A little info that sheds more light...
I'm also growing 'Cup and Saucer Vine' (cobaea) which is hardier than Morning Glory. It's classed as H2 (hardy down to between 1 and 5 degrees C) - MG is H1c - (hardy down to 5 and 10 degrees).
We've been getting night time temps of between 8 and 10 recently - with perhaps very brief dips down to 7. So I put my Cup and Saucer vines out to harden. Some of the very small ones with only 2 leaves are looking very unhappy, but the bigger ones are thriving. A little research revealed that young seedlings will be killed off by anything below 10 degrees, and that bigger seedlings will be killed by anything below 7 degrees.
So, whilst Cup and Saucer vine SHOULD be fine down to somewhere between 1 and 5 C, when it's small it needs to be kept much warmer.
Chances are something similar applies to morning glory. Last year I planted mine out when the were still fairly small - probably at a very vulnerable stage. Chances are they need temps closer to 15 degrees at night when they're small. Sowing a bit earlier and being prepared to bring them on indoors until they're quite big might do the trick.
I'm also growing 'Cup and Saucer Vine' (cobaea) which is hardier than Morning Glory. It's classed as H2 (hardy down to between 1 and 5 degrees C) - MG is H1c - (hardy down to 5 and 10 degrees).
We've been getting night time temps of between 8 and 10 recently - with perhaps very brief dips down to 7. So I put my Cup and Saucer vines out to harden. Some of the very small ones with only 2 leaves are looking very unhappy, but the bigger ones are thriving. A little research revealed that young seedlings will be killed off by anything below 10 degrees, and that bigger seedlings will be killed by anything below 7 degrees.
So, whilst Cup and Saucer vine SHOULD be fine down to somewhere between 1 and 5 C, when it's small it needs to be kept much warmer.
Chances are something similar applies to morning glory. Last year I planted mine out when the were still fairly small - probably at a very vulnerable stage. Chances are they need temps closer to 15 degrees at night when they're small. Sowing a bit earlier and being prepared to bring them on indoors until they're quite big might do the trick.