Help with yellow leaves!

[gweenfingers]

Anyone got any ideas about this. The plant is about 18 inches high and 2 months old. Most of the leaves and all of the leaves at the top are lush green but some of the leaves from the bottom of the plant and up to about two thirds up are going first yellow and then brown and crispy from the tip of the leaf working back towards the stem. Would appreciate any thoughts!

[Mr. Clandestine]

You're still in veg? If so, have you been using any supplemental fertilizers? Also, 2 months in veg can mean a large plant... is it possibly rootbound? It looks like a N deficiency, but without knowing more about the plant, it's hard to say what might be causing it.

[gweenfingers]

The plant is ppp and its grown indoors. The plants are all about 20 inches high and fairly bushy. I dont think they are rootbound as the pots are fairly large about 10 inches high by 12 wide. I am using miracle gro and I had thought about nutrient deficiency but one of the plants has grown without feed and is the best of the 4 without any yellow leaves. Thanks mate!

[gweenfingers]

I am also using tap water but I have heard something about the chlorine and calcium levels causing problems. Could I use rainwater and would this help.

[Mr. Clandestine]

I wouldn't use rainwater, since rain generally picks up all sorts of impurities and salts on the way down. If you're truly worried about chlorine in your tap water, you could fill up a pot and let it stand at room temperature for 24 hours, which I hear is enough time for the chlorine to evaporate out. I don't think it's your water that's causing you the problems, though.

I'd start with a light feeding for the plant that's showing the worst signs of yellowing using a high nitrogen fertilizer. Start weak (1/4-1/2 strength) and work your way up until you notice a difference. Your other plant may not have used up its last nitrogen reserves, and is why it's not showing any signs of deficiency. I wouldn't feed that one just yet, but it wont hurt to feed any that may be yellowing.

Hope that helps. :jointsmile:

[gweenfingers]

ok mate... thanks I'll give it a try.

[stinkyattic]

Rainwater? Often too acidic, will use up all the lime in your soil, drop the pH, and lock out nutes.
For your N feeding, I'd go with an organic fish emulsion supplement, which will not only give much-needed N, but also help buffer the soil. You still need to give regular feedings with a fert that has micronutrients in it.