In the wild, tortoises would obtain the bulk of their calcium requirements by feeding on calcium rich plants and by accidently obtaining sand and soil particles when feeding. They would also seek items in their environment such as snail shells, carrion and often excrement from other animals. In captivity tortoise diets are typically far lower than is seen in the wild. Much of the soil will be rich in minerals from the surrounding rocks such as limestone. Particles will be weathered into the soil providing high calcium rich plants. Many tortoise keepers have noticed a preference to weeds and plants which are purposely grown in calcium rich soil to those grown in regular potting compost.

Limestone Flour is used to supplement the growing weeds or to use as a vitamin supplement for your tortoise diet. Sprinkle their food with Limestone flour two-three times a week for additional intake.