Answer: Once your avocado seed sprouts both roots and a top sprout, plant it in a soil-less seed-starting mix in a 4-inch pot. (Don't use garden soil--it may harbor various pathogens that can cause young seedlings to rot.) Be sure to leave about 1/4 of the seed showing above the soil line. It sounds as if you may have overwatered the plants. Try keeping the new seedlings in a bright spot, and water when the soil surface is dry to the touch. Wait until the plant has several sets of leaves before fertilizing..
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