonys%20boat/IMG_0712.jpg

http://i302.photobucket.com/albums/nn93/JG53_Monkee/tonys%20boat/IMG_0704.jpg

http://i302.photobucket.com/albums/nn93/JG53_Monkee/tonys%20boat/IMG_0708.jpg

http://i302.photobucket.com/albums/nn93/JG53_Monkee/tonys%20boat/IMG_0706.jpg

http://i302.photobucket.com/albums/nn93/JG53_Monkee/tonys%20boat/IMG_0710.jpg

http://i302.photobucket.com/albums/nn93/JG53_Monkee/tonys%20boat/IMG_0702.jpg

Edited May 7, 2012 by monkee

[Devilspine]

Hey monkee, my guess from those shots would be a magnesium definciency which can be caused by root enviroment being too wet or acidic.Quickest way to sort a mag deficiency is to foliar feed with a cal-mag or epsom salts...hope this helps..devil..

[Ra Indus]

Rock dust is a good 'organic' way to treat magnesium deficiency. I've never seen magnesium deficiency that has caused those strange, linear patterns though.

[Frazz]

yea sorry to hear that youve already lost one .. thats bad .. regardless of you using this method for 5 successful grows, i urge you to invest in a PH meter, also a PPm/EC meter, not only for the nutrients going in but also what is coming out the drain holes these two meters would be a worthwhile investment, .. otherwise you are working in the dark

 

next I would flush out the pots thoroughly with plain water , heaps of water .. ... then resume with half-strenght nutes every 2nd watering, alternate nutes with plain water

dont stop watering when it starts to run out the bottom as eventually this will result in a toxic build-up of nutrient salts in the soil .. e.g. when you feed/water plants make sure 25% of the volume you are watering runs out the bottom .. like if you give 4 litres you want 1 litre run out the bottom ..

 

this is just what i would be doing as i believe the problem you are experiencing is a result of nutrient salt buildup within the soil

 

[Buddybudboy]

I had similar problem years back, I'm with frazz on this. Reduce your nutes the leaves get a chemical burn from high nutes.

 

Good luck hope you get it sorted.

[monkee]

ok - so the story so far....... got some epsom salts - mixed it in my sprayer as per instructions and sprayed 10 mins before lights out last night. Today the plants are worse looking plus they have a kinda crystalised residue on most of the leaves from the foliar spray. its on the topsides of the leaves but i presume it must be overspray as i sprayed the underside of the leaves. Is it normal to get this from spraying epsom salt and shoud i spray them with water to wash it off or just leave it. The soil is now pretty dry so tonight i decided to mix it up in my can and try feeding it thru the roots. Will keep you all posted but from the way one of them looks...... well put it this way - if i lived on a farm and it was my pet dog id be taking i round the back of the barn and giving ti both barrels from the shotgun to put it out its misery!!

 

@ Frazz - they were all flushed about 2 weeks ago now and its since then this has started. I thought it was perhaps some extreme reaction to over waterin from their flush (i use 6L pots and used 25L of water for each one). Since flushing they had been watered once with only a 1/2 strenght nutes. Do you still think it worth trying another flush? As for ph meter - i bought one off a well known auction site. It was cheaper than a packet of tobacco!!! Fu©kin thing didnt even last as long as a packet of tobacco tho hehe. il see how much i can get a decent one for this time and i think there might be an old ppm meter at work i could snaffle.

 

cheers - Monkee

[Frazz]

hey monkee .. yea mate this is no good aye ... the PH meter even if ya cant snaffle it take some mixed nutes in and test them .. im not crazy about this Phostogen NPK 14 : 10 :27, thats heavy duty but has it got any Trace elements? one dude i spoke to said he used phostrogen for weed but he had to add dolomite lime , well bugger that better off to use a nutrient specifically for weed imo ... honestly the soil should have enuf in it to support life without extra nutes for another week or more so maybe put the phostrogen aside for a while

 

humax potting mix, so youre in uk? thought ya had an accent ... i checked that out and it does have NPK added to it already so definately stop the phostrogen

 

flushing would not hurt them ive done mega flushing heaps with no adverse results, but its best to flush with PH adjusted water .. thats maybe where a problem lies in the PH of your water to begin with? yep the el cheepo PH meters are ratshit but there is a little ph tester from Flairform its not a meter just little bottle of liquid ya mix with some water and compare it against a clour chart , they work too i used one for years!

 

apart from these im stumped

 

dunno if ya can get that ph gear in uk?

[monkee]

yeah im from sunny old scotland - the reason i use humax is cos the bit that makes it is about 20mins up the road from me..... Gotta support the local economy in this harsh financial climate!!! I can get them ph drops here but wasnt sure how ggod they were but i think il invest in one as they are quite reasonably priced. As for EC meter - i forgot to look for it at work today but will try an remember the morn. From testing with my cheapo meter tho my tap water was a fairly constant 6 to 6.8 but that was about 2 years ago so it could well have changed drastically since then!! As for the phostrogen yeah it has trace elements in it but im gonna pack it in as today i found a bottle of canna veg that i forgot i had - and its still in date WOOOHOOOWW!

 

Anyways - how do you make sure ur plants dont suffer from overwatering after flushing them. I was thinking about it this morning and i wonder if my problem is a combination of 2 things? Perhaps over fertilisation AND over watering or something??

 

Cheers - monkee

[Frazz]

with the watering its sort of trial & error by the weight of the pot , you know, before watering lift pot to feel the weight, then after a watering its going to be heavy work off that, you can let them go until point where the leaves wilt before watering, then the weight of pot gives you a baseline to work off ... the hotter the environment around the plant the greater rate of transpiration of water from the plant

 

another thing i was thinking, that sand (is it clean sand? like not salty or something) on the top, does that wash down into the soil, cause if it does then that would greatly reduce air within the soil structure by filling the gaps in soil with fine sand (roots need fresh air exchange too) and keep the soil wetter than otherwise .. just some ideas for ya

 

[hidden.monkeys]

Good luck saving that plant Monkee, it looks like it needs some mothering. Haven't experienced anything like that before, those marks are pretty foreign to me.