leaves turning light green with pics

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mikethegrower

Active Member
My leaves are turning a light green color. This is mostly happening to the topmost leaves but on a couple plants it goes down further. It is only happening to a few of my plants and they are all in the same room with no difference in light, nutes, water.
They are in pro mix,perlite, sand mix and are about 12-14 inches from my 600w mh with air cooled hoods. They are about 5 weeks old. I have ruled out overwatering(I let them dry right out) and too close to the lights. Temps are good, 75-80 day and 70-75 night. Hope this is enough info. Thanks
They look quite a bit lighter than pics show. Also one pic is of healthy plants
project 001.jpgproject 004.jpgproject 008.jpgproject 010.jpgproject 013.jpgproject 014.jpg
 
LUDA

LUDA

New Member
mikethegrower said:
My leaves are turning a light green color. This is mostly happening to the topmost leaves but on a couple plants it goes down further. It is only happening to a few of my plants and they are all in the same room with no difference in light, nutes, water.
They are in pro mix,perlite, sand mix and are about 12-14 inches from my 600w mh with air cooled hoods. They are about 5 weeks old. I have ruled out overwatering(I let them dry right out) and too close to the lights. Temps are good, 75-80 day and 70-75 night. Hope this is enough info. Thanks
They look quite a bit lighter than pics show. Also one pic is of healthy plants
View attachment 2379888View attachment 2379889View attachment 2379890View attachment 2379892View attachment 2379893View attachment 2379894
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I don't know the NPK values of your feed but it could be a simple case of a lack of nitrogen or a slight magnesium deficiency. Otherwise they look great.
 
Slipon

Slipon

Well-Known Member
Ca/Mg is the fist thing that springs to mind ..

Epsom salt from the local wellness shop or some Ca/MG + from the hydro store ..
might want to grab some Dolomit Lime now your at it ..
 
M

mikethegrower

Active Member
Slipon said:
Ca/Mg is the fist thing that springs to mind ..

Epsom salt from the local wellness shop or some Ca/MG + from the hydro store ..
might want to grab some Dolomit Lime now your at it ..
Click to expand...
I just repotted from 1 gal pots to 5 gal pots last week and I added 5 tablespoons of dolomite lime to each pot.
 
LUDA

LUDA

New Member
Actually, you can almost use any fertiliser, but the nitrogen content should be proportionately high, and there should be
some P and L also present. For example, a 20-20-20 would work fine, as would a 12-6-6 or a 3-4-3, but not a 2-10-10
or a 5-10-0.
How much fertiliser to use and how often to fertilise depend primarily on the fertility of the soil and the size of the
container relative to the size of the plant. Small plants in large pots usually do not need to be fertilised. Even in small
pots, most plants do not need to be fertilised for at least the first month.
As the plants grow, they take nutrients from the soil, and these must be replaced to maintain vigorous growth. During
the vegetative stage, even plants in large pots generally require some fertilising, particularly with N.
The rate of growth of indoor plants is usually limited by the amount of light and space, once adequate nutrients are
supplied. At this point, an increase in nutrients will not increase growth. Your goal is to supply the plants with their
nutritional needs without overfertilising and thus toxifying the soil.

(By M+E)
 
scragelynugz

scragelynugz

Well-Known Member
I would still check your overwatering dude. Those leaves look plump and heavy. Stick your finger all the way into the soil and wait to water until its almost dry. Whats your pH? this is more important than what nutes you have it on? Soil is 6.8 ideal

Oh, and you added lime but not Sulfur (epsom salt). This could make your pH very basic and lock out Sulfur. (again, check your pH)
 
LUDA

LUDA

New Member
scragelynugz said:
I would still check your overwatering dude. Those leaves look plump and heavy. Stick your finger all the way into the soil and wait to water until its almost dry. Whats your pH? this is more important than what nutes you have it on? Soil is 6.8 ideal

Oh, and you added lime but not Sulfur (epsom salt). This could make your pH very basic and lock out Sulfur. (again, check your pH)
Click to expand...
I cant say that's anything to do with watering and a PH of 6.5-6.6 is ideal.
 
