Leaf Spotting on lower leaves; what does this look like to you?

[sy9942]

I'm getting this spotting on a couple plants I have in a bubbler (which itself contains 10 plants) and I'm curious what it looks like to you guys. I was thinking calcium deficiency but I'm not totally sure. I'm not getting this on any new growth, only on the fan leaves a few nodes down. Also, I'm not seeing this on all of the plants in the bubbler, just a couple.

Grow method: Hydro
Container Size: Holds approx 1.5 gallons of water+nute solution
Feeding Schedule: 2.5ml GH FloraMicro, 5 ml GH FloraBloom, 1/4 teaspoon Epsom Salts every Friday
Watering Schedule: Top-up with distilled water as needed
Age: 4 weeks this Friday
Strain: Unknown/bagseed
pH/EC/TDS: Unknown, meter recently busted and it will be a while before I get a new one.

Pics:

 

[dankiestog]

looks like u just need to flush...maybe salt bulid up....are it could be Cal Mg...

 

[Nape]

Hydro without any means of PH testing will be dificult at best. Atleast get some aquarium test strips, beats nothing.

 

[buddymag00]

Hydro without any means of PH testing will be dificult at best. Atleast get some aquarium test strips, beats nothing.

i agree my first hydro grow .without knowing your ph you are cruisin for a bruisin . your plants will be constantly shafted and you will be trying to fix it , and prob make it worse cause u dont know whats wrong ! youll see what we mean when you do get around to properly controling your ph.

 

[Blackvelvet]

I will guess potassium deficiency. The gh grow contains alot of potassium. Your
not using that.

Also, your adding epsom salts that are not needed. Gh requires none. Potassium, calcium, and magnesium all compete.

Your feeding too weak. At 4 weeks old, you should be using at least 1/2 strength. Full strength is 15 grow, 10 micro, 5 bloom per gallon of water. If you got 1.5 gallons and use 1/2 strength = 11.25 ml grow, 7.5 micro, 3.75 ml bloom.
This gives you about 100 ppm nitrogen. You can go up to 150 ppm n for extra growth. That would be about 3/4 strength. I doubt you will need full strength.

You must find a way to measure ph. Get some ph strips like suggested from a petstore in the aquarium section or a brew your own beer/wine store.

 

[blueberryfarmer]

Dude look the fuck out... i hope you can figure out what's causing this because i have the same problem, only way worse by now. I just started a thread a couple of days ago: http://www.icmag.com/ic/showthread.php?p=854225#post854225 and basically from what i can tell mine are/were being underfed. But i fertilized them again with little effectiveness.... The lower leaves have all yellowed and spotted like that and died off, and its working its way quickkly up to the upper fan leaves. If it doesn't stop my yield will be severely reduced, or the plant will die... its just starting week 3 of flower. Curiously, my other plant is barely affected by this at all... for details and pics see my thread. The pics underestimate the problem at this point, as its gotten worse since. I think you might be right in that the spotting is a result of calcium deficiency.. The yellowing and whatnot on my plants may be the result of other deficiencies... I just bought new FoxFarm ferts and perhaps they need to be mixed higher than recommended. Anyway, hopefully you can test the pH of your solution.. If thats not it then i'd say definately calcium deficiency.

 

[sy9942]

I will guess potassium deficiency. The gh grow contains alot of potassium. Your
not using that.

Also, your adding epsom salts that are not needed. Gh requires none. Potassium, calcium, and magnesium all compete.

Your feeding too weak. At 4 weeks old, you should be using at least 1/2 strength. Full strength is 15 grow, 10 micro, 5 bloom per gallon of water. If you got 1.5 gallons and use 1/2 strength = 11.25 ml grow, 7.5 micro, 3.75 ml bloom.
This gives you about 100 ppm nitrogen. You can go up to 150 ppm n for extra growth. That would be about 3/4 strength. I doubt you will need full strength.

You must find a way to measure ph. Get some ph strips like suggested from a petstore in the aquarium section or a brew your own beer/wine store.

I've been using half-strength Lucas formula. Lucas formula is 0-5-10 (Grow-Micro-Bloom ml/gallon), I'm using 0-2.5-5. I don't think I'm feeding too weak because I'm not dumping the res on a regular basis, I'm letting it accumulate as per a technique pioneered by NIMBY on Overgrow. I will find a way to measure pH this weekend.

 

[Jesusbuiltmygro]

Yea if your meter is broke you really need to get a chemical test kit or something. You need to know the PH. You can pick one a nice Hanna meter for 60 bucks.

You can grow without meters, but it probably not a good idea and your not learning much when your not using a meter since your don't get to see the actual numbers changing but rather you have to guess.

Usually with PH it's because the ph is too high and this is far FAR more common than deficiency. Since you don't have a meter it hardly matters how one plant is doing vs another because they are in seperate rezes. Every plant uptakes at it's own rate depending on lots of things including genetics, so the PH and PPM of one container can very well be signigicantly different than another.

DWC is a prone to root rot and PH fluxuations so you really should get a meter and be monitoring the rez temps. If you have the motivation you might want to start cooling DWC rez or at least measure the water temps.

