If you manage to keep alive a houseplant for, oh, more than a few months, there will surely come the day when it has outgrown its starter pot We checked in with Eric Larson, a houseplant wunderkind and manager of Yale Universitys Marsh Botanic Gardens. He walked us through the not-so-slippery terrain of repotting your root-bound houseplant.
Tools required: Old newspapers. Clippers or pruning knife. Potting soil (with vermiculite or perlite). New, clean pot that is no more than 25 percent bigger than existing pot. Garden gloves.
1. Place old newspapers on a flat work space .Gently remove your root-bound houseplant from its too-tight pot; this may require some light nudging.
2. Examine the root ball. Use a pruning knife or closed pruning clippers (your fingers will work, too) to gently tease out the roots, as if untangling a knot of hair you are providing breathing room.
3. Slip your newly untangled/pruned houseplant into its new pot (no more than 25 percent bigger than the old one) to make sure you have at least 1 inch of headroom for every 8 inches of soil, so you can water without water spilling over the sides. Figure out how much potting soil you can tuck into the pot and still have adequate headroom. Now, take the houseplant back out of the new pot.
4. Add potting soil to the bottom of pot. Slip the plant back into its new home, filling in the sides with as much potting soil as you need.