On 28/05/2013 10:36, Jilly wrote:
I have my tomatoes in 3inch pots in green house - plants about six inches high
- good growth.
When should I transplant to ten inch pots in greenhouse?

I'd re pot them into 6 inch pots now, then when they are about 12
inches, with the first truss of flower showing then pot them into your
10 inch pots.
Keep them well spaced to stop them going leggy.