|Join us on
for exclusive updates
on travel specials,
Should You Repot Houseplants -- or Not?
By Dr. Leonard Perry, Extension Professor, University of Vermont
How do you know if a plant needs repotting?
Do any of your houseplants wilt between normal waterings? Do the roots
protrude from drainage holes? Has there been little or no new growth? Are
there white salts on the soil surface?
If you answered "yes" to any of these questions, it's probably time to repot.
Generally speaking, young and fast growing plants will need repotting every
six months to a year, older ones every few years.
You can tell when a plant needs repotting by knocking the soil ball out of the
pot and checking the roots. To do this, invert the plant, hold your hand over the
soil and gently tap the pot edge on the table to loosen the soil. If the roots are
exposed with little soil covering them, it's time to repot.
Check Root Color
If your plant isn’t growing or looking well, this is the time to check root color.
They should be firm and often white, with many tiny root hairs covering them.
If brown, or with discolored patches, and mushy, they likely have a root rot—
often from overwatering. If just a few sickly roots, simply prune them off. If
most look sickly, then discard the plant but try making some stem or leaf
What You Need
For repotting, you will need good quality potting soil, available at garden
stores or you can make your own. If buying one, make sure to get one for
indoor or potted plants. Garden soil, or mixes containing it, should be avoided
as they are not suited for pot culture and often keep plants too wet. I often use
a “peat-lite” medium as I used for potting outdoor plants which contains peat
moss, and some perlite (the small white granules) and perhaps vermiculite (the
silvery granules, an expanded mica). A purchased mix also has some nutrition
usually, and lime to raise the soil acidity or pH. If making your own, you’ll
need to at least correct for the latter.
Use Slightly Larger Pot
When repotting, use a pot slightly larger than the one the plant is in currently.
Keep the old potting mix at the same level in the new pot. If white salts, moss
or other growth is on the surface, scrape this off before planting and replace
with fresh potting mix. Don't bury the stem base. Firm the new soil around the
old soil ball, being careful not to pack it down too tightly. Allow at least one-
half inch space from soil to rim to make watering easier and more thorough.
Care for Your Repotted Plant
Don't forget to fertilize, following instructions on the label. Water well, but
don't overwater and don’t let the pot sit in a saucer of water. Obviously you’ll
want to use a saucer if on furniture, just empty it after watering. Keep the plant
in a warm place at least to start so roots can resume growth, but don’t place
directly on a radiator or wood stove. Keep away from drafts, as these keep pot
and soil cool in cold days and nights.
If a plant is too large to repot, “topdress” it every few years. To topdress, scoop
out the top two or three inches of soil, taking care not to disturb too many of
the roots. Refill the pot to its original soil level using a fresh potting mixture.
If your plant is too big already, especially to put in an even larger pot, you may
need to divide off a piece, or divide it into sections, if there are obvious shoots
or clumps of them that can be easily separated such as with the peace lilies.
Many, whether vines like the pothos or an upright cane like the dumbcane or
umbrella plant, may drop leaves as they get older. If your plants get leggy,
you may just need to root a section of stem and then pot this, discarding the
original plant after your cutting is rooted. Those with woody stems such as the
Benjamin fig may be very difficult to root.
To root a stem section about 3 to 4 inches or so, simply remove the lower
leaves, only leaving a few near the tip. Some such as the pothos or coleus root
easily in water, others you may want to stick in a rooting medium which drains
well and has lots of air space. Good rooting media are perlite, vermiculite, and
a 50:50 combination of these two, or even moist sand and peat moss mixed.
Place cuttings in pots, then enclose loosely in a plastic bag out of direct sun.
Check daily for moisture, misting if needed, but don’t keep too wet. After
several weeks, gently tug or pull on the cutting, and if it doesn’t pull out, it is
likely rooted enough to pot.