Do Pea's crop more than once, if not can you re-use the grow bag after Pea's have finished

They may still produce a few flowers and therefore pea pods, but if you want to re use it then the best veg are one that require high nitrogen. Peas 'fix' nitrogen into the soil by there roots. The tiny nodules on the roots.
Brassicas usually follow legume crops because they need the nitrogen to be grow into big healthy green plants. Its probably best when peas have finished to chop them off, break up the soil and roots and try brassicas. Ive never grown B in grow bags so i cant say how well they will do