Dealing with deer

I can't remember if I've asked this somewhere on the forums before, so my apologies for any repetition.

I haven't had a problem with deer until last year. They ate the tops off of all my tomato plants, and then ate any new growth every time the plants tried to rally. It's the only year I didn't plant marigolds, but otherwise, I have no idea what would be different.

I have a 4' fence that backs up too woods, but they will come in on via my neighbor's backyard too. Any humane and inexpensive way to keep them away from my garden? Could I just plant mint all along my fence (I know it spreads).

Keep this in mind.  Deer can jump high.  They don't like to jump far.  They also don't do 'detail' so well.  If confronted by a fence they cant get close to they are reluctant to spring over a high fence.  Likewise if they encounter a high fence with a chaotic landing zone on the other side, they are reluctant to take the risk.  Will they?  Can they?  Yes, of course.  Deer are very capable.  The idea is to make the risk higher than the reward.  

Since they don't do detail well, adding things like cd's or shiney foil to fishing line above your fence makes them reluctant, since they see the movement but not the support.  Again, trying to disincentivise your garden.  A double fence or visual barrier on one side or the other gives them pause.  Try stringing a line of from supports in their landing zone with things that will move in the wind or 'bounce' around.  It will likely make them think twice before jumping into something they can't really make sense of.  They are prey animals.  Getting hurt in the wild usually means risking fatality.  Use their nature against thier drive for an easy meal.

Short of 8 ft fencing with unappetizing plants on the outside, nothing I've ever read comes with a guarantee!

Yes, Marigolds have an odour that is supposed to deter pests (deer count as pests in my book), but trust me, if they get desperate, they may decide to eat it anyway.

The same is true of both sunflowers and allium family plants like garlic and walking onion.

Some mints might discourage them more than others.  They do seem to avoid Lemon Balm with is in the mint family. It mows nicely too, in my ecosystem.

They supposedly don't like the furry leaves of comfrey, until we had a dry spell and they were feeling desperate.

If you know a few people with male dogs that need brushing or pruning, I have used dog fur twist-tied to fences at nose height. It has to be refreshed in the spring and every couple of months during gardening season, but it seems to suggest to the deer to go elsewhere. It looks like I've decorated with pom-poms! In the spring, the nesting birds steal some of it, but I'm willing to share. Just having anyone with a dog inviting it over to mark your land regularly, may be of some help.

Some people plant "deer gardens" far away from their "people garden" in the hopes that they will go there instead, but if the population is high enough, and the lack of alternative food sources great enough, this too may fail. I feel a little as if feeding *any* wildlife is a double edged sword, as their population may increase as a result and then the problem just gets bigger.

Here are some threads about fencing. I personally have had no luck with the black plastic deer fencing once it gets a bit old and they get used to it. Nor did I have luck trying to use electric fencing - they just evaded it - I would have had to keep plants too trimmed back.
https://permies.com/t/140079/Wavy-Deer-Fence
https://permies.com/t/154835/Deer-fencing-advice
https://permies.com/t/141026/Dealing-deer
https://permies.com/t/184425/Deer-fencing-sounds-works

I have heard good things about the motion activated sprinklers... between the noise and the water it tends to scare away quite a few different animals.

If you can’t beat them… feed them! 😀

Almost everyone feeds the deer on this island, but two low fences deter deer better than one tall one. They can’t jump and land over two fences.