Deer love pansies. If I plant any pansies in my garden, deer find them, eat them all, then move on to check out the rest of the garden. Planting pansies is just asking for trouble. However, there are ways to protect plants from deer; if I really NEEDED to have pansies in the yard I could.
Methods of protecting plants from deer include fencing and other barriers, switching to less-tasty plants for at least the outer zones of the garden, and applying products that have flavors and/or odors that deer don’t like.
Fencing needs to be tall to keep out deer
A University of Vermont article by Dr. Leonard Perry explains that deer are very good jumpers. If you are planning a fence to keep out deer, it should be taller than eight feet high. Ten-feet high would be good. Many kinds of materials can be used. One of the lower-cost options is a polypropylene plastic netting, but the only one I’ve seen that is a full 10-feet high is this one by Tenax. Most others are shorter, around 7 feet high.
Alternative fences, including electric fences that might not be appropriate for home gardens, are described in the North Carolina Wildlife article Fencing to Exclude Deer.
A less expensive, non-electric version of deer fencing is described on the blog of Seed Savers Exchange. This version relies on a very different strategy than all the others I’ve seen. Instead of making sure the deer know where it is, by adding flags or other visible cues, it relies on invisibility to confound the deer into not knowing whether the fence is too high to hop over.
Essentially, it calls for 30 lb. monofilament fishing line, which is strong enough to not break easily but fine enough that deer can’t see it well. The line is strung between tall fence posts, at intervals of about 12-18 inches.
This is what the author says:
Once your fencing is done and a deer comes around in the daytime or the middle of the night, it cannot see the clear 30-lb. test line. When they brush up against it, they can feel it and know the something is there, yet they can’t see it. The deer have no idea how high they need to jump to get over the obstacle they have just walked into and they will stay away from the area.
An Inexpensive but effective Deer Fence, by Pat Haberman, SSE member, March 15, 2016
The local Plant-A-Row-for-the-Hungry (PAR) garden is in the middle of a large fenced area. The fence is tall (8 feet, I think) and has kept out the deer. One day last week, though, deer found a gap in the fence. Luckily, Ed, who owns the property, found and repaired the gap quickly. Damage to the garden could have been worse. The incident provided a reminder that we gardeners need to check the fence more often.
Other barriers to protect crops from deer
A local church has built PVC frames to fit its garden beds. The low frames are covered with wire fencing, even across the top of each frame. Deer cannot reach through the wire to eat the plants.
The individual covers for each bed may be inconvenient to store when not in use, but they work, and they are less inexpensive than an entire fence.
In some home gardens, tulle or other row-cover fabric supported by a frame is enough to protect plants from deer. The trick is to cover the plants before the deer find them.
Deer prefer some crops over others
When deer broke through the PAR fence and snacked their way across our garden, there was an obvious pattern to the snacking.
The deer definitely preferred spinach family plants (beets, Swiss chard) over cabbage family plants. Carrots were, apparently, another favored food of deer.
Deer ate the green tops of the carrots. 
Deer ate the tops of all the beets and the Swiss chard plants.
The good news is that the edible roots of beets and carrots were undamaged. We were able to harvest some of each to take to the pantry.
Deer did not eat any of the kale, lettuces, collard greens, daikon radishes, and broccoli. Anyone having trouble with deer browsing in the garden might want to keep these less-favored crops in mind as crops to try next season.
For ornamental plants, University of Georgia Extension offers a list of plants that deer like less well than others. The list is in this publication: Deer Tolerant Ornamental Plants.
Use less-tasty plants to protect deer favorites
The Clemson Extension article Protecting your plants from deer suggests that homeowners try planting in Zones. Author James Hodges describes the method this way:
The zoning method consists of three areas within a landscape. Close to the outside of your property where deer have quick access, use seldom damaged plants. Moving to the middle of the property, you can include some favorites that are rated occasionally damaged. Near the house, plant deer most damaged plants that are your favorites and use repellants starting at planting and regularly during the season to discourage deer damage.
Protecting your plants from deer, by James Hodges, Clemson University Extension, Feb. 18, 2016
You can use UGA’s list of deer-tolerant ornamental plants to use the zoning method in your yard, to help keep deer away from your crops.
Do deer repellents work?
Some deer repellents work better than others. NCSU’s article on Management strategies to minimize deer damage in the landscape tells that human hair and rotting eggs have not been effective at keeping deer away.
The article does include a recipe for a pepper spray that sort-of works:
Pepper Spray: A formulation of 1 to 2 tablespoons of Tabasco sauce in 1 gallon of water sprayed on plants has been shown to have limited effectiveness. Be sure to test a leaf with the spray prior to spraying the plant.
Management strategies to minimize deer damage in the landscape, by Dr. Lucy Bradley, NCSU Horticulture Specialist, 2016.
Use of mothballs is discouraged (in NC, the tactic is illegal), but soap is on the list of things that work to keep deer away. One bar of fragrant soap (brand not specified) protects one square yard of garden, which is not a huge space. Gardeners relying on soap as a repellent may need to invest in a large carton of bars.
For purchased repellents, Alabama Extension offers a comparison of products — by active ingredients, cost, which plants can be treated with each product, frequency of re-application for best effectiveness, and more. The comparison is in the publication An overview and cost analysis of deer repellents for homeowners and landowners.
The publication explains that some repellents work by having a bitter taste, and others work by having an awful smell or appearance. Repellents need to be applied before deer find the plants and learn that the plants are good to eat. Each product has its own schedule for re-applying it. For best effectiveness, follow the instructions on your product.
One of my gardening friends uses the repellent product Plantskydd , which is organic-approved, to keep deer from demolishing her crops. She lives in a neighborhood that has numerous resident deer, but it is unlikely that the HOA would approve the kind of fence needed to keep them out of her garden.
Without the Plantskydd, her gardening would be much more limited, and her harvests of some crops would be non-existent. If you are in a similar neighborhood-situation, repellents may be your best option for protecting plants from deer.