It is possible to have a nice garden with both plants and turtles in the same space.
Land or box turtles are a lot of fun and if you have a pond, water turtles can be very interesting.
Box Turtles
Box turtles make great garden pets as long as you don't mind them eating a few of your plants. Every morning, we feed ours moistened bulk fish food. They love cantaloupe and they help themselves to our tomatoes and strawberries. Once a week they recieve a tiny piece of uncooked hamburger meat, which they seem to really appreciate.
We like the turtles, so sharing our harvest with them is really fun! If you don't want to share so much, try fencing off an area just for them, burying the bottom of the fence about a foot, so the turtles don't escape.
Use chainlink fencing or something similar, as they can actually climb chicken-wire. Also, if the holes in the fence are too large they will escape or get stuck trying and possibly die before you notice them.
If you are lucky enough to have a mating pair, and you have provided an area for egg laying, you may have baby turtles and if you do, you will need to add a layer of hardwire cloth to the bottom of your fence, so the little guys don't escape.
Give them a constant supply of fresh water and a moist shady area to burrow down in. Feed them daily and you will have some happy turtles. Ours actually come to greet us when we enter the garden.
Land turtles like to go for an occasional swim, but they don't really swim, their bodies are too heavy and they sink. What I'm saying is that you can have an area of water for them that is deep, like a pond, but they must have a way of climbing out, sloping areas on all sides will work well.
Water Turtles
Water turtles can be very satisfying garden pets, but they are a little more complicated to keep. They may be small when you get them, however they grow quite quickly, so unless your pond is on the large side, I would not recommend a water turtle.
If you do have a large pond, you will also need to fence in the pond, so the turtles don't escape.
Use chainlink fencing or something similar. Also, if the holes in the fence are too large they will escape and die, they are not like the box turtles, they can not live out of the water for very long.
If you are lucky enough to have a mating pair, and you have provided an area for egg laying, you may have baby turtles and if you do, you will need to add a layer of hardwire cloth to the bottom of your fence, so the little guys don't escape and die.
Water turtles can get into your skimmer and get stuck there or end up somewhere they should not be, so you should check on their whereabouts at least once a day.
Feed them daily in the early morning or right after the sun sets. Floating food is best, feed just enough that they finish all of the food either before dark or in 15 to 30 minutes.
Water turtles like greens, so throw in some lettuce or other green leafy plants on a regular basis. You will need to experiment to see what they like.
If your turtles are large, you will have a hard time keeping plants in the pond, water lillies never made it in our pond, the turtles would chomp the stem in half and there goes the whole lilly pad!
You either have turtles or plants, but usually not both, unless your pond is huge and the turtles are few.
Water turtles hibernate during the winter at the bottom of the pond, breathing through special orafices near their tail. You must keep the pond water aerated through the winter or they can't breath and will die before spring.
We have raised turtles for over 40 years and more will be written on both water and land turtles in the garden, breeding, incubating eggs, sexing, helpful hints and more, so check back soon.