Alrighty guys, a couple days back my leaf tips started curling under. I thought it was just heat, but it has gotten worse. The new growth is bright green, old stuff is real dark. Its apparent to me that its an overdosing of nitrogen. The ph of my input is 6.8-6.9, runoff is 6.7-6.8, so I'm pretty sure it's not a ph thing. Take a look at these pics from today and last night, and let me know what you think. I really don't have the ability to flush all of the plants, as that would require about 63 gallons of water. I suppose if that's all that would cure this problem, I could make a run on all the distilled water at my local grocery stores, but that would be mighty suspicious. Would simply feeding them water and molasses for the next 2 feedings (1 every 5-6 days) be sufficient? Thanks in advance for the input;-) BTW, on day 17 of flowering, and I've been using fox farm big bloom and tiger bloom flowering nutes at about 1/2 strength...

You should be able to flush all of the plants at any time. This would be my first suggestion. Second would be to flush the plants.

I would say that for sure too much nutrients, very dark waxy looking leaves means that you are over killing the fertilizers and possibly causing root burn which is stressing the plants and causing the tips to curl. You need to flush with pure water. It doesn't have to be osmosis water; get a large container and fill with just tap water and let if sit for a day and use it to flush them. (if its city water it also contains chlorine which will change the ph, by letting it sit you are allowing the chlorine to evaporate off and letting the water to become room temperature) You don't have to use osmosis water to water your plants if your using soil based mediums, most fertilizers are actually designed for regular tap water which already has some minerals in the water. For at least the next two weeks don't give them any more fertilizer just give them water. Don't overkill your plants, if you use a good soil mix that has a good amount of compost that will load the soil with nutrients you can end up with very large healthy plants with out using any fertilizers at all. Go easy, start off with less than half of what it recommends for feeding, as you continue vegetative growth you can increase the amount but pay attention to what the leaves look like, they should be a nice green, not too dark and not waxy, new growth will be slightly lighter green in colour. good luck my friend all you can do is flush and cross those fingers and hope they recover!!!

Thanks guys! (OC, were you being sarcastic with both suggestions being the same, or was that just a brain fart?) The leaves aren't really waxy looking to me, and one of the plants new growth has some spots on it that are much lighter than the rest (nute burn obviously) I would really rather not put 9 gallons of tap water through each plant (3 gallon grow bags), as our waters' ph is 8.5 from the tap, with who knows how many nasty chemicals and such in it. Furthermore, my municipality uses chloramines instead of straight chlorine for disinfection, which I understand is much more harmful to the plants. So do you folks think watering with 1-2 gallons per plant should do the trick?

This is a good link that should help you out and in future grows...Peace

http://www.marijuana-seeds.net/Thanks-ThankYou.htm

Sorry, i thought my first suggestion was "make sure you CAN flush the plants" and the second was "FLUSH the plants". 1-2 gallons per plant should be fine.. and your chlorinated water, you can let it sit out for a day and most of the gas is evaporated. Or you can go to home depot and spent 130 bux on a RO kit.

Do what you can but flushing is all that you can do now that the damage is done. You gotta try and flush as much of the excess nutrients out of the soil as possible. That's why its always better to give your plants less fertilizers and see they need more then over killing it cause once its done, its done all you can do is flush with water to flush out the excess nutrients and hope for the best.

and for your water situation if you have that many plants going I suggest investing in a osmosis water system to filter your tap water, It would be a worth while investment instead of buying jugs from the store.

Thanks guys (or gals...whichever). I had been using 1/4 strength nutes, and when the plants showed no adverse effects, I upped it to about half... I guess this was a bad idea lol. This is my second grow, my first one was a good learning experience, but I could have done much better (I was using hydro nutes in soil plants up until about week 3 of flowering... guess I should have realized hydro nutes are different than soil nutes). This time around I've invested in a high quality bluetech labs ph/ppm pen, upgraded the ventilation somewhat, and am using quality seeds instead of bagseed. I have done some reading on 70 gallon/day RO systems, but still have a few basic questions. Do I set these up in-line to my sink, and do I need to store the water after it has been filtered, or does the filtration happen real-time when I open the faucet? These are admittedly stupid and basic questions, but I cant seem to find an answer...
<edit> Buddha- Thanks for the info. I'm not trying to be a dick here (although I know I seem like one, I just cant figure any other way to say it) but I've looked at that guide a few times (It's also posted in the faqs/troubleshooting etc sticky in new growers primer, under "an answer for every question" or something along those lines.) What wasn't provided however was a way to judge the severity of the problem, which is what I was wondering about. The only reason I added this edit was that I didn't want people to think I was asking stupid questions that I hadn't done some research on my own about. I have noticed since I've been back that there has been an unusually high number of "lazy" questions posted here, and I wanted to clarify that I'm not one of those posters lol. Once again, not trying to offend you Buddha, just wanted to make sure there was a common understanding! Thanks for the contribution either way!

its all good there is no such thing as a stupid question. If you don't ask questions you never learn, its better to ask and gain more information that is gonna help you in the long run.

anyways about your osmosis question... I have an osmosis system for my drinking water, I don't use it for my plants. I have very bad well water that is loaded with extreme amounts of iron so I have a chlorine injection system with a series of filters that removes the iron, so for my babies I just take the water after its gone through the chlorine system and the ph is all balanced and such and I let it sit in a container for a few days so the chlorine evaporates off and Its fine for my babies.

The way my osmosis system works is after the water goes through the chlorine injection system and series of filters it goes into a large holding tank for all my homes water, a line comes from the tank to the osmosis system and water softener which is another series of tanks and then goes into a holding tank that you can get in different sizes. A line is fed from this osmosis holding tank to a small tap in the kitchen that is beside the main water tap.