Newbie: Yellowing leaves

[bingoMadness]

Heya kids!

 

Bit of a newbie here today, and a newbie at growing too!

 

I'm working on my first few plants and things seem to be going pretty well. However recently I've been getting some yellowing of some leaves, particularly on new growth. I'm a bit stuck as to what exactly the cause could be and I'm hoping someone may be able to help out.

 

Current setup/situation:

3 plants grown from seed.

Closet setup with a 400W HPS lamp, foil on walls two fans (one in, one out).

18/6 hours light.

Plants seem to be getting dry every day or two now and I've been watering them as such (too much?).

I've been using some fertiliser called "Charlies Carp" with most waterings (too much?).

 

From my research I've considered Nitrogen deficiency but due to the fert I'd guess this isn't the case. Magnesium deficiency seems to also cause a similar problem so I'm a bit sus on that too...

 

All going well (my first post) I should have attached a few photos to help with any diagnosis that a generous member may help me out with! On the zoomed out view I've circled where the yellow leaves are growing, which is at the point of new growth on a couple of the plants. The other pic shows a close-up.

 

Any help anyone can provide me with would be greatly appreciated!!

 

 

[F420]

How far away is the light? too much light can cause yellowing, although a 250 shouldnt be a problem.

 

YOu can try a using a little epsom salts against Mg deficiency.

 

I wouldnt be too worried though unless they are dying, A plant can do weird things for no reason like yellowing.

 

You could also try something like Dutch master MAX to keep them green.

I would ditch the foil and use panda or on your next grow paint the surfaces flat white.

Foil is something that shouldnt be used, it can create hot spots on plants.

 

my gut feeling is that they are too close to the light and is starting to burn or leech the Chlorlyphyl out of the leaves.

 

most overwatered plants that I have seen actually go darker green. but make sure the top inch at least is dry when you water.

WHich brings another point, what is the PH of the water your feeding them? PH of the soil?

 

 

Anyone else??????

[bingoMadness]

Thanks for your ideas Ferengi! :thumbsup

 

The light is actually a 400 watt HPS. I too was a little suspicious that it may be too close and burning the plants even though I was carefully checking to make sure it didn't feel more than a little warm at plant level. In any case I did move the light up about a foot higher a little while back and it didn't solve the problem.

 

Overall the plants seem happy enough so I'm not too worried as long as I don't seem too much more of it.

 

Thanks for the tip about the foil! I'll have to watch out for that and improve next time. But what's "panda"? Is that the reflective plastic sheeting stuff I've seen?

 

I have been making sure that the plants are pretty dry before watering, so it sounds like over-watering isn't the problem.

 

I don't think I mentioned it in my original post, but I too am concerned about PH levels. I don't have anything to test this with yet so I think I'll have to pick up some kinda PH test kit very soon.

 

I also want to try some other fertiliser to see if it can help. The "Dutch Master MAX" stuff you mention... is that easily available locally or an import job? If not easily available in Australia, anyone got any suggestions of a fertiliser that is and that works well?

[F420]

The light is actually a 400 watt HPS. I too was a little suspicious that it may be too close and burning the plants even though I was carefully checking to make sure it didn't feel more than a little warm at plant level. In any case I did move the light up about a foot higher a little while back and it didn't solve the problem.

 

yea, thats the best method. just make sure that your testing it in the middle of the hottest part of the day and your fans are turned off to do the test.

 

But what's "panda"? Is that the reflective plastic sheeting stuff I've seen?

yeah its that plastic stuff thats white on one side and black on the other. it comes in 2 thicknesses one you can see light through and the other is twice as thick and you cant see light through it. paint works just as good if you can paint it and leave it for a couple of weeks to dry.

 

 

I don't think I mentioned it in my original post, but I too am concerned about PH levels. I don't have anything to test this with yet so I think I'll have to pick up some kinda PH test kit very soon.

Yea, its always best to have your PH levels right 5.3 to 6.6 is good. tap water is usually around 6.8 to 7.3 approx and as such needs a little PH down to adjust it correctly.

Buy a PH tester and something to bring the ph down.

 

http://67.15.70.25/dutchmaster.com.au/admin/library/library/Chart.jpg

 

I also want to try some other fertiliser to see if it can help. The "Dutch Master MAX" stuff you mention... is that easily available locally or an import job? If not easily available in Australia, anyone got any suggestions of a fertiliser that is and that works well?

 

Dutch master is a scam of a name really, its all made in Australia.

 

MAX isnt a nutrient, its an additive to your nutrient.

Max’s performance is based on Humatic Isolate technology, a revolutionary & natural way to aid plant performance.

but basically its keeps the plant greener.

www.dutchmaster.com.au

 

As for nutreints like A+B, dont get too hung up on names etc, its all the same shit, so any nutrient desinged for MJ will work.

Dutch master is a good brand though, I used it a few times and got good results.

 

My current brand is pretty good, Im using Amsetdam indoors for veg and Experts choice for bloom.

[Luke Skywalker]

I'd say it's likely a micronutrient deficiency, Mg or Fe probably.

 

Try getting a better, soluble nutrient for growth, MJ is a greedy bugger when it comes to nutes and it really likes a good amount of Mg and other micronutes in comparison. Of course don't overdo it, but you can probably get a better result by using a more soluble, balanced out fert, and ensuring that pH is adjusted as tom remarked.

[bingoMadness]

Thanks for your feedback Skywalker.

 

Since my last post the tips have greened up good and overall I think the plants are doing quite well now.

 

I've recently picked up a PH test kit, which showed my water at around PH 8... so I think adjusting that down has helped the plants absorb the nutes

 

I've also got some good nutrient mix that I think is better suited to MJ's needs including micro nutes etc... and I've started folier feeding to keep 'em going strong!

 

But thanks for your post! Appreciate.

[F420]

Be very careful foliar feed MJ, and especially under lights.