How Fast Do Box Turtles Grow?

Are box turtles bigger or smaller than other kinds of turtles?

What affects the growth rate of box turtles?

Knowing the growth rate of these reptiles can help turtle owners understand the health and well-being of their pets. 

Stunted growth could be a sign of a husbandry issue or medical condition, so it’s important to be able to recognize it. 

This article will discuss growth rates, sizes and lifespans of box turtles, as well as the factors which affect the health of pet turtles.

how fast do box turtles grow

How Fast Do Box Turtles Grow?

The exact growth rate of box turtles depends on the species, sex and condition of the animal, but on average they will grow 1” inch (2.5 cm) per year while they’re young. As they age, their growth rate will slow to around 0.5” inches (1.25 cm) per year until they are full grown. Box turtles reach adulthood, on average, in 7 to 10 years, when their shell fully hardens and they reach full size.

How Large Do Box Turtles Get?

Adult box turtles reach between 4 to 8” inches (20 cm) long. 

There are some subtle differences between species, however:

Species of Box TurtleMaximum Growth (length of carapace)
Eastern box turtle4.5 to 6” inches (15 cm)
Three-toed box turtle4.5 to 6” inches (15 cm)
Ornate box turtle4 to 5” inches (13 cm)
Gulf Coast box turtle5 to 7” inches (18 cm) 

The Gulf Coast species is the largest of the box turtles. 

The three-toed and eastern box turtles share many similarities, including overall size.

How Long Do Box Turtles Live?

Wild box turtles may live anywhere from 25 to 50 years. 

Some wild turtles have even lived longer!

Turtles in captivity tend to live a little shorter, in most instances.

Species of Box TurtleAverage Lifespan
Eastern box turtleMore than 26 years
Three-toed box turtleMore than 26 years
Florida box turtle22 years
Ornate box turtle7 years
Common box turtle30 to 40 years

Lifespan is another similarity between three-toed and eastern box turtles. 

Additionally, ornate box turtles have quite a short lifespan compared to the others, and the common box turtle is expected to live a long life regardless of whether it is wild or captive.

Comparing Growth Rates Across Turtle Species

The following table compares growth rates amongst a few different species of turtles.

Age of TurtleSpecies of TurtleLength of TurtleFurther Details
HatchlingCommon box turtle1” inch (2.5 cm)
Painted turtle0.8” inches (2 cm)
Map turtle1.2” inches (3 cm)Males
Map turtle0.8” inches (2 cm)Females
1 yearCommon box turtle1.4”  inches (3.5 cm)
Painted turtle2” inches (5 cm)
Map turtle1.6” inches (4 cm)Males
Map turtle1.7” inches (4.2 cm)Females 
Red-eared slider1.1 to 1.6” inches (4 cm)
2 yearsCommon box turtle1.8” inches (4.5 cm)
Painted turtle2.7” inches (6.9 cm)
Map turtle2.3” inches (5.8 cm)Males and Females 
Red-eared slider2.3” inches (5.8 cm)
Snapping turtle5 to 6” inches (15.2 cm)
4 to 5 yearsCommon box turtle3” inches (7.6 cm)
Painted turtle3.1” inches (7.9 cm)
Map turtle3” inches (7.6 cm)Males 
Map turtle3.8” inches (10 cm)Females 
Red-eared slider4.5” inches (11.4 cm)
8 to 10 yearsCommon box turtle5 to 6” inches (15.2 cm)Full grown
Painted turtle4.7” inches (12 cm)Full grown
Map turtle4.5” inches (11.4 cm)Males (full grown)
Map turtle7 to 8” inches (20 cm)Females (full grown)
Red-eared slider7 to 12” inches (30 cm)Full grown
15 to 20 yearsSnapping turtle19 to 20” inches (51 cm)Full grown

What Affects A Box Turtle’s Growth Rate?

For any animal, growing is a direct reflection of environmental and dietary factors. 

Basically, if you get the stuff you need, then your body is able to put it to good use and build bones, muscles and body tissue. 

The healthier the turtle, the better its chances of growing and developing to its full potential.

Let’s examine some of the biggest factors affecting growth rates in box turtles.

Varied Diet and Protein Intake

Box turtles require a varied and balanced diet. 

They are opportunistic omnivores. 

This means they’ll consume what happens to be available to them, and they eat both vegetation and animal proteins. 

An adult box turtle’s diet consists of 50% vegetables and fruits and 50% proteins (mainly insects like earthworms, crickets, slugs, snails and others).

Baby box turtles are much more carnivorous than their adult counterparts. 

This is mainly because they’re growing and developing at much faster rates than juveniles and adults are. 

They require larger amounts of proteins to help them build robust bodies and shells. 

As babies grow older, vegetation becomes a much more integral part of their diets.

Below is a list of animal proteins appropriate for frequent box turtle consumption:

  • Earthworms
  • Waxworms
  • Slugs
  • Beetles
  • Grubs
  • Sow bugs
  • Slugs
  • Terrestrial snails
  • Katydids
  • Grasshoppers

The following is a list of vegetables appropriate for frequent consumption:

  • Collard greens
  • Mustard greens
  • Dandelion greens
  • Romaine lettuce
  • Wheat grass
  • Turnip greens
  • Squash
  • Peapods
  • Sweet potatoes
  • Okra
  • Carrots
  • Green beans
  • Wax beans
  • Cactus pad with no spines
  • Red and orange bell peppers

Box turtles can eat many more vegetables, but the foods listed above are the best options for a boxie’s staple diet.

Similarly, here are a few fruits healthy for fairly regular consumption:

  • Figs
  • Apricots
  • Dates
  • Raspberries
  • Strawberries

Fruits should only be approximately 10% of a box turtle’s total vegetation intake, or 5% of its total diet.

