Purple tomato seedlings

[bendm]

I'm getting a bit worried about my tomato seedlings and was wondering if anyone can help me out.
They are growing nicely(about 4 inches high)on a windowsill,but lots of them seem to be going purple on the undersides of the leaves.The top of the leaf is fine, and apart from this they seem healthy.What is this and is there a remedy?
Any help appreciated.
Ben

[janeyo]

Mine are purple-ish too. Thought that was normal and they go greener as they get bigger.

Am sure someone will enlighten us!

janeyo

[fiveravens]

It doesn't sound serious, but they might just possibly be getting a tad short of nitrogen. Might they need potting on into slightly larger pots?

[Arachne]

It's generally a low phosperous thing (I'm assured - first year of growing 'em myself). This can apparently be caused by cold soil, and they can grow out of it as the soil warms, or just give 'em some plant food that has phorpherous for them to snack on in. I used Tesco organic plant food on mine, and the purple's gone.

[Mike and Louise]

Our tomatoe plant had purple undersides to the leaves when it was about 4-5" high and it was still in it's small pot on the window sill.

Now that it is in the greenhouse in it's now bigger and permanate pot the leaves are greener.