The Dreaded Qucik Wilt

Within hours a very healthy lush green month old plant wilts drastically. Within two to three days yellowing and burnt leaves from the bottom working to top. By day three the plant is looking very bad. Nothing new or changed recently in the grow. Other plants just fine. I have scoured the internet only to find so many different opinions. Many people speak of this condition yet nobody seems to have a handle on it. What causes it? What corrects it? Seems to common to not have it pinned down. In my case it is not nute burn for sure. I repeat, a perfectly healthy plant looks like hell in three days. Not looking for your guess. Looking for knowledge please. Any received would be appreciated. Thanks!!

Need pictures, growing method, lights, temps, humidity, and any other relevant information to diagnose problems.

Soil medium canadian spagnum, perlite, worm castings, epsom salts, lime in appropriate proportion in 1 gal containers
Light T5 8 bulb 4' (6500) bulbs 24/7 in Veg
soil ph 6.9
Watered with distilled water every 2 days when top 2 inches of soil dry
temp 80 to 86 under light
humidity approx 60 to 80 % depending on ac on or off
Picture Location
http://i41.tinypic.com/311o1ax.jpg
Plant will wilt while lush green within two days leafs lighter green and brown burnt

Looks like a combination of possibilities

1) soil looks very compact and not drying out all the way(does the pot "feel" heavy?)
2) are you using any nutrients? Your soil seems like a good mixture, but if it sucked all the nutrients out already shits gonna die without some..

what is the PH of the soil itself, and what is the PH of the runoff? What is the PPM of the runoff?

It honestly looks like salt buildup/lockout either due to the soil being too compact/not enough drainage, again how heavy are those pots before you water?

Sounds like you may be over watering. most plants are good to go water wise ever 4 days or so since most soils these days retain moisture quite well. Over watering leads to root rot which can kill a plant in a matter of days and like the above poster said cause salt build ups which cause nutrient lock out and you baby starves.

I appreciate your time massah. Thanks. soil ph is 6.9. I have not tested runoff. The pot of the wilted plants do seem heavier however I take great pains in treating all plants with the same amounts of water. I have used a worm casting tea at 3 weeks old. Have yet to put any serious nute in the mix because I have been so lush and dark green. Thinking seabird guano soon but until this is figured out I hesitate in that. I want to remain organic if possible. Before I water, the pots are light and soil dry to first knuckle. I know about lockout due to over watering but believe that would happen to all 20 not just 2 or 3 subjects. This has taken a lush 6 " plant to yellow and burnt (all accept the top) in 3 days. Amazed how it turned so quickly. The picture link is not my plant. Just a pic of similar wilt. When I skip a watering seems to get worse. If I water as normal seems to worsen as well. Just looking for a treatment that save the plants. Thanks Again!

Rot usually will do that..

Thanks tebin. Have been considering and watching the water issue yet it still is happening. The 1st two inches of soil are almost dusty when I do water. Almost afraid to let them go longer. Feel I have burnt a couple already due to lack of water. Have to find the sweet spot I guess.

If it's only a month old, and you have it a one gallon pot, might I suggest a transplant into a bigger pot with fresh soil. This may or may not solve the current problem, but if everything else is dialed in, as it seems to be by your info, it surely can't hurt things any more than they are now.

Are your plants root bound at all. I recently had the same problem. It seems after a foliar spray they were healed then the next day the same thing, wilted and yellowing from the bottom up.
I would try to re pot them if rootbound could be a possibility for you. also the temps and humidity are a tad bit high(not sure if that is playing a factor)