help with dying plants!

[cannabis420]

I'll start with my set up first. 400 watt hps 12/12. Plants 12-17 inches away. Put them into flowering 6 weeks ago. first 4 weeks i gave them multipurpose plant food. (miricle grow) I gave them too much of that i think. the last few weeks iv'e been giving them tiny amounts of Age Old Bloom nutrient. plants are all 1-2 feet tall. I water about 1/4 of a liter every 2-3 days. I enhance the co2 by mixing yeast, water and sugar. I also changed the light from 75% power to 100% power a few days ago. let me know if u need more info.

There are a few different problems i have with a few plants.

- 1 plant looks like its in the veg state still even after 6 weeks of 12/12 lighting.
- 3 plants have yellow spots in the middle of the leaves. the leaves are curled a lot so the top of the plant has an umbrella shape to it. the leaves are very yellow and on 1 a bit purple. they started to yellow more from the sides of the leaves not the tips.
- this is my biggest concern. almost all my plants have started to turn a yellow then golden-brown color with the leaves also curling. My biggest plant has already died like this and i dont want my other plant to have the same fate.

thanks for any help in advance

[jackel]

try flushing them with plain water then letting them dry out. whats the temps in your room?

[cannabis420]

idk wat the temp it is but it shouldnt be to hot for them. to make sure i turned the power to 75%. could this b caused by the ph levels being to high or the lower part of the soil being to wet for an extended period of time?

[jackel]

im not understanding how ur turning the power down on ur lamps. can you explain this? because iv never seen a ballast that you can adjust how much power its getting.

[cannabis420]

its a 400 watt lumatek electromic ballast from hydrofarm. i got it at this AMAZING hydroponics store here in albuquerque, New Mexico. its a growers heaven. it has a 4 setting switch. 50% 250watts, 75% 275watts, 100% 400watts, and a super lumens switch(10% more light).

now im pretty sure i know wats wrong with my plants. they have root rot caused by pythium caused by overwatering. i read that hydrogen peroxide could help. is this true? any other remedies for root rot?

[jackel]

use a VERY diluted concentration. like a 1/4 teaspoon per gallon. its not a garentee the plant will live, but its better than nothing.
make sure ur pots have adaquete drain holes, and ur soil has enuff drainage to it as well.

[cannabis420]

well i put some more holes in the pots and went to the hydroponics store. they recommended Aquashield so im going to try that stuff out and hopefully it works.

and i didnt give my plants peroxide cuz i guess it kills both good and bad bacteria leaving the plants defenseless

[brandylorton]

well i put some more holes in the pots and went to the hydroponics store. they recommended Aquashield so im going to try that stuff out and hopefully it works.

and i didnt give my plants peroxide cuz i guess it kills both good and bad bacteria leaving the plants defenseless

Here you are absolutely right regarding the bacteria. The good kind of bacteria are really very much helpful to the plants.