Well, my bed started out as part of my strawberry towers idea... When I discontinued that, I had this nice ground cover in place and so decided to see if I could use it to keep out the weeds for gardening some items.
I have very sandy loam here, which is very hard to keep enough moisture - so I put three runs of drip tape down the plastic and anchored it with the same ground staples that I used to hold the ground cover down. Since I wasn't too concerned with fertility of the soil under the cover for the strawberries , all I did was mow it as close as I could and covered it.
It is limited pretty much to planting transplants but could probably work for hills of corn or other seeded crops. You could possibly form beds of compost, manure and organic matter then cover them for more fertility. Since I needed to add fertilizer, I used soluble Peter's fertilizer as I had used in the greenhouse on the tomatoes - through the drip irrigation tapes which I had on a battery operated timer that I found at Ace Hardware for about $20.
Experimentation is going to be in order as I don't want to plant tomatoes and peppers in the same spots - so will try rotating what I plant.
On one section of it, I am going to try the tire stack for potatoes as digging gets to be harder as I get older... I have cut the sidewalls out of some to try it. (Wife doesn't like the idea - thinks it looks too 'redneck'. But if it works, who cares...(grin))
To plant, I have an 1 1/2" auger that I use in my battery powered electric drill - cut an X in the cover and drill to the depth I want to plant. Guess you could fill that hole with potting soil if you wanted, for my tomatoes I just used the soil and watered well.
For me, it was to get away from the weeds! Always seems like something happens every year that keeps me from getting to the garden for a spell and they get ahead of me. (Like when I broke my leg in June of 2007.)
For the tomatoes that I grew on it last year (and peppers) I put a third row down the middle so the 10' became 2' plant 3' plant 3' plant 2' I can just run my mower around it blowing the clippings away from the bed. I had about two tons of tomatoes from the piece of 10 X 100. More than I could use, so I have a whole lot of neighbors who are asking for them again this year.
That cover is now 4 years old and not showing any signs of deterioration. The 15' X 100' I used last year for 3 gallon pots for another project - but will plant that this year in vegetables.
Oh, the soil warms up nicely in the spring, and I have not had any problems with the mid-summer heat - that heating might be beneficial for early starts in Maine. Speaking of Maine, I finally found the hull-less oats I was looking for from Wood Prairie Farm, 49 Kinney Road, Bridgewater, Maine. Never bought from them before, but their email says they are shipping today. Anxious to try that.