Thank you for your comments! Since posting this I have discovered the source of the damage. lisaSFbay9b- i was using a diluted 70% rubbing alcohol at the time i first started to notice the damage- from the online research i did I was convinced it was either chemical burn or edema from overwatering. This may indeed have been the case for a few of them; after i completely stopped watering or spraying a few did indeed start to improve (on their new growth). But after scouring and scouring the interwebs I got a tip that turned out to be true: THRIPS!!!!! These nasty, DEVASTATING invaders, previously feared primarily by farmers are becoming a more and more common problem amongst home gardeners. Because it took me so long to diagnose the problem literally every plant on my property, inside and out, is infested. I am slowly trying to eradicate the little devils but have considered burning my house down and starting over more than i would like to admit. I have a little video of one, not sure if i can post, I’ll try to steal a good still from it if I can’t. If you or someone you love might be suffering a thrips invasions quarantine everything and contact your local nursery for spray and root drench options!

I don't know if this helps you or not...but, one thing i've come to learn from living all over California and having grown may succulents of all types for many years is that you must learn which micro-climate you're growing in. California is huge so knowing this is key to success in my observation. In the La Jolla area we get a maritime layer which some of my plants thrive in while others do not. We are at the mercy of what they call "May Gray," and "June Gloom." Find ways to anticipate this and protect your plants as best as you can. Now that we are over "the drought" i have to safe-guard my plants from the deluge of rain we now get in our winter-time. Knowing this now i make sure my soil is quick-draining and in a grittier mix. If your plants appear the same day after day, week after week etc., make sure they're not in a state of dormancy. Aeoniums for example are summer-dormant so i do not water them. They flourish again in cooler temperatures. If you're really having an issue choose a plant and remove it from its pot and thoroughly inspect the roots. Make sure the root system is healthy and insect-free. Many plants stop growing when attacked by insects. Many plants also seem to enter a sort of "stasis" when too hot or too cold. My echeverias for example have curled into a ball due to the excessive heat. This is the way the plant protects itself. They will "bounce" back when the temps cool off a bit. Compare the growing conditions you currently have your plants in to the native environments they come from and adjust as best you can. Absorbing all this will find you one day with all the skill you need to grow your plants successfully. You will know exactly what to do and when to do it. Time and patience will soon pay off. There are many forum members here so full of knowledge and a wealth of experience i am still amazed by it. I still also show up here to learn more from them. --All the best : )

Normal potting mix for a succulent generally retains too much moisture, and 50% coarse sand helps but probably does not tip the balance. If you do not want to hassle with creating your own mix from scratch, I would change the soil to 50% commercial "cactus mix" and 50% perlite. I prefer pumice to perlite since it is heavier and does not float. Since you have your own greenhouse, I am wondering do you have a lot of succulents, and are most of those in the same soil and thriving? Is there any chance the greenhouse becomes extremely humid or hot?

Since flowering rosette dies after, I usually remove whole dying rosette with dried-up stalk. Personally, I would not try to grow them from seeds since they multiply much easier and faster from offsets. Here are some offsets I potted up last fall: Two pots above (there were 4 all together) are those offsets about 2mo later. ...and same pots recently (they were dormant during winter): I am not sure how long you would have to wait for them to grow to this size from seeds, but most likely longer...