Summarize this article:

Meyer lemon trees are the best and most adaptable tree for growing inside. They produce plenty of small or medium fruits and their maintenance level is more friendly for beginners.  Pink variegated lemon trees also grow well indoors and are beginner-friendly. Buy a lemon tree at least 2-3 years old, as young trees may not grow as well indoors. Although you can grow lemon trees from seed, they are less likely to adapt to indoor climates and will not produce the same as their parent tree. Plastic pots are ideal for lemon trees so you can move the plant around as the seasons (and light sources) change. Look for a plastic pot with plenty of depth to help your tree balance as it gets larger and produces fruits.  The pot depth determines how large the lemon plant can grow. About 15 gallons (57 L) is the minimum recommended pot size.  Choose a pot that has drainage holes to prevent your plant from getting waterlogged. Place a few pebbles or gravel on the saucer and add a little water before placing the container on the saucer and the pebbles. The water-filled saucer will help maintain a trace amount of humidity around your tree. You can cut a strip of landscaper's cloth and place it at the bottom of the pot to keep it from leaking dirt into the saucer. Replace the cloth when you transplant the tree so you don’t clog the hole. Lemon trees grow well in peat moss mix because it is mildly acidic and well-draining. Buy it or another acidic, well-draining soil mix from a nearby garden center or plant nursery. Soils meant for cacti will also work well for citrus trees. Lemon trees grow best when they have at least 8-12 hours of direct sunlight. Choose a spot by a window where your plant will get direct sunlight all day. If you're in a location that doesn't get a lot of sun, set up a grow light near the plant and leave it on for up to 12 hours a day. Massage the roots with your fingers, gently pulling them apart with your hands. This will help its roots spread faster get more nutrients and water from the soil. Pull carefully to avoid damaging or breaking off the roots. Before planting your lemon tree, add about 1/2 of the soil mix to your pot and smooth it over until even. This will help your lemon tree's roots grow into the soil and help it stay upright as you place it in. Position it upright in the pot and fill the rest of the pot with soil. Press the soil around the plant's base down, making sure that no roots are left exposed and out of the soil.  Bury the tree at the same level as it was in the older pot. Avoid covering the trunk with soil, as this can cause fungal infections. Moistening the soil will help make it more habitable for your plant as it adapts. Water the tree until the soil is damp, but not soaked or waterlogged.

Summary:
Pick Meyer lemon trees for growing indoors. Choose a deep plastic pot for your lemon plant. Find a saucer large enough to fit beneath the container. Buy a slightly acidic potting mix for your tree. Find a sunny spot for your lemon tree to grow. Take the lemon tree out of its nursery pot and spread its roots. Fill the pot halfway with soil mix. Place the lemon tree in the pot. Water your tree immediately after planting it.