"Mike" wrote in message
...
Hello,

Planted some "Tomato Tumbler" plug plants last week each one in a large
pot using stuff from a grow bag and some water crystals.

Noticed today that the young plants are going a bit yellow.

Is this too much sun, as they are out all day or nothing to cause concern
?

Yellowing is not good.

AFAIK you can't give tomatoes too much sun (certainly not in the UK).

Could be too much water - ISTR that cold/draughts can turn the plant
purplish but not yellow.

Is there reasonable drainage?

Once established and growing strongly it is hard to overwater tomatoes (but
it can be done if you try really hard), but when they are little they need
more care.

HTH
Dave R