Feeding problems in flowering

[regrat]

Hi.

I am always running into problems in second half of flowering and I cant seem to figure it out. It's been bugging me grow after grow and I'm getting pretty desperate.

I'd really appreciate it if someone experienced took the time to read my post and help me diagnose the problem.

I am growing in soil with added lime for stabilizing ph.
I have 400w HPS.
The plants are growing in 12L pots.

Plants were vegging for about a month, then switched to flower.
Up to about a month into flower, everything is looking more or less peachy. Here, I noticed slight discoloration/yellowing, pics:

http://img541.imageshack.us/img541/9936/72480377.jpg
http://img42.imageshack.us/img42/4677/82601997.jpg

So, I fed them 0.4 EC dose of maxibloom.
-my tap water is at 0.25EC
-full dose (7 grams per US gallon) comes at about 1.45EC

After not seeing any improvements and following an advice from fellow grower, I fed them again next watering, upping the dose to 0.5 -0.8 EC (depending on the plant).
This is the result a week after:

http://imageshack.us/a/img228/4917/62801276.jpg
http://imageshack.us/a/img201/126/60804571.jpg
http://imageshack.us/a/img833/472/47389732.jpg

Strangely, the plant I fed the least (0.4EC + 0.5EC the second time), is showing burned tips, while the two plants I fed 0.8 EC are staying the same or just yellowing more.

At this point, I watered them with plain water.
I'm really not sure what to do from here on.

Please help.

 

[ZZTops]

Looks like a Cal deficiency to me, 3ml of cal-mag ( or like ) per gallon should help out...

I have found if you change a plants routine they do not like it, so when it got less it reacted...

I just went thru this with some AK-47 I was running...

4 weeks into bloom and I was feeding every four days, missed one feed as I was out of town and thought no big deal. Well it was a big deal as 20% of the plant yellowed/rust spots/edge browning when I returned...

Two feedings with Cal-Mag and things turned around, there is a tad of Nitrogen ( .01% ) in there so do not over do it...

 

[BullnAChinaShop]

Is your soil amended with anything but lime?

 

[regrat]

http://imageshack.us/a/img833/472/47389732.jpg

so, do you think that in this pic, the plant in the bottom right corner that looks like it's burned, could be something else than burn ? this one was fed 0.4EC and then 0.5EC next watering. to me it seems like a burn but its odd, since i fed her such mild dose.

and no, i only have a bit of lime in soil, nothing else.

 

[BullnAChinaShop]

They look hungry to me. 2 half feedings at this stage of flower with only maxibloom is just not enough imo. If you are feeding maxibloom why not just switch over to coco and put all the madness behind you? This is what I did and haven't looked back.

 

[joe fresh]

just a thought, dont post immages on immage shack, easy to trace you...much better to post em here on icmag

 

[Sat X RB]

Is your soil amended with anything but lime?

wundrin if yr soil is bought or made by yrself?

seems to me most if not all purchased soils are amended ... because there can't be enuf natural soils around anymore that are good enuf. I mean imagine how huge the soil quarry must be to keep we gardeners going. the good stuff must have been mined long ago so what we get now is amended ... and unknown soil amendments can screw up yr feeding regime.

I 'm tending to a shortage of N (yellowing) and possibly Ca (spotting) as there is often a demand for both these minerals at flowering.

perhaps you could foliar spray N (Urea ... instructions usually on the pack) to find out if it's N. obviously foliar won't upset yr soil and possibly make things worse in the long term ...

and a LIGHT sprinkle of Dolomite on top of yr soil and water in will supply Ca and Mg. but make sure it's a light sprinkle.

cheers!

 

[regrat]

my soil is bought and it's supposed to be one of the better soils you can get, some of the best growers from my area recommend it.

i've decided to feed a full strength to 2 or 3 plants next time i'm watering.
i'll report back.

 

[regrat]

its a disaster. after feeding 3 plants a full dose, things are a lot worse. i dont know, i fed them all kinds of doses from 0.4EC to 1.35 and none of em worked out.

next grow im gonna go with 30L pots and maybe some biosupermix added so i wont have to fertilize and thats it. hope at least that works out.