M

mikethegrower

Active Member
My ph is 6.4 when I am watering. I'm not sure how to check soil ph. I tested the first bit of run off when I watered yesterday and it was 6.8. My soil was completely dry before I watered. 8 days between waterings. I see a lot of different ways to check soil ph. I was going to go get some distilled water and mix in some of my soil with it and check it with my ph pen tester. Is this a good method? Thanks
 
LUDA

LUDA

New Member
mikethegrower said:
My ph is 6.4 when I am watering. I'm not sure how to check soil ph. I tested the first bit of run off when I watered yesterday and it was 6.8. My soil was completely dry before I watered. 8 days between waterings. I see a lot of different ways to check soil ph. I was going to go get some distilled water and mix in some of my soil with it and check it with my ph pen tester. Is this a good method? Thanks
Click to expand...
The run off should always be lower than the soils actual ph. How are you testing it at the moment. ?
 
LUDA

LUDA

New Member
  • Measuring the pH of soil is just as important as with hydro applications, but few people know how to test soil pH to see if it is within the optimum range for growing robust healthy plants. Here I will try to explain my method of testing any soil / soilless mix, enabling me to spot any problems and correct them if necessary.

    Firstly, wait till your soil has dried out and is due for its next watering schedule. Then take some plain water that you usually water your garden with, and adjust the pH to 7.0. You must make sure that you know the exact pH of the water going into your soil, and the neutral 7.0 is best, but anywhere from 6.5 – 7.0 will suffice.

    Then place your pot into a bowl of some sort to catch the runoff water, and then start to water your soil slowly (with your pH- corrected plain water) till the water starts to drip from the bottom.
    It’s the first drops of water that will give you the best reading of your soil, so make sure to water slowly till you see the first droplets. Then remove the pot from the bowl to eliminate excess water entering the bowl. Then perform the pH test on the runoff and compare it too your initial test.
    The results of the runoff test will likely be lower than your starting value of 7.0. If this is the case, a small drop of 0.5 pH to 6.5 pH (example) would be ok and your soil needs no further alterations at the moment. But that’s not to say that it won’t need any future tests at all, just not at this time.

    [Editor’s note: It may be beneficial to obtain an initial sample, as well as a ‘full flush’ sample in seperate bowls. In addition, test several plants in the garden just to verify your results]

    What if the pH is off?
    If your results prove to have dropped considerably, say to around 5.5 (which can happen in late stages of flowering), you will need to add some lime into your soil to help buffer the pH back up again.

    Remove the first inch or so of soil, taking care not to damage any roots whilst performing this task. Then sprinkle the lime into the pot, nice and evenly at a rate of 1 teaspoon (5 ml) of lime per gallon of soil. Then replace the soil you removed earlier, and saturate the soil good to wash in the lime.

    Do the same test next time your plants need watering just to check that everything is fine, if more lime needs to be added then just repeat the process again till you reach close to 6.5 – 7.0 with the runoff.

    Ensuring that your pH is correct should be done throughout the life cycle; this will help eliminate any nutrient lockout that may occur. I recommend doing this once a month just to keep the PH in check, and you should never have a problem with deficiencies caused by pH lockout.​



 
M

mikethegrower

Active Member
Update. I was working in the garden this morning and noticed that the light above my really healthy plants looked a different color so I got out my light meter and did a check. Turns out that the the light hitting the canopy was way lower on that light than on the lights that were above the plants that were turning yellow. That explains why all the plants under some lights were doing great and all the plants under some other lights were turning yellow. Raised all my lights so I hope that has fixed the problem. Now I just have to find out if it is a faulty buld, ballast or fixture. Hope this helps anyone else with a similar problem. I had the lights about 10 in away and the temps were ok because of the air cooled hoods but I guess it was just too much light.
 
S

smillz

Member
It isn't nitrogen, because nitrogen works from the bottom of the plant upward, not from the top downward. The plant will consume the oldest leaves for nutrients before attacking the youngest growth. I believe Ca/Mg which was said earlier is the most likely case.
 
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