The ideal soil for cardamom is loamy with a pH level between 4.5 and 7. The soil should be slightly sandy so it drains gradually. You can purchase loamy soil from most garden centers. If you’re planning on transplanting the seedlings to your outside garden, choose a space in the garden with well draining soil. Pay attention to the soil after a heavy rain to see how it drains. You shouldn’t see deep puddles remaining, but the soil should stay moist. If the soil is too rich in clay, it will kill the cardamom plant, so find somewhere else in the garden or mix sand into the soil to break up the clay. If you’re going to leave the seeds in the container and grow the plants to maturity, use a pot that’s at least 1 foot (0.30 m) deep and 6 inches (15 cm) wide. Plant a few cardamom seeds indoors and let them grow for a few months so they sprout above the soil. Transplant the seedlings to a shady place in your yard. It will take several years of watering and nurturing, but your plants will produce cardamom that you can harvest and use in baking or cooking.