Dampening off is one of the most common problem when starting seeds. It is caused by a fungus and develops when temps are above 68°F, because—typically—soil is too wet or over fertilized or seedlings are crowded. We are not familiar with the cinnamon cure—trick; it does not sound like it cured the condition. Professionals grow from seed (they sell potted seedlings!) but they may have worked out all the bugs. You might, next time, if there is a next time, use a grow light to get the seedlings started; you do not mention that here. So that once established, the seedlings could be acclimated in/via the greenhouse.
One last thing: So you know that you can direct-seed morning glories? If not, see above for guidance.
Dampening off is one of the most common problem when starting seeds. It is caused by a fungus and develops when temps are above 68°F, because—typically—soil is too wet or over fertilized or seedlings are crowded. We are not familiar with the cinnamon cure—trick; it does not sound like it cured the condition. Professionals grow from seed (they sell potted seedlings!) but they may have worked out all the bugs. You might, next time, if there is a next time, use a grow light to get the seedlings started; you do not mention that here. So that once established, the seedlings could be acclimated in/via the greenhouse.
One last thing: So you know that you can direct-seed morning glories? If not, see above for guidance.
We hope this helps!