Obtain a pot one-size larger or no more than 2 inches bigger than the pot holding the spider plant. Transplanting is best done while the spider plant is actively growing from spring to fall.
Place a coffee filter in the bottom of the pot to cover the drainage holes. This will hold the potting soil inside the pot. Put the pot on a drainage tray. Fill the bottom of the pot with potting soil.
Turn the pot holding the spider plant upside down to remove the plant. Inspect the roots and cut off any damaged or frail roots. Pull apart any encircling roots, or make several vertical cuts around the root ball.
Place the spider plant in the center of the new pot and adjust the level of the soil beneath the roots, if the plant is setting below the rim of the pot. The idea is to have the transplanted spider plant in the new pot at the same level as the plant was previously growing.
Fill the pot full with potting mix. Soak the plant with water to remove any air pockets and to firm the soil against the spider plant's roots.