what size pots

Hi All
      I now have a greenhouse and want to try to grow peppers, I have some really
        big pots, but can they be to big?, same thing with melons that I want to have a go at.
         So is there a correct sized pot or what. Any advice would be gratefully recieved.

I suppose they could be too big in the sense that you would have to pay for the compost in the pots, and excess would not be used.

The other issue is over watering, most particularly when the plants are small.  A small plant put into a large pot, and then watered well, finds itself with a lot of water around the roots, which excludes oxygen.  That same plant in a smaller pot can drink enough of the water to let oxygen back into the soil structure.

If you pot on your plants, through pot sizes 9cm, 1L, 2L, 5L and then 12" or whatever final size you choose I reckon they will be fine, and not suffer from precision (or lack there of!) of watering.

Only other issue that occurs to me is how close together you can put the pots.  If the pots are huge you won't be able to get them close enough together for normal plant spacing, so you will have fewer plants - or you can, at that point, plant two, or more, plants in each container.

This is a good little clip on youtube 

URPPQi903ZY
Bear in mind the variety of pepper you are growing. You won't want a giant pot for a tiny variety 

Yep, so have I. No good sowing seeds in cold compost