Wash the Florida West Indian seed off with warm water to remove any residual pulp.
Attach three toothpicks to the outside of the avocado seed, using a rubber band to hold them in place. Arrange the toothpicks evenly around the seed so that they form a tripod support for the seed.
Adjust the seed to ensure that the pointed end of the seed is facing upward.
Place the toothpick-surrounded seed into a glass cup and fill the cup with water so that the flat bottom of the seed is just touching the water.
Maintain the water in the glass cup so that it is always touching the base of the seed. After a few weeks, the seed should sprout and develop roots.
Place a general potting soil mix into a potting container -- you can start using any size of container for the seedling -- and transplant the avocado seed into the soil.
Maintain soil moisture with regular watering and place the plant in a bright, warm location in your home. You can grow avocado trees as a houseplant or transplant the tree outdoors when the weather is warm.