[lacewing]

My tomato plants are turning blue, the underside of  the leaves are a purpley blue colour.
They are in  heated greenhouse where the temp. is kept at around 60 to 65f. I seem to remember reading somewhere that toms. turn blue when cold, but surely mine should be warm enough at the above temp.?

[gillie]

Yes, they are too cold!  It will not harm them very much, but try to put them in a slightly warmer place.

Gillie

[mumofstig]

I agree with gillie, 60 is the absolute lowest they can stand, so turn the stat up a little bit if you can

[lacewing]

Will do,  thank you!

[Rangerkris]

Mine are blue then, but will have to do 

[mumofstig]

Kris, can't you fleece them for a while?, it makes all the difference to them

[UrbanG]

Aharrr, All becomes clear now then 

All my Toms on my indoors window sills are fine and look great, while the ones that are in my cold house have purple / bluey stems!!  So I guess its still to cold for them in the cold house.

I have fully ran out of room on the window sills though, to the point where the clocks and ornimants have all had to be relegated to the cupboards for a while

So I guess like Chris, I shall have to just leave them and wait and see 

[mumofstig]

when I finally leave my toms out they will be under a poly tent or fleece at night until things really start to warm up.
Some people use one of those little cheapo plastic polyhouses inside their greenhouse for the added protection at night 

It is still much too cold for them really, although it can be lovely and warm during the day, nights can still be frosty (although it is usually gone by the time we get up!)

[Rangerkris]

I can do better than that i can bring them in the house, i will get on to it in a few min's.

[Rangerkris]

Have just moved 10 plants inside to the house will try and fleece the rest this evening.

[Rangerkris]

Wow what i difference a few days makes with the tom's being inside the house, they are much bigger than some i left in the greenhouse.  Thanks All for the advice.

[Kristen]

I agree with gillie, 60 is the absolute lowest they can stand, so turn the stat up a little bit if you can

Hmmm ... I always thought that 10C was the lowest Toms were happy with? That would be 50F I think (and 60F would be 15.5C and even I would be reasonably happy sleeping in that with a nice duvet!)

Is the heater's thermostat working? or perhaps it could not output enough heat for some nights' temperatures?