but am thinking they need to move their nest elsewhere.

Why? Do you pollinate by hand?

Dan

Dan - No, but I have a young child who plays near the garden, and they are preventing me from working in my garden as well.

If they are Yellow Jackets, it can be a safety issue as they can be aggressive defending their nest. I had a similar problem a couple of years ago. I couldn't go anywhere near the raised bed, so I had to use chemicals. The raised bed was built with old RR ties and they were deep in the rotted areas. If you can see where the entrance is(there may be more than one), get a can of pesticide that shoots a long stream, go out at dusk(or later)when they're not active, stay a safe distance away and shoot as much into the hole as you can, then retreat quickly. Dress covered from head to toe just in case. It may take a few days for the nest to die, but over time you will see less and less activity around the entrance.
I know it sucks to have to do this, but you and yours need to be safe in your garden. I accidentally stepped on a Yellow Jacket nest once, and a swarm of them chased me for a block, and yes, I got stung. Whatever you decide to do, be safe! If need be call in pest control to take care of it for you.
You can also check out the pests forum for threads on bees/hornets/wasp nests. HTH

Here is a link that might be useful: garden clinic

I've never had a problem with bees, we always have something in bloom between frosts, and we've taught the 6 y.o. how to play around bees when she sees one. Unless one is allergic, there shouldn't...erm...bee...a problem with them - it is not in their interest to die when stinging something, and e.g. bumblebees with small colonies avoid this at all costs. YMMV.

Dan

I understand what you're saying Dan, and I like seeing honeybees, bumblebees, even wasps in the garden. I've even put up houses for carpenter bees. They are all beneficial and most of them are pretty docile unless accidentally handled or caught in clothing. But Yellow Jackets(and some others)can be wicked aggressive while defending their nest. To me, this is what it sounds like the OP has. Maybe the professionals could be called in to get a positive identification on the nesters before a decision is made to exterminate, but if something is aggressive enough to keep me out of the garden, it has to go. That's just me.

Yes - I could be relying on an assumption of a correct identification, but I am...ahem...bee-ing explicit about bees. I have not mentioned yellowjackets. But I agree we should ensure of the species and go from there.

Dan

Identify the entrance to the nest. Set a shop vac on suction and position the nozzle near the nest entrance. As the bees attempt to enter or leave the nest they will be sucked up and killed. After a day or two the nest will no longer be viable and your problem will be solved. Remember . . . . nothing can live in a vacuum.

I have the same problem with yellow jackets(I think) under my bed. I got stung recently and a sting never hurt that bad and for 4/5 hrs.. A friends used this method, and it worked. I think this is a genius idea and will try it. Thank you