They appear to be small enough to still successfully transplant but it will take some care as the roots of the two are likely well-mingled by now. And it will be a system shock to both but they should recover.

I'd just carefully dig by hand between the two plants and try to get as much of the rootball as possible of the one to be moved.

5 gallons per 1 pepper plant is the common recommendation for best success despite what the nursery said. I have done two in one 5 gallon pot in the past but the production and overall health was very reduced. They can be done in less but require much more attention to nutrient levels and watering.

And it also depends on the type/variety. Not all pepper plants are the same size by any means. Hot varieties tend to be much smaller than sweets for example.

Dave

I agree with Dave up there. A 3 gallon container is a good start for any variety of pepper, except the "dwarfiest" of them, with 5 gallon being better on average. I like plain old buckets as they are cheap and the depth makes for less water retention in the root zone, even with sufficient drainage holes. Look up "perched water table" in the following link.

http://forums2.gardenweb.com/discussions/1375349/container-soils-water-movement-and-retention-xviii

That being said, I transplanted 3 Biquinho Amarella peppers in a single 3 gallon container, because they grow so slow and just to see what happens.

it sounds like the employee works for a paycheck and not to disseminate useful information ...

@bragu_DSM,

I'm not certain who this comment is directed towards, but in any case, it is the least helpful to the OP yet.

Thank you all for your help!!!

i have moved the plants to 5.5 gallon containers and hopefully they will live!