Which vegetables can be planted this month?

Hi, I'm new to growing vegetables & need a little help. I've got a good
sized veggie patch, with raised drills containing farmyard manure & a
top layer of compost. Last weekend I planted carrots and lettuce which
my dad assured me would be fine at this time of year. I have seeds for
cucumber, corgettes, corn, beetroot, red onion (bulbs), pumpkins etc.
I'd also like to grow cherry tomatoes but I'm at a complete loss as to
how to start them successfully.

Also, I would like to grow a few blackberries & rasberries but I'm not
sure of the best place to purchase the plants. I saw plants in a local
'Instore' the instructions said the roots should be soaked in water for
an hour before planting, but would these particular plants be of enough
quality & would I see any fruit this year? 

I live in Northern Ireland, so I don't want to plant anything too early
and risk any unwelcome weather. However, most people I've spoken too
think April is the right time to plant most things.

Sorry to sound so clueless, I'm just a student who wants to make use of
the land I have at home & hopefully get some delicious vegetables some
time in the future!

Thanks.




-- 
Freedom_Spark