Calcium Absorption

Because box turtles can consume such a variety, it’s easier for them to get all of the vitamins and minerals they need from their food than it is for some other types of reptiles. 

However, it’s not a bad idea to occasionally sprinkle a mineral supplement on captive box turtles’ food.

Calcium is extremely important for turtle health. 

It promotes bone and shell health and allows turtles’ bodies to stay strong.

Without proper calcium levels, box turtles may develop a condition called Metabolic Bone Disease (MBD). 

This is a serious illness with symptoms like extreme lethargy, loss of appetite and bending or brittle bones. 

It can become fatal if it’s not treated.

Young turtles with MBD will stop growing.

Enclosure Temperature And Lighting

Being able to regulate body temperature reduces stress levels in box turtles. 

Because turtles are ecotherms (cold-blooded), they require external heat sources to raise their temperature. 

They also require the ability to move away from those heat sources when they need to cool themselves down.

The enclosure temperature should change by about 10° degrees Fahrenheit (6° C) from one end of the cage to the other. 

Depending on the species of turtle, temperatures should range between 70 and 90° degrees Fahrenheit (32° C).

A basking spot should be the warmest place in the tank. 

It should have direct lighting from an overhead heat bulb and be between 85 and 90° degrees Fahrenheit (32° C).

 Keep the light on for 12 to 14 hours each day, then turn off the light at night.

Other indirect heat sources will probably be needed in the enclosure as well, especially when the heating lamp is turned off at nighttime. 

Elements like heating rocks are not appropriate for box turtles because they could easily burn themselves. 

Instead, heating pads or heating tape is a much better solution.

Pet box turtles raised indoors require UV lighting (with both UVA and UVB rays). 

This lighting must be direct, about 18” inches (46 cm) from the turtle.

UV lighting helps with vitamin D3 production, which in turn allows the body to absorb and utilize calcium.

Proper Hydration

Water is an essential part of all box turtles’ natural habitats. 

Drinking, soaking and swimming is necessary for them.

Be sure to provide access to clean, fresh water at all times.

A wide and shallow water bowl is the best option for box turtles. 

It must be large enough for the turtle’s body to comfortably fit in it all at once (even better if it can swim around). 

The water should be no deeper than the turtle’s head when it’s slightly retracted.

Baby box turtles can become dehydrated in a manner of minutes. 

Dehydration can mean certain death for little ones, and it surely doesn’t do their healthy growth and development any favors. 

The consistent presence of water is one of the single most important aspects of your pet turtle’s habitat.

Humidity levels contribute to proper hydration.

While the exact level varies between species, the humidity should generally be between 60% and 80% in the turtles’ enclosure.

Misting your box turtles with a water spray bottle every day or two is another simple action which can greatly benefit your pets and keep them well hydrated.

Enclosure Size and Space

Too small of a living space will stunt a box turtle’s growth. 

Box turtles require a fairly large amount of space: approximately 12’ square feet (3.7 sq m) for up to two turtles.

If you have the means, housing your box turtles outside (even if only for part of the year), is best. 

Box turtles grow and develop in a more healthful manner, and they have a noticeably longer and better quality of life, when they spend time outdoors.

An enclosure with transparent sides is also not the best choice for box turtles. 

They can become quite stressed when they see movement outside of their tank. 

An enclosure made from opaque material like plastic or plywood is a much better choice.

As an example of the size and space required, consider the eastern box turtle. One requires a 75-gallon tank. 

For each additional turtle, add another 40 to 60 gallons.

Brumation Schedule

Brumation is the reptilian version of hibernation. 

It is not as deep of a sleep as hibernation is for mammals. 

But it does significantly, if not completely, shut down a turtle’s metabolism. 

This means when a turtle brumates, it will become almost completely inactive and will no longer digest food until it awakens.

Turtles who brumate tend to grow at slower rates than those who don’t. 

Because they don’t take in any nutrients for about three months out of the year, they have a long break from the consistent growth and development a non-brumating turtle may experience. 

This isn’t necessarily a bad thing.

However, captive box turtles don’t have to brumate. 

They will only do so when they are triggered by consistently low temperatures, between about 50 and 60° degrees Fahrenheit (15.5° C).

Other Stressors To Avoid

In addition to good husbandry practices like those detailed above, here are a few other possible stressors which are easy to avoid:

  • Lack of privacy: include hiding places in the enclosure.
  • Inability to burrow: use loose and soft substrate which allows your turtles to dig.
  • Excessive handling: box turtle’s generally do not like to be held or handled by people. 
  • Exposure to predators: make sure the enclosure is protected from predatory animals, whether they are outdoor natural predators or other indoor pets like cats and dogs.

While these individual factors aren’t known to stunt growth or cause developmental problems, they are stress factors. 

Stress is unhealthy for any animal and most certainly does have an effect on proper development and well-being.

Final Thoughts

Young box turtles grow an average of 1” inch (2.5 cm) a year, but their growth slows as they age. 

Generally, a box turtle will be a full-grown adult by the time they reach an age of 7 to 10 years, measuring anywhere from 4 to 8” inches (20 cm) long.

It is no real surprise how good husbandry and growth rates are connected. 

The very health and well-being of box turtles are greatly affected by how well their owners care for them. 

In turn, their overall health affects their abilities to take in nutrients and build strong bodies. 

As a box turtle owner, part of your responsibility is to provide for your pet. A proper diet, combined with ideal environmental conditions like lighting, temperature, hydration, living space and brumation schedules, are essential factors for your turtle’s ability to grow and develop. 

With good husbandry, you shouldn’t have to worry about how quickly your turtles are growing, or whether they are growing at all. When their needs are covered, they will develop into healthy, happy, full-grown adults!