"do I mulch to cover the ground between plants to retain moisture and replenish the soil gradually or, what I really want, plant beneficial (and hopefully edible) plants in the clear spots between by set plants that will spread out and cover the ground and create a natural ground cover. "

You do both! Mulching is great, as well as interplanting, maximizing your yield for your space. It's really not difficult at all, any space you have open, stick a smaller growing plant in, if the plant is two big you wil have a jungle an look like a miss - For example, if you have tomatoes spacing 4' and you say oh well I got a foot or so in-between the tomatoes, I'll stick a pepper plant in.. Eventually the peppers plant will compete with the tomatoes and sprawl all over like a jungle.. Now if you plant carrots,beets, leafy greens inbetween the tomatoes, you will have a nice low growing edible goudcover that will never get tall and look like a miss.. It will look neat and clean.. You could do this with anything.. The eggplant in the right hand corner bed you could interplant smaller plants, the tomatoes as well, and even the peppers.. Now the cucumbers and zukes are going to sprawl all over and create a groundcover naturally, you don't have to interplant vines like that.. But the tomatoes,eggplant, and peppers, you could diffenently squeeze some low growing plants that will make a nice, neat looking edible groundcover..

Other options are low growing culinary herbs if you use them and or low growing flowers - not edible although some are like nasturtiums - but attractive.

The only issue with using a perennial ground cover is that next year you'll want to moving your food plants around some but as long as you don't mind pulling out perennials - sedum is a good one - then it is much of an issue.

But since you have seen what you want at a nursery then why not ask them for recommendations on what to use?

My personal favorite ground covers are hairy vetch and crimson clover but I don't know off hand how well they would work in your zone. And the primary benefits from them, other than appearance, comes from tilling them in at the end of the season for the soil improvement benefits.

Dave

Looking at your measurements, I'd say you have already done the maximum amount of crowding that you can get away with. Adding any more interplanting will result in disappointingly small yields for everything. I think the people who are advising you otherwise might have missed the numbers on your chart :).

Give your plants time to grow. You will definitely have no soil showing by midsummer!

I am a big fan of mulch, and say go for it :). Put it on top of your soaker hose, or whatever you water with.

For 24 square feet you have quite a bit planted already. You also need some pathways. As digdirt said crimson clover is good in between plants but at this point it's going to be a challenge to establish because you'll be needing to walk in the pathways at least occasionally.

If you decide to interplant something you'll need something to step on while those plants are getting established such as large pavers or flat cobble rocks.

I still think you could fit in a few root crops or smaller plants.. You know better than any of us how much room between plant you have.. A real life picture of your garden would be helpful.

Joe

Good point from Nila. A 6x4 bed is very small and given what you already have planted in it I doubt you'd have space for anything else. Especially at the tomato end unless you plan to do lots of pruning. One cherry tomato plant, depending on the variety can easily get 4' wide and 8' tall.

Why not stick with a good organic mulch this year until you get a better idea of just how crowded this bed is going to get. Then next season you can decide if there actually is room for anything else.

Dave

THatstat, you might want to go read about Square Foot Gardening. Given what you're trying to accomplish in the given space you'll need some of those techniques.

Here is a link that might be useful: Square Foot Gardening

That's going to a full/crowded bed.

You don't have to worry about interplanting because once those plants get a couple months old you're going to have a "green mess" (not necessarily a bad thing) between the cherry tomato and the squash/zukes.

If it wasn't so late in the season for FL, I would say you could squeeze a few radishes in the "dead space" that you could harvest in 30 days, but it's a bit too late in the season for radishes that would taste good. You can probably do that next year, though...weather permitting.