Grow your own lemon tree directly from the seeds of a lemon purchased at the local grocery store. Lemon trees can be grown indoors and make beautiful houseplants, and eventually produce citrus fruit. Plants can be grown outdoors as well, or where temperatures do not fall below 54 degrees. Lemon trees need plenty of light, and require up to 12 hours of light at times. The lemon tree may eventually grow up to 20 feet in height. Planting a lemon tree only requires several steps; find a fresh lemon and get ready to plant.
Remove lemon seeds directly from the lemon fruit prior to planting. Do not allow the seeds to dry. According to New Mexico State University's publication "Southwest Yard and Garden," tropical plants, including the lemon, must be moist in order to properly germinate. Wash the seeds to remove any of the lemon fruit and dab dry with a paper towel. Washing is necessary to discourage and decrease mold and mildew on the seeds.
Plant the seeds in soil that has been heat-pasteurized. Sterilize and pasteurize potting soil by heating the soil to 160 degrees for 30 minutes. The heating process destroys harmful organisms that may be living on the potting soil. Heat-pasteurized potting soil can be purchased; however, a bag of soil that has been open for a lengthy period of time--or homemade compost, if used--should be heated. Dave's Garden suggests using a heat-proof roasting bag or closed container to avoid an unpleasant odor escaping from the oven during the process. Allow soil to cool prior to planting.
Use old pots, foam or yogurt cups for potting; make irrigation holes on the bottom of the cups for soil to drain. Place the potting soil in small containers until full. Make a ½-inch indention into the soil and place one seed per cup in the hole; cover with soil. Add a small amount of water to the cup to lightly moisten the soil and cover the cup with plastic wrap. The plastic wrap will keep both the soil and the cup moist and humid. Always keep soil moist, but never soggy. Place the containers in a windowsill or other warm spot (such as on top of the refrigerator) for warmth; sunlight is not necessary until the seed sprouts and pushes through the soil.
Transplant the plant once it has outgrown its small container to a container twice the size of the original. The plant must be transplanted continuously, as a lemon tree can grow up to 20 feet in height. Fruit will not be produced on the lemon tree for about 15 years, unless it is grafted with a mature lemon tree.