50% dead leaves! Bad!

[anongreen]

So, this has been a slightly ongoing problem. Slowly, the leaves on my plants, from the bottom up, have been dying. The ph is good...but I have poor ventilation. I'm thinking that either light coverage isn't penetrating to the bottom, or it's getting too hot. It's pretty bad right now!
Here's what they looked like on May 5th:

And here is what they look like now:

[Toka-Cola]

how do ur roots look like? if its got that "woody" smell to it, its rotting...

[anongreen]

My roots look clean. Same color as they've always been, and same smell, although they're very tangled because of the small container.

[Swa_Swa]

need more info...post up your ph and your feed schedule along with all that other great stuff. Looks like nitrogen and magnesium deficiency to me.

[anongreen]

I've got them on two 105 watt CFLs 2700k, and a smaller 30 watt one for the lower parts. I'm doing the Lucas Formula with General Hydroponics and I flush out and replace the nutrient solution every two weeks. The amount of water in the container is about 2.25 gallons. Since they drink a lot, I add fresh water to the mix every couple of days. I try to keep the ph between 5.5 and 6.0, but sometimes when I check it peaks to 7.0.
If it's a deficiency, should I just up the nutes, or are there compounds with whatever mineral that I can add?
I planned on flowering them about now, but now I think I have to wait until they get healthier...I've been thinking about putting them on the flowering schedule for nutes, if it is the case that they're suffering from some deficiencies..

[Help_Needed]

Originally Posted by anongreen

I'm doing the Lucas Formula with General Hydroponics and I flush out and replace the nutrient solution every two weeks. The amount of water in the container is about 2.25 gallons. Since they drink a lot, I add fresh water to the mix every couple of days. I try to keep the ph between 5.5 and 6.0, but sometimes when I check it peaks to 7.0.

Here's your problem. If your using the top-off and replace version of the Lucas Formula you should be refilling your reservoir every time you've added enough water to equal the volume of your reservoir. Since your reservoir is only 2.25 gallons, and you've got so many plants in there, you're probably hitting that number in just a few days.

What I'd recommend is, every time you change the water in your reservoir, fill a container with 2.25 gallons of plain water, and use that for watering your plants. When the container is empty, it's time to change our your reservoir.

When your pH hits 7.0, it means that almost all of the nutes have been eaten by your plants.

Also, 6 plants in a 2.25 gallon res is WAY too many. In a DWC system you really need 3 gallons per plant, minimum. You might want to get rid of some plants or move to a larger system.