I am also planning a garden at my summer place in mid-coast Maine, but need to first do a lot of prep to make a garden area, so I am starting small this year just so I can learn.

I just transplanted some tomatoes plants to 2 ft containers at my summer place. I am only there on weekends.

There are a lot of deer there.

The tubs are in about a 5 or 6 feet square shaped area.

Since it is such a small area for this year, I am thinking of just a 4 foot or so high fence wire mesh fence around them.

How sturdy does it need to be - do they push fences in or out of the way, or do they just jump them? I don't want to electrify it.

I know they can jump 9 foot fences, but would they do that into a very small confined area. Once in, can they jump out from a stand still, or would they just thrash around and ruin everything inside the fence? Will they jump into such a small space? That is, do they see both the near fence and the one just 6 or 7 feet way? Once they are in, with most of the interior taken up by tubs that are 2 feet in diameter, can they jump out without a running start? Do I need to put a wire mesh "roof" over it, and if I did would they realize it or just jump into it and get caught in it and thrash around and destroy everything?

Maybe I could plant some poisoned punji stakes for them to jump onto? (just kidding)

You might want to reconsider electric, since it requires only a single string of electrified wire a couple feet off the ground, and is portable. That's what I use to keep the deer (and our pony) out of my flower beds. On the other hand, my flowers (sitting in the middle of several acres of clover) may not be as tempting as your tomato plants.