This has always struck me as odd, since black plastic doesn't absorb a lot more sunlight than dark colored soil. But I guess it adds a layer of insulation, so that to the extent the soil warms up, it won't cool as fast. In that regard, any plastic would do. Clear would probably work as well as black.

Fruit production starts to tail off for tomatoes when nighttime temps don't get much below 75F. Peppers and eggplants should do fine. But that's air temperature. Your plastic on the ground won't affect the air temperature, one way or another.

To the extent you have plants growing on the black plastic, they'll shade it, and you won't get any ground heating at all. I mean, the idea is that once the plants are mature, the sunlight should hit THEM, not the plastic.

I assume this plastic is perforated, so you can irrigate?

You can just check the soil temp, and if it starts getting uncomfortably high, just throw some leaves or newsprint over it.

Eggplants are native to India, where it gets hotter (and stays hotter for much longer periods) than anything your zone 5 climate can dish out. Peppers a little less so, but for both crops, the benefits of plastic mulch outweigh the disadvantages of bare soil.

I have black-plastic mulched few of my beds. I might remove them by July. So it depend how hot it gets in your garden. If day time highs are near 80F or higher and night temps 55F or higher, I would get rid of plastics. Plants root don't need a real hot soil. Maybe eggplant is an exception. Then I grow Japanese eggplants not INDIAN:

Farmers grow acres of veggies under black plastic, and they certainly don't pull it off during the heat of summer. When it does get hot, the plastic serves as a weed barrier and retains water. If you really want to do some extra work, you could always remove the plastic and replace it with organic mulch. I've done so in the past when I only had a single row of tomatoes.

You should be fine using it. I'm south of you near Grand Rapids. A garden I help with has used black plastic to cover beds for several years. Tomatoes, eggplant, squash, cucumbers, melon, etc. all grow fine. It eliminates most of the weeding and keeps soil moist much longer. It's great for a large area that we can only visit once or twice a week. Lots of small holes were drilled (yup, with a power drill) into the plastic roll before laying it over the soil. It lets rain through fine and is easy to water with a hose during dry spells. I've never seen production slow due to overheating of the soil around here and imagine you have similar if not cooler temps up your way. It's not often that air temps here interfere with blossom set either. Sometimes for runner beans, but not the tomatoes, peppers, eggplants, and melons.

FWIW, I've used the black plastic in well drained sandy loam. Not sure if it would work the same in heavy soils.

ANOTHER CONSIDERATION:

once your plants (like tomatoes) grow big they will shade most of the bed. So the plastic is shaded most of the time also. Its advantages under such conditions are:

---- retain moisture (reduce evaporation)
---- prevent rain water to go down(to some extent)

Disadvantage: In hot days, it can get real hot under black plastic. If some roots are growing under it can be cooked. It also prevents air from getting into the soil. Micro organisms and roots can appreciate some air.

So all in all there are trade offs that one has to weigh and decide what to do. I can leave them on since we have relatively cool summers and I get no more than 6 hours of direct sun.

What seysonn says is right, except that if the bed is shaded, it won't get hot under the plastic. The temp in the shade is the air temp. I agree that soil aeration is important, thought if you have enough perforation in the plastic to allow water to get through, that won't be a big issue.