How to repot a houseplant without killing it

Houseplant being lifted from its pot showing a dense root ball ready for repotting

Repotting is one of those tasks that gets put off until a plant is visibly suffering, and then gets done in a rush with whatever pot and soil happen to be lying around. Both of those things cause problems. The putting-off means the plant spends months root-bound, growing slower than it should. The rushing means the plant goes into a pot that's too big, in soil that holds too much water, and starts declining in ways that look like a completely different problem.

This guide is how we handle repotting at the greenhouse. It's not complicated, but the details matter more than people expect.

When to repot

Not on a schedule. The "repot every spring" advice is too broad. Some plants are happy in the same pot for three years. Others outgrow their container in eight months. Here are the actual signs that a plant needs repotting:

Roots coming out of the drainage holes. This is the clearest sign. If roots are poking through the bottom, the plant has run out of room.
Water runs straight through without being absorbed. When the root ball is so dense that soil can't hold moisture anymore, the water just channels down the sides of the pot and out the bottom. The plant stays thirsty even though you just watered it.
The plant is top-heavy and tips over easily. The root system hasn't grown to match the foliage above it, usually because it's been circling at the bottom of a too-small pot.
Growth has stalled despite good conditions. If light, water, and temperature are all fine but the plant hasn't produced new leaves in months, check the roots. A root-bound plant puts its energy into maintaining existing foliage rather than growing.
You can see a dense mat of roots when you lift the plant from the pot. If the root ball holds its shape perfectly when removed, that's a root-bound plant.

Spring and early summer are the best times to repot because the plant is entering its active growing season and will recover faster. Repotting in winter is riskier because the plant is semi-dormant and slower to bounce back from root disturbance.

Choosing the right pot size

Assortment of terracotta and ceramic pots in various sizes arranged on a garden shelf

The most common repotting mistake is going too big. A plant in a 6-inch pot should go into an 8-inch pot, not a 12-inch pot. The reason: soil that isn't occupied by roots stays wet longer. A small root ball sitting in a large volume of damp soil is a recipe for root rot.

The rule is simple: go up by 1 to 2 inches in diameter. For small plants (4-inch pots and under), go up 1 inch. For medium and large plants, go up 2 inches. That's it. If you're tempted to skip sizes because the plant seems like it'll "grow into" a bigger pot, resist the urge. You can always repot again in a year.

Drainage matters more than the pot material

Terracotta, ceramic, plastic: they all work. Terracotta dries out faster because it's porous, which is good for plants that hate wet feet (succulents, snake plants, ZZ plants). Glazed ceramic and plastic hold moisture longer, which suits plants that like consistent dampness (ferns, calathea). But the non-negotiable is drainage holes. A pot without drainage holes is a pot that will eventually kill the plant. Full stop.

Soil types: one mix does not fit all

Bagged "houseplant soil" from the hardware store is fine for most common houseplants (pothos, philodendron, spider plants, peace lilies). But if you're growing anything that has specific drainage needs, you'll want to amend it.

For aroids (monstera, philodendron, pothos): Standard houseplant mix with a handful of perlite and orchid bark mixed in. The bark creates air pockets that aroid roots love.
For succulents and cacti: Use a cactus/succulent mix, or make your own by mixing regular potting soil 50/50 with perlite or coarse sand. The goal is fast drainage. These plants rot in soil that stays wet.
For ferns and calathea: Standard houseplant mix with extra peat moss or coco coir for moisture retention. These plants like consistently damp (not wet) soil.
For orchids: Don't use soil at all. Orchid bark or sphagnum moss. Orchid roots need air circulation and will rot in standard potting mix.

Whatever mix you use, it should feel light and fluffy when dry, not dense and heavy. Compacted soil suffocates roots. If you squeeze a handful of moist soil and it holds together in a tight ball that doesn't break apart, it's too dense. Add more perlite.

The repotting process, step by step

Water the plant a day or two before repotting. Moist roots are more flexible and less likely to break during handling. Bone-dry roots are brittle. Soaking-wet soil is heavy and messy. Aim for the middle ground.
Prepare the new pot. Put a small piece of mesh or a coffee filter over the drainage hole to prevent soil from washing out. Add an inch or two of fresh soil to the bottom.
Remove the plant from the old pot. Tip the pot sideways, support the base of the stem with one hand, and gently pull the pot away. If it's stuck, squeeze the sides of a plastic pot to loosen the root ball, or run a butter knife around the inside edge of a ceramic pot.
Inspect and loosen the roots. If the roots are tightly circled, gently tease them apart with your fingers. You don't need to untangle every root; just break up the outer layer so roots can grow outward into the new soil. For severely root-bound plants, make 3 or 4 vertical cuts about half an inch deep into the root ball with a clean knife.
Position the plant in the new pot. Set the root ball on top of the base soil layer. The top of the root ball should sit about half an inch below the rim of the pot. Add or remove base soil to get the height right.
Fill in around the edges. Add fresh soil around the root ball, pressing gently with your fingers to eliminate large air pockets. Don't pack it down hard. The soil should be firm but not compressed.
Water thoroughly. Water until it runs out of the drainage holes. This settles the soil around the roots and hydrates the fresh mix. The soil level will drop slightly after watering; top up if needed.

Aftercare: the first two weeks

Healthy green houseplant in a new pot sitting in bright indirect sunlight near a window

The two weeks after repotting are when things can go wrong. The plant's roots have been disturbed, some fine root hairs have been damaged, and the plant needs time to re-establish itself in the new soil. Here's how to help it along:

Keep it in its usual spot. Don't move a freshly repotted plant into brighter light or a new location. The plant is already dealing with one stress; adding another makes recovery harder.
Don't fertilize for 4 to 6 weeks. Fresh soil contains enough nutrients. Fertilizing a stressed plant with damaged roots risks burning those roots.
Water carefully. The new soil holds moisture differently than the old soil, so your previous watering rhythm may not apply. Check the soil before watering. If the top inch is still damp, wait.
Expect some leaf drop. A few yellowing lower leaves in the first week or two after repotting is normal. The plant is redirecting energy to root growth. Mass leaf loss is not normal and usually means the pot is too big, the soil is too wet, or the roots were damaged more than the plant can handle.

Most plants show signs of recovery (new growth, firmer leaves, perking up) within 2 to 4 weeks. If a plant still looks stressed after a month, pull it from the pot and check the roots. Mushy, dark-brown roots mean rot, which means the soil is staying too wet. Trim the rotted roots, let the remaining roots air-dry for a few hours, repot into a smaller pot with better-draining soil, and cross your fingers.

Common mistakes we see

Repotting a new plant immediately after buying it. Let the plant acclimate to your home for at least 2 to 3 weeks first. Two stresses at once (new environment plus root disturbance) is too much.
Using a pot without drainage. We've said it already, but it's the most common cause of plant death we see, and it comes up every week in customer emails.
Burying the stem deeper than it was before. The stem should sit at the same depth in the new pot as the old one. Burying it deeper invites stem rot.
Repotting in winter. If possible, wait for spring. The plant's metabolism is slower in winter and it recovers much more slowly from root disturbance.

Questions about a specific plant? Email us at [email protected] with a photo and we'll help you figure out the right pot and soil.