Grown for their velvety, rounded leaves and bright, five-petalled flowers, African violets (Saintpaulia spp.) first made their appearance in Africa during the late 1800s. This tender herbaceous perennial grows outdoors in U.S. Department of Agriculture plant hardiness zones 11 and higher, but it makes an excellent indoor potted plant in any zone when given the correct care. As African violets mature, their lower leaves die, leaving a long, bare stem. At first this bare neck only detracts from the plant's appearance, but if left for too long without transplanting, it will negatively affect the African violet's health.
Necks Shorter Than 1 1/2 Inches
Withhold water from the African violet until the soil dries to a depth of 2 to 3 inches. Slide the plant carefully from its pot. Snip off any dead, dry or shriveled leaves still attached to the bare portion of stem, or neck, using a pair of pruning snips. Make each cut as close to the stem as possible without cutting or otherwise injuring it.
Remove the outermost layer of dried, brown tissue from the portion of stem located between the soil level and the plant's bottom-most leaves using a knife. Drag the knife's blade down the stem, shaving the tissue off. Do not exert excessive pressure on the blade to prevent cutting the stem too deeply.
Brush off a layer of soil from the bottom of the African violet's root ball, equal in depth to the length of the plant's neck. For example, if the neck measures 1 inch long, then remove 1 inch of soil from the root ball's bottom. Remove a 1/2-inch-wide layer of soil around the entire root ball's perimeter.
Select a pot with a width equal to one-third of the plant's total leaf-span and a depth 1 to 1 1/2 inches greater than the distance from the root ball's bottom to the point 1/4 inch below the bottom most leaves. Use a pot containing drainage holes. Fill the pot with a 1/2-inch layer of potting soil, tamping it down.
Place the African violet's root ball in the center of the pot. Add or remove soil from the pot as needed to position the point on the stem that is 1/4 inch below the bottom leaves at 1 inch below the pot's top. Fill the pot with soil, tamping it down around the sides of the root ball and the stem's neck. Fill the pot with soil to 1/4 inch below the plant's bottom leaves.
Fill the pot slowly with water from a watering can. Wait for the water to soak completely into the soil. Fill the pot one to two more times with water until the soil becomes thoroughly moist, but not soggy.
Place the plant in a room that receives at least 12 to 14 hours of bright, indirect sunlight, and that maintains a constant daytime temperature of 75 to 80 degrees Fahrenheit and a nighttime temperature of 62 to 65 degrees Fahrenheit. Position the plant in bright, indirect sunlight away from heating and cooling vents.
Necks Longer Than 1 1/2 Inches
Cut off any dead or damaged leaves from the African violet plant with a pair of pruning shears. Remove any flower buds or blooms. Cut off any dead leaves clinging to the 2-inch portion of bare stem, or neck, located below the lowest healthy leaves. Shave the outermost, brown, dried layer of tissue from this same portion of stem using a knife. Scrape the tissue off carefully and gently to avoid cutting too deep.
Select a pot identical in size to the violet's current pot. Choose a pot that contains drainage holes in its bottom. Fill the pot to 1-inch below its top with potting soil. Tamp the soil down to remove excess air pockets. Add additional soil if needed to maintain the correct level.
Cut horizontally through the plant's stem at soil level with the pruning shears. Poke a 1 3/4-to-2-inch deep hole with your forefinger in the center of the new pot's soil. Insert the bottom 1 3/4 to 2 inches of bare stem into the hole, positioning the plant with its leaves parallel to the soil's surface. Pack the soil around the stem to hold it in place.
Water the soil in the pot until it feels slightly moist. Spray the inside of a plastic zipper bag with a spray bottle containing 90-degree Fahrenheit water, stopping once both sides hold a thin coating of water droplets.
Place the pot inside the plastic zipper bag and seal the bag closed. Place the bag in bright, indirect sunlight in a room with a constant temperature of 75 to 80 degrees Fahrenheit.
Check the soil in the pot every three to five days for moisture loss. Water the pot when the soil feels dry. Do not overwater the pot to the point that the soil becomes soggy. Mist the inside of the bag if the water dries, but do not allow water to puddle in the bag's bottom.
Tug on the cutting gently, three weeks after the planting date, to test for roots. Reseal the bag if the cutting slides upwards easily. Leave the plant in the bag with the bag open if the cutting remains firmly in the soil. Move the plant out of the bag once all the water droplets evaporate.