hi,i have a plant that's around a foot tall and is showing signs of being female,trouble is there's a lot of yellowing to the top few sets of leaves,between the veins,i've flushed the pot with epsom salts a couple of times and tested the ph of the soil which is showing as 7,it's growing under a 400watt dual spectrum hps lamp,which is about 2 and a half feet above the plant,i'll enclose a couple of pictures to see if anyone can figure out what's wrong,was wondering if maybe it could be an iron deficiency,any help would be much appreciated thanks in advance stef
your girl has a magnesium def 1 tabelspoon of epsom salts to a gallon of water water with this mix and foliar spray feed the leaves goodluck
I agree with Chimera. If your ph is off, you could have nute lockout. If you add epsom salts and correct your ph, it may result in an overdose of salts in your soil. If you can, get a better pH meter because the soil meter you have (which I also have) is useless. It doesn't read properly imo. Let us know what the pH is. Also, be careful not to overwater as it could also cause yellowing and drooping. It also might be helpful to know what type of soil you're using and if you've given it any nutrients. Also, imo your light seems kinda high at 32" from the plants. If you have good air circulation and the temps are low, you should be able to lower that light to 18". Good Luck
thanks to all who replied,i got a loan of a neighbours ph meter and it says the same as mine,tested it on another couple of things to see how wrong mine was but it's the same as theirs,compost is john innes no3 mixed with extra grit for drainage and perlite,been feeding a 7-7-7 solution to it,but not too much of it,i've also moved the light down to 2 foot,ventilation is poor as i'm growing in a wardrobe,so i just leave the door open a couple of inches,will sulphate of ammonia do for raising ph?thanks stef
dude you got to lower not raise, in a emergency use a little vinegar, however, you should get some ph up and down, plants can actually use it. Mix your down/vinegar with water and check it before applying it should read between 5.8 and 6.0. And for heavens sake stop feeding it for a couple of weeks.
sorry dude,typing error,i actually meant would sulphate of ammonia do for lowering the ph?it says 2.5 ounces per square yard will lower ph by one,or would i be better off with the vinegar remedy?i can't lay my hands on any ph up-down thanks
I've never had to use either to lower pH. However, I've read that vinegar works well. Perhaps you should trying search GC to find similar problems having to do with high pH. Also, before you try to fix the problem, make sure you have a good idea what it is to start with or else you'll end up creating more. IMO it doesn't look like nute burn, but rather a nitrogen deficiency possibly caused by improper pH, or, overwatering. What type of pH meter did you use the second time, soil or water. It best to use a digital pH meter and measure the liquid before watering and then the run-off water after. This site might help you, http://growfaq.marijuana.com/growfaq/ Good Luck.
Aquarium supplies will sell you pH up or down. They are OK for delicate fish, so will be fine for MJ.
This is a magnesium deficiency; not Iron, not Nitrogen, Not over water. Give them more Epsom like Ganja said. Oh and a ph of 7.0 should not give them any problems. However, your gauge looks like it is at 7.5 which could be a problem. Definitely use some vinegar lemon juice or some ph down to lower it to between 6.2-6.8. I don't know about that sulfate of ammonia.
I here that you have used john innes compost is this the stuff that comes in three stages 1,2,and 3 if so i was told to keep well away from that because the fert isnt organic and will probably end up killing your plants exp no3.
thanks again for the replies,i'd been following the advice of matrix in respect of trying to find out the problem before creating any more,so i've done nothing much with it,just watered it once with fresh rainwater,so now the new growth coming through on top is a nice green colour with no yellowing any more,but the leaves that were yellowing,should they go green again?or will they remain yellow?keepontoking,i wasn't aware that compost was no good,but thanks for the tip,dont think there's much i can do about it now as roots seem well established,though it is actually quite a mixture i have it in,i had like one seed i found in my weed,which i planted in miracle grow soil,not really expecting it to do anything,then it sprouted and grew some,so i repotted the root ball into some cactus soil and perlite with extra gravel,then when it outgrew that,it went in the 10" pot with the no3 john innes,so i guess i can only hope,oh and matrix,i got a fan in there and have managed to get the lights down to 18" and reckon i could go some more so cheers,i'll take a picture tomorrow and maybe someone could tell me if it looks any better,don't wanna do it during it's dark time thanks stef
Im pleased to hear you did nothing to your plant and Id also like to say there is a trend........ to much misguided blame on PH going around lately. a PH of 7.0 is only 2/10ths higher than the optimum PH and will not lock out nutes. this is not radically off. soil will always buffer that much and more, particularily if you add some dolomite lime to your soil when you mix it (something I reccomend everyone get in the habit of)
id stay away from epsom salt. i put that in my water and the leaves turned yellow on spots of the leaves. i stoped using it and the leaves that survived turned green again and the dead ones fell off. its all good, just dont overuse epsome salt. i was putting a tblspn of epsom per gallon of water and it jacked my whole garden up.