Yes is is easy to grow lettuce and cabbage in raised beds provided you have dug some compost or well rotted manure into the bed.

Tip.
ref to many lettuce at one time;

If you find you've planted to many lettuce at any one time and you fear they'll bolt!!

All you need do is dig the lettuce out of the ground

(making sure you've got a good root ball on each lettuce)

leave the lettuce near the place you've taken them from for about an hour and then re-plant the lettuce back to where you dug it from, And give the lettuce a very good water,

you'll find the lettuce will look limp & sad for a day or so but infact you've slowed down its growing by about a week,

You can only do this once "but" its saving you the lettuce waste ref the table use.

tried & tested many times,

Interesting!

many thanks, i have some bags of dried horse manure , so will mix that into the soil of the raised bed before planting,
i am alSo growing some scented pinks, they are doing well at the moment, in three inch pots, i see the forcasters are mentioning, some frost , so will be watching the forecast carefully, by the way , i have read that the nutrients in
organic veg , are in much greater quantity, nice thought!,,, John

There is more nourishment in organic veg John and you aren't eating artificial pesticides and herbicides!