sick plant.. magnesium def?

guyson · Mar 7, 2011

my plant looks like it has a magnesium defeciency, however, could it be either a nutrient lockout from the levels of the ph in the water, or to do with letting the water sit overnight making the water lose the magnesium from it?

information you might need to know:
biobizz all mix - says ph level 6.2 on the bag.
250w hps
extractor fan
heat and humidity seems okay
and i have no ph pen to check the ph levels, however i've never had a problem before, using the same methods growing.
feeding hesi nutes, however i'm feeding each watering with water been left to sit at just 1/2 strength.. could feeding at full strength help to solve the problem - hesi does contain calcium and magnesium so is it thats it's just not getting enough?

i also looked on the severn trent water website, and the information it has gave me for my post code, is the ph levels of the water are at 7.48. if my water needs ph adjusting, is there anything you could do to figure out how much of something i could put into 2L of water to lower it by 1? would i need to adjust the waters ph each time i feed the plant, because in my previous grows i've had problems but they seemed to have gone away, and have never had problems with ph before!

if i remember rightly, it does seem to be the middle leaves affecting first, and then the newest leaves after (the newer leaves starting by going a lighter colour at the tips of the leaves, slowly getting worse from there.)

congoz · Mar 7, 2011

full dose of hesi food will be around 800ppm and wont be too much for this plant but i believe she needs extra cal-mag too.

you need a ph and tds/ppm meter.

guyson · Mar 7, 2011

cheers mate, where can i pick up cal-mag from? would you say my ph levels from tap water are okay, and is it best to use water been left to sit or water straight from the tap?

hellraizer30 · Mar 7, 2011

if your thinking its a mag/nitrogen lock out them start a flush. then mix 1/2 nutes and work up from there, to me it looks like a
nitrogen DEF. and Il bet it started as soon as you went into flower. not having a PH pen would exsplain the lock out!! you need
to get a PH meter/pen

guyson · Mar 7, 2011

i'm still in vegging at the moment with vegging nutes, but i did put the plant into flower for a week to show its sex. i did flush not long ago, and then put back on half strength nutes, because i had same problem then. but even after the flush, and after putting the plant back on 1/2 strength nutes i havent noticed much difference.

i'm hoping to get a PH pen asap but for now i have no money to get one. i'm thinking if this is just a deficiency, then until i can get cal-mag would hesi supervit help out at all? i have it but have never used it.

hellraizer30 · Mar 7, 2011

not sure of those nute brands but if it has a higher Nitrogen then add some little by little and watch the new growth! the old yellow stuff wont
come back so dont judge it by that.

guyson · Mar 7, 2011

i'm not entirely sure, it says on the bottle label that it contains 25 different elements in for vital plant growth. it contains 15 vitamins and 10 amino acids so i guess that will make no real difference. would upping the strength to full at next feed be worth a shot if i watch the new growth carefully?

hellraizer30 · Mar 7, 2011

I never use the full strength recamendation on any nute brand, what the N/P/K number on the bottle

congoz · Mar 7, 2011

you should be using hesi tnt for vegetative grow and 50ml for 10lt of water gets around 800ppm and its N high fertilizer.

flushing the soil rinses all the magnesium.

Snow Crash · Mar 7, 2011

The ratios are off here. You need more pk and mag, less calcium, and a lower total EC in the media. Flush the system first. Then use less of your standard macro nutrients and include like 1ml of a pk booster and/or magnesium supplement. You are high/low with the nutrients and it is better to just be at the "Goldilocks" zone where they are just right.

Focus on a lot of run off as you go on in the future. Always remove the run off from the drain tray.

Every else is correct in suggesting a pH meter as well. Probably contributing to what is clearly a much more complex issue than simple mag deficiency.

guyson · Mar 7, 2011

the NPK for hesi is 3,2,3. i'll be getting a meter in a couple of weeks, but for now i need to try and get by without. i've heard that if tap water is ph adjusted before you feed it, then the ph should be fine? i've figured out that 3.3ml of lemon juice to a gallon would bring ph down from 7.4 to about 6.7 if i got my calculations right. could it not be the ph of my tap water? (7.4) i've never experienced problems before when growing and i've used the same tap water, soil, techniques, nutrients etc. so why im confused is why i need more of some nutes, less of others?

Snow Crash · Mar 7, 2011

During flowering, from the end of the second week onwards, the plant is building flowers and not leaves. As a result the plant requires a different ratio of nutrients. Phosphorus helps build flowers.

A better ratio would be 1-3-2. If you can dial back the 3-2-3 and add a high P, lower K, bloom supplement you'll have a healthier plant. Your plant is showing a variety of symptoms which always points to pH issues.

You are estimating things with no real idea of what is going on. Also, you have no idea how acidic the nutrients are. Also, you probably don't need any pH down at all. Also, you always pH balance after adding nutrients.

guyson · Mar 7, 2011

the thing is, my plant isn't budding yet, its still on 18/6, so why would it require different ratios of nutrients? i have biobizz bloom and topmax for when i switch to flowering too.

so whats my best bet until i get a ph meter because like you said guessing will get me nowhere. another interesting thing i've noticed is its mostly fan leaves affected, on the main branches etc. the leaves are green and healthy!

Snow Crash · Mar 7, 2011

I'd made my assumption based on this picture:

1480548d1299530498-sick-plant-magnesium-def-dsc01335.jpg

You should give information like that in your OP to help people help you...

The problem is that there's all kinds of stuff going on. You need to flush the media to ensure it is clean and without buildup. Then you can run whatever you want to run.

hellraizer30 · Mar 7, 2011

Snow Crash said:
I'd made my assumption based on this picture:

You should give information like that in your OP to help people help you...

The problem is that there's all kinds of stuff going on. You need to flush the media to ensure it is clean and without buildup. Then you can run whatever you want to run.

yah that pics where I based my info off of to maybe a new more current pic would be great!!

guyson · Mar 7, 2011

should i get some more pics up of the plants leaves then?

cheers for the help everyone, appreciated!

hellraizer30 · Mar 7, 2011

would be a good idea please do

guyson · Mar 7, 2011

i've attached some more pics. the leaves have got the brown spots between the margins and the yellowing starts from the tips inwards as you can see.

hellraizer30 · Mar 7, 2011

well im sticking with nitrogen def. there might be something elde going on. when you flowered to sex them the def. showed up and now your in veg and this issue hasnt
cleared up but your newer growth looks better, start adding a nitrogen sup. could be a mag issue to

guyson · Mar 7, 2011

cheers mate, what does the brown spots between the veins look like? i've been feeding at half strength nutes, shall i carry on as normal and see how it goes, or flush the plant and start giving nutes again?

sick plant.. magnesium def?

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