Flushing is always a good idea in DWC because of harmful bacteria buildup and salts also, but mostly harmful bacteria.

Seems to me calcium deficiancies are pretty rare unless y=our using RO water. Most of the time things that appear to be calcium def are usually nutrient lockout caused by PH.

You'd probably be better off not using distilled or RO water as Big Toke recommend in his water chemistry thread. If you haven't read that already then you need to.
Tap water has a higher PH, but that shouldn't matter if you are using buffered nutrients which are designed for tap water. Most nutrients are made for tap water, so using them with RO / distilled water is just asking for trouble. Tap water has extra calcium and magnesium in it and a much more stable PH.. however the PH will tend to swing toward the PH of the source water usually around 8+ but the nutrients should bring it back down to 6-6.5 which requires little PH adjustment if any but because tap water has PH biffering the PH will likely stay around that PH longer which is usually better for the plant. PH swing can be somewhat good, but it's not how things happen in nature and too much swing is definately stressful to the plants.

Most full range nutrients simply have everything you need to grow plants without deficiencies, so that's why I usually learn towrard PH being the problem.

Wow 10 plants in a one bubbler... I'm sorry for you. Do yourself a favor and don't do that again. You basically shouldn't grow more than one plant per bubbler unless you like losing your plants to root rot.

If you keep having problem I'd suggest using tap water or for the sake of ease go with a tap water/distilled water mix. I'd recommend spring water over distilled water BTW because it does have some minerals which you plant will like.

Having water with a very low PPM is entirely useless and overrated. I went this route with a 5 stage RO filter once but it was because my tap water PPM was over 600. If your PPM out of the tap are under 250 you should probably use your tap water. Remember to leave it sit out for at least 24 hours though to let the chlorine escape if you are on city water. Plants are not that sensitive to PPM so it really doesn't matter if you water starts at 200 PPM. If you grow with organic nutrients PPM matters even less.

The fastest way to reverse deficiencies is to foiler feed. A good seaweed/kelp solution is a great start for foiler feeding deficiencies away. Check your roots and make sure there is no slime and that the water doesn't smell like swamp water or just bad in general. Roots should be white. If your roots have brown slime in it then you will be battleing root rot. If your using chemical nutrients adding h202 with your top off may be a good idea. The more plants you have the greater chance you will develop root rot and since they are all in oen container it will not take long until they are all affected. Adding air stone may also help, but flushing is probably the only reliable thing you can. Some people flush as often as every 10 days. Keep in mind flushing will not kill root rot or other harmful bacteria. It will just help you control it. H202 will kill it, but usually not all the way. H202 is more like a way to keep it in check or prevent it from developing in the first place.

I personally use organic nutrients with a beneficial bacteria approach to hydro. I've used h202 to battle root rot in the past in DWC. But now that I have a bacteria driven hydro system I don't need it.

For good info on hydro just think about how aquariums work. They say to flush every 2 weeks, but I run my aquarium for months without a water change. Why can I do this? Because I have a bio-filter and just the right amount of water and fish. The fish poop is eaten by bacteria instead of breaking down and adding harmful amonia and nitrites to my tank which stress and kill the fish as they buildup.

Your DWC Is more like the old school approach to aquariums in which you constantly rely on water changes to keep the balance, but the new approach which it quickly taking over is to incoporate biological filters which basically keep the bacteria ecosystem in balance. You should switch next grow IMO. Even something like a bio-tub would be much better for you and reduce your chances of root rot and nutrient lockout from PH as the beneficial bacteria also help with nutrient uptake. So they not only keep your res from turning to slime, but they increase growth and they make it so your PH can be higher without nutrient lockout problems. Pretty awesome stuff. If your not growing with a bio filter of some type you are missing out.

Bio filters work best with flowing water.. think stream. Nimby has the simplest design in his Biotubs which require no plumbing. I haven't used one yet, but several other people have. I fear the higher temps caused by a submersible pump, but Nimby seemed to have no problem. I prefer the bio buckets, but they are considerable investment in setup. Anything with a biofilter is likely to produce similar results.

OH a biofilter is nothing but a place for bacteria to colonize. It can be made of any material that is easy for bacteria to live on... which from my understanding is pretty much anything. There is a common misconception that some materials are too hard or dense for bacteria to colonize, but I find this HIGHLY unlikely and even if microscopic bacteria couldn't penetrate a clay ball it would still colonize the outside. Just like it will also colonize the sides of your plastic rez. I know this is a misconception because I've look at other biofilters. Most of them are plastic which is not a pourus materia.

It's all about creating lots of surface area for your bacteria and idealy keeping that bacteria as close to the rootzone as possible. Thingsl ike lava rock create more surface area per volume of space it takes up. The plastic bio-balls and other devices can create even more surface area per given volume, but laval rock is cheaper and easier to get. I recommend keeping the medium for the bacteria to grow as close to the root zone as you can.

Also get yourself some rapid rooters if you don't already have some. Maxicorp is a great way to fight of deficiencies as a foiler application or right into rez, but def foilier is better however most people don't foiler feed once in veg.