compost too strong/rich possibility??

Hi,
I have set up a raised bed using a compost made from 40% food waste, 40% green, 20% fish waste and another raised bed using really well rotted manure. Ive some veg planted, rocket, broccoli, cabbage. The veg in the manure bed seem to be doing nicely but in the other bed growth is slower but leaves much greener in colour.
i suspect that the bed with the fish waste compost is very high nitrogen content and maybe too strong for the veg and thus producing the darker leaves at slower rate.
i appreciate anyones views or ideas about this?
would a mulch of wood chips help?
thanks
Aidan