They die when I put them to bloom

white widow offshoots seem to do this. (I have one now that lost all its fan leaf sets like that for no reason I can detect, only buds and sugar leaf left. same soil, light and feed to other plants and they are deep green and flourishing, all are healthy)
 
 
you can try some of the tips in the growers section though.

 

how long are you letting them veg for? I believe that most auto flower strains still take up to about 4 to 6 full weeks of veg before they are ready to switch to flower, also with auto flower's you may want to go down gradually with the light schedule, like 18/6 for first two weeks of veg, 16/8 the next two, 14/10 the next, and then to a 12/12 may help.  Umm also what are you fertilizing with? Be careful not to over do it, also make sure to flush at least once a week with  some type of flushing agent so you don't get nute lock up.

 

Always flush your plant and then give them superthrive through the transition period (first 5-7 days of flower) and make sure the PPM of your nute mix is not too high or even too low.
 
You might be killing them with something you are giving them...possibly you have really jacked up humidity or temperature?? Who knows your plants could also be diseased

 

if youre using veg base nutients than your plant is probably high in N in veg. when you switch to flowe the plant which i used to getting all the N in veg is not getting what it is used to so they start showing signs of N deficiency and start turning yellow...you just need to feed them some nutes that have some N in them to easy it out of the veg stage pretty much so it can go into the flower stage healthy...btw at the end of flower you want as little N as possible therefore the flushing process is needed to strip the plant of any left over nute build up and then youre leaves should turn yellow indacating that your plant is pretty much ready for a clean harvest... best of luck !

 

That's not how autoflower works.

Autos flower in any light schedule once they reach a maturity threshold. There is no switching to flower.

 

I know that auto flower starts to flower automatic when they are ready, that is why they call them autoflower duh, but with all cannabis they still need a veg cycle and a flower cycle when it comes to light, not good to keep an auto flower in 18/6 light schedule, when they start to flip over into their flower mode. when you start to see those hairs you need to drop your light schedule to a flower type schedule or it will freak the autoflower out. Also as to greens problem, it could be nute problems, it could be light, could be over or under water, hard to say without pics.

 

You can run autos at 24/0 and they will finish. Most breeders recommend 18/6 or 20/4.http://forum.grasscity.com/index.php?/topic/1269823-This-old-Hippies-Organic-Garden.This old Hippies Organic Garden.

 

Yea even flushing can have a negative effect cause what ever you are trying to fix is being flushed and shit get mixed up but its also good to get everything in check...flush it, ph balance it, and start your nutes at half or maybe less strength. If you have to ive heard of people using veg nutes in flower also if they're having an N deficiency early in flower...some pictures could definitely help us to help you unless you're trying to fight this alone but like I said before best of luck!

 

I have had this same problem recently too. They start to shrivel up and get a very light color, and then droop and die. I was just growing bag seed for the past year to get my feet wet and I got tired of using up all the fertilizer and other nutes on them, because while I was getting decent stuff it wasn't great.
 
My theory is that when the plants switch to 12/12 they have a huge growth spurt, and if there have been no nutes through veg the plant doesn't have what it needs built up to support that growth spurt. That is just a guess but it makes total sense,nd like I said it didn't start happening until I slacked off on the nutes.
 
Now I have switched over to better strains and I am making sure everything is exactly on point from the soil (re-amended all my base soil) to the nute schedule. I was doing that in the beginning with the bag seed and had no issues whatsoever. The nutes really do matter, I thought I could get by without them.
 
I will post a few pictures of some I have in flower right now that are struggling along but had no problems at all in veg. It is a bunch of them.

 

Auto flowers are not photoperiod so they effectively see no difference in 12/12, 18/6, 20/4, 24/0. You do not need to do anything to an autoflower other than tend to it. The lights never have to change, they grow out just fine regardless. Maybe in the early days of autos before the breeding was stabilized and refined, but current autos are stable enough that they'll do well in any light schedule.

 

Some plants are sensitive to nutrients. It might also be the coco. Some plants like to be grown in soil. You should try to flush your plants then give em bloom nutrients but a lower dose

 

your right back when auto flowers first started to get popular they were still sensitive to light and we needed to mimic somewhat of a winter schedule for the later part of the flower to increase yeild.  Stopped using them, didn't care for their yield. So your right they may be better now.

 

That could be it right there. Those first couple weeks of flower when they use up all that N and stretch out they need the medium to allow for root expansion. If it's packed super tight than the roots are not getting sufficient oxygenation and room to grow. The devil lies in the details.

 

when you first go into flower, keep them on veg nutes for a week or two. That should help with any early flower Nitrogen deficiencies....it also helps with the whole stressing issue you can run into going from 18 hours of light a day to 12. The auxins and hormones in the plant take a little while before they're fully prepared to take on flowering, for that time continue to use veg nutrients.
 
also I'm surprised nobody has asked the obvious yet: are you keeping track of nutrient concentrations in your feeding? it could be a simple case of over/under feeding when you go into flower.