Greenhouse and light?

Hi I have flower seedlings growing in a heated dome in my greenhouse. Marigolds, pansies, tagetes, lobelia and alysum.
My problem is the Alysum seedlings are weak, falling over and dying. The Lobelia seem to be on pause. I wonder do I need a light over them even though my greenhouse has daylight from all sides.

 

Hi, my guess is it might be too warm and the atmosphere inside the dome could be very damp.

Alysum as I remember is mostly a hardy annual, so it will not like it warm and humid.
It could be growing leggy or possibly damping off.
My thinking is that you have started this one just a bit too early.

As to lobelia, its always very slow to start, so keep it warm at the roots but ventilate the top so as to allow some air flow, especially during the day.

 

Thank you Pete for replying. Yes they are growing leggy. I wonder Pete when can I safely take seedlings off the heat. My greenhouse read 3.5 oC last night.

 

Thank you Pete for replying. Yes they are growing leggy. I wonder when can I take seedlings off the heat. My greenhouse read 3.5 oC last night.

 

Its difficult at this time of the year, we can all germinate seed at any time , but its the growing on, once germinated that becomes the problem if you sow very early.

Personally I dont sow much until early March, which means once germinated we are then approaching April, a time when the greenhouse is warming up naturally and the light is getting much stronger.
Often very early sowings fail because the growing on conditions are not suitable.

I'd take a chance with the Alysum, if it dies there is time to sow some more, equally with the marigolds and pansies.

Can you not keep the lobelia on a window sill in the house?

 

Yes I think I was a bit quick off the mark with the sowing. Afterall theres still a risk of frost at night. I will have to rethink. Thanks Pete.