Is this nute burn or mag dif or..??
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I posted this same thread in indoor growing and didnt get any responses!



Check my pics out, this is happening on a few randon plants. its a soil grow, one for week for veg. ive been feeding with foxfarm big bloom, they have had 2 feedings, next one is thursday. water ph is 6.5, room temp is 83.

i posted last week, kinda of the same problems. however there wasnt the dark spots... my plants were yellowing and i came to the conculsion that they were hungry and it seems they are getting back to green, minus this new condition. the leaves in the pics are from the lower part of the plant.

I appreciate any help or ideas.

Thanks

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What is the pH of the soil runoff? I ran into a serious Mg and/or K deficiency problem in my soil grow despite adjusting the pH of my water/fert solution each time. It rapidly got worse and I was never able to get the soil runoff pH above about 4.5 (ouch!). I am foliar feeding for the last 4 weeks of flowering hoping to salvage the buds I have, but have learned a lesson about checking the soil runoff pH early and often (this was my first real attempt at an indoor grow).

My problems started out with little rust-colored spots on the lower and middle leaves about 5 weeks in (1 week after starting 12/12 for flowering), and quickly spread to all of the main stem fan leaves. I tried MgSO4 treatments (soil and foliar), leaching with 3x the pot volume using pH 7 distilled water, and nothing worked to get the runoff pH above 4.5. I still don't seem to have the problem under control but it is amazing how fast things go downhill if the soil pH is way too low.

do you ph the soil run off the same way as you ph your water. just fill up the little container and a drop of ph fluid to test or do i need a differant set up?

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I have a pH meter from Milwaukee that also does ppm and EC (very handy), but any good pH meter that works directly in the water should work. I just stick it into a calilbration solution (pH 7.01) before each test, then stick it in the runoff water I've collected.

I've never used the strips and color charts but don't see why they wouldn't work as well just as you'd use them for the normal tests of the water you're using for your regular watering. I thought that if I watered with pH around 6.7 or so I'd be OK at least for the first month, but my runoff is consistently in the 4.5 range now even after a thorough flush with pH 7 distilled water at 6 weeks, and I don't seem to be able to do anything about it. So I'm stuck with foliar feeding and plan to use a ProMix BX base mix next time mixed with 25% perlite and 25% vermiculite, along with enough powdered dolomite lime to get a slurry of this mix (in distilled water) at pH 6.5 - 6.7. Good luck, and I hope you don't have as serious a problem as I ended up with.

im using ro water and just found out that alot of the nutes are filtered out. so i was going to pick up some calmag from the hydro store and see what kind of ph meters they have.

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I was using distilled water with my nutes, and the nutes had no Mg or Ca. So even without the acidic soil that would lock these out I was depriving my plants and didn't realize it until it was too late. I found some magnesium sulfate at the local hydro store and thought that would help, but I was adding it to my normal soil watering and the pH was way too low for the Mg to get into solution for the roots to absorb. Foliar spraying with a more dilute solution of this did eventually help though.

If you can find a good digital pH meter it's worth the extra money. I got one of the cheapo Rapitest gadgets and it was a complete piece of crap (although a similar moisture meter from them seems to work OK).

If you can find a good digital pH meter it's worth the extra money. I got one of the cheapo Rapitest gadgets and it was a complete piece of crap (although a similar moisture meter from them seems to work OK).[/quote]

i myself bought both and have the same opionion about them. ill look for a digital meter.

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Week 1 is to soon to give nutr to the plant, you should wait at least 2 weeks if not 3, then start them slow with 1/2 strength nutrs. the first time./ water with nutrs every other time. Ph your water to 6.2(your soil ph should be 6.6-to-7---it should have dolomite lime in it to stabilize the ph. be careful not to over-water, let the first inch of soil dry out before you water-----use the cal/mag since you are on RO----leach the soil with 3x water -to-container size to flush every 4 weeks. good luck. note: If your soil ph is below 6 you will need to add enough dolomite lime to bring it up. if your soil ph is above 7 you should add more sphagnum peat moss to bring it down---------*********get your temps down to 78 and keep your humidity at 40%/make sure to have good airflow around plants*********

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thanks for the reponse. let me clear a few things up. i miss typed above, they are 5 weeks old as clones. tomorrow will be the 3rd feeding, im at half strength, foxfarm calls for 3 tsp im using 1.5 tsp. sunday i will put them in veg. i just got some calmag and used it yesterday for the first time. the digital ph combo tester that i want is 180 bucks, so i gotta look online.

now the part about leaching and flushing every 4 weeks. arew you saying to do that in flowering also. when i water i use a moisture tester and i always allow the water to run out the bottom of the pot. sunday before i switch them over to flowering i was thinking about doing a good solid flush or should i not and contiue on my same watering pattern, which is tues, thurs and sunday????

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1. I have been working with the foxfarm nutrients and they are hot(I don't mean as in temperature)- they say to use 2 teas of grow-big and 2 table of big bloom/gallon---If you mix them like that you will get a ppm close to 2000(way to hot for soil) That's with pure RO water and before you have used the cal/mag or any other add. What I do is mix everything just like they say( this will keep the nutr ratios right) then after all the nuts and adds are in, I will take a ppm reading and do the following:
from seed:
week 1 & 2----no nutr or adds just plain h2o at 6.3ph(couple drops ivory dish soap----has tiny amount of sulphur and helps wet soil)

week 3 -------nutr with every other water @250ppm
week 4--------nuts with every other water@600ppm
end of week 4 flush with three time h2o/container(1 gallon container gets 3 gallons of flush) since This is usually the time I transplant I will flush my containers with a 50% ratio of thrive alive w/B(organic sea kelp) 6ML/gallon this is also for stress. My ph for the flush is 5.8-6(the reason for this is the soil I used is very stabilized to 7ph with dolomite lime--if your soil has a lower ph raise your flush ph by the same 0.0%)
week 5---------no nutr just 6.3 RO h20
week 6 thru 10---------nutr with every other water @800ppm
end of week 10 flush same as end of week 4--------now ready to: 1. take cuttings----or 2. transplant into larger containers then move into flowering

the flowering cycle is pretty much the same-----I use foxfarm soil so the only thing I feed them is the thrive alive at transplant for week one, then on week 2 of flower I give them nuts and stims @1200 week 2
1300 week 3,4.
1600 week 5,6.
1300 week 7
then flush till ripe.

By the way--I had a blue lab ph and I hated it----it was the worst product I have every purchased---I took the damn thing back and got a Hanna ph/ec/ppm hand held and I have to say that I just love the damn thing so much----honestly-the thing stays within .1 of any setting and you can bounce from ppm to ec to ph with just a push of the button---the units are just killer-----the only thing I would have liked to have that mine didn't was the temp. Other than that I give the unit 5 stars*****

One more thing----The foxfarm nutr have mag in them so you might want to keep an eye out(you do need the cal when using RO but watch out for to much mag as well-----I use 2.5ml instead of the 5 per gallon(cal/mag) every time I water without any signs of magnesium toxicities. hope all this helps--------just remember-------------temp78/hum40/less is more on the nutr./dont overwater/plenty of airflow/use neem 2x week... good luck

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