The carob tree is a broadleaved evergreen native to the eastern Mediterranean areas and features shiny green foliage with long pods that produce edible seeds commonly substituted for chocolate. The carob tree grows to heights of up to 50 feet if left to grow in the ground. Since the carob tree is a slow-growing tree, many gardeners enjoy potting the carob and growing it indoors in a sunroom or under grow lights.
Rub the hard outer coating of the carob seed with a piece of sandpaper. This process is scarification, and it weakens the outer shell, making it easier for the interior carob seed to sprout for germination.
Fill a bowl with warm water, and place the carob seeds into the bowl. Soak the seeds in the warm water for 24 hours. The carob seeds must swell before they are ready for planting. If the some carob seeds did not swell, then repeat the soaking process a second time.
Spread a 2- to 3-inch layer of clean sand into a small 3-inch container. Dampen the sand with a light spray of water and push the swollen carob seeds 2 inches into the sand. Set the container in an area where temperatures remain above 18.3 degrees Celsius.
Keep the sand moist with water until the carob seeds begin to germinate and sprout. Obtain a planting container at least 24 inches in depth to transplant the carob seedling into. Carob trees produce a long taproot that travels down deeper into the soil than the other roots.
Fill the container with a good quality potting soil containing added amendments such as compost, peat moss or sand. The soil needs to drain well for the developing carob tree.
Remove the carob seedling from the sand and plant it into its new planting container. Place one carob tree seedling per each planting container. Use your hands to tamp the soil down around the carob seedling to ensure the carob tree is securely in the soil.
Water the soil surrounding the young carob tree seedling with a gentle stream of water from a watering can. Allow the soil to dry between watering.
Move the carob tree to a sunny location indoors such as in front of a southern-facing window, under artificial grow lights or in a sunroom. The carob tree requires temperatures to remain above 18.3 degrees Celsius for maximum growth potential.
Fresh and soft carob seeds recently obtained from a carob tree will not require any pre-germination treatments. Only carob seeds that have dried and developed the hard outer shell require pretreatments. Carob trees grown indoors in smaller pots can be trained as miniature carob bonsai trees.
Growing carob trees indoors may substantially reduce or eliminate its production of carob pods.