Hey there, man I know that really sucks. 😢I seen your question, and thought I'd share this little experience I had with you. First, imo, the previous answers you've received are spot on. Those guys are a lot more experienced than I am. However, I recently had the same thing happen to me. 4 Bruce Banner autos, 3 did well in seedling stage. 1 damped off, and died for unknown reasons. I reached out to some of my associates, and was informed that it had damped off. What they told me was that it could've been for many reasons, such as fungi in the soil, maybe old soil in the pot? Might have been old seeds, cold,wet soil with bad drainage, a combination of some of these, or even, all of the above. I know this doesn't do anything for the loss, but hopefully it'll give you some ideas to prevent it from happening again. I'm growing Do si dos right now myself, but I've had to keep them inside under the lights due to cold weather. I'm not sure, but 50 degrees may have been more of a shock to the Do si dos than to the Northern Lights. Might want to contact RQS, and see what they can do for you. Hope all this rambling helped.😌 Good luck! The NL looks great!👍✌️