Repotting 101: When and How

Repotting 101: When and How

I used to think repotting was just something you did when your plant looked sad. Turns out, waiting until a plant looks unhappy is usually too late. Last spring, I finally repotted my pothos that had been in the same nursery pot for two years, and the roots had literally formed a solid mat at the bottom. I felt terrible. The plant had been trying to tell me for months that it needed more space, but I didn’t know what to look for.

So let me share what I’ve learned about repotting, because honestly, it’s one of those things that sounds scarier than it actually is. Once you know the signs and the basic steps, it becomes just another part of plant care.

Signs a plant is root bound

The first time I heard someone say their plant was “root bound,” I had no idea what they meant. I pictured roots tied in knots or something dramatic. In reality, it just means the roots have run out of room and started circling around themselves inside the pot.

Here’s what I look for now. The most obvious sign is roots coming out of the drainage holes at the bottom. I check my plants every few weeks by gently tipping them and looking underneath. If I see thick white or tan roots poking through, that’s my cue.

Another thing I’ve noticed is when water runs straight through the pot without soaking in. This happens because the roots have taken up so much space that there’s barely any soil left to hold moisture. I had this happen with a snake plant last year. I’d water it, and within seconds the water would pour out the bottom. The plant wasn’t drinking it because the soil couldn’t hold it anymore.

Sometimes the soil level drops noticeably in the pot. As roots grow and old soil breaks down, you end up with this gap between the soil surface and the rim of the pot. According to research from the University of Minnesota Extension, this breakdown of potting medium is normal over time, but it’s a signal that your plant might benefit from fresh soil and more space.

You might also see roots circling around the top of the soil or even pushing the plant upward out of the pot. I’ve had small plants literally start to lift themselves up as the root ball expanded. It looks weird, like the plant is trying to escape.

Growth can slow down too, even if you’re doing everything else right with light and water. When a plant is root bound, it can’t take up nutrients efficiently anymore. My monstera stopped putting out new leaves for months, and when I finally repotted it, the roots had completely filled the container. Within a few weeks of repotting, it pushed out three new leaves.

One last thing I check is whether the plant dries out way faster than it used to. If you’re suddenly watering twice as often as you did six months ago, the roots might have displaced most of the soil.

Choosing the right pot size

I made a huge mistake when I first started keeping plants. I bought this beautiful big ceramic pot for a small philodendron because I thought “more room equals happier plant.” Wrong. The plant sat in wet soil for weeks, and I nearly killed it with root rot.

The rule I follow now is simple: go up only one pot size at a time. Usually that means about 1 to 2 inches larger in diameter than the current pot. So if your plant is in a 6-inch pot, move it to an 8-inch pot at most.

Why not give it a huge pot and be done with it? Because plants need their roots to have contact with soil that dries out at a reasonable pace. In an oversized pot, the soil stays wet for too long, especially in the areas where roots haven’t reached yet. That’s when root rot sets in. I learned this the hard way, and the North Carolina State University Extension backs this up in their guidelines on container gardening.

There are a few exceptions. Fast-growing plants like pothos or spider plants can sometimes handle a slightly bigger jump, maybe 2 to 3 inches. And if you’re planting multiple small plants together in one container, you have more flexibility. But for most houseplants, stick with the modest increase.

I also think about the material of the pot now. Terracotta breathes and dries out faster, which is great for plants that like to dry out between waterings, like succulents or snake plants. Plastic and ceramic hold moisture longer, which works better for moisture-loving plants like ferns. I keep my calatheas in plastic pots because they’re dramatic about drying out.

The weight matters too if you’re someone who moves plants around for better light (guilty). Terracotta gets heavy, especially in larger sizes. I have a few big plants in plastic nursery pots that I keep inside decorative ceramic cache pots. That way I can lift out the inner pot to water in the sink without throwing out my back.

Above: A close up look at the symptoms.

Importance of drainage holes

This is non-negotiable for me now, though I didn’t always feel this way. I used to think I could just be careful about watering and skip the drainage holes for prettier pots. I killed at least three plants this way before I accepted reality.

Drainage holes let excess water escape. Without them, water accumulates at the bottom of the pot, and your plant’s roots sit in it. Roots need oxygen to function, and when they’re waterlogged, they essentially drown. Then root rot sets in, which is incredibly hard to reverse once it starts.

I’ve read tips about using a layer of rocks or pebbles at the bottom of a pot without drainage to “create drainage,” but according to soil science research, this actually makes the problem worse. It creates what’s called a perched water table, where water sits in the soil right above the rock layer instead of draining away. The University of Illinois Extension has written about this myth, and they’re clear that it doesn’t work.

If you absolutely love a pot that has no drainage hole, use it as a decorative outer pot (a cache pot) and keep your plant in a plastic nursery pot inside it. After watering, you can lift out the inner pot, let it drain completely in the sink, and then put it back. I do this for several of my plants, and it works perfectly.

Some people drill drainage holes into ceramic or terracotta pots, and I’ve done this a few times with a masonry bit. It’s not hard, but you have to go slowly and keep the bit wet to avoid cracking the pot. I’m not confident enough to try it on expensive pots, but for cheaper ones, it’s worth attempting.

The size and number of drainage holes matters too. One tiny hole in a large pot isn’t going to cut it. I look for pots with several holes or one larger opening. The water needs a clear path out.

Steps to repot safely

Okay, here’s where I walk you through the actual process. I usually repot in my kitchen because it’s easier to clean up, but you could do this outside or in a bathroom if that works better for you.

First, I water the plant a day or two before repotting. This might sound counterintuitive, but moist soil holds together better than bone-dry soil, and it’s easier on the roots. The plant is also less stressed when it’s hydrated.

Get your new pot ready. Make sure it’s clean, especially if you’re reusing an old pot. I rinse used pots with a diluted bleach solution (about 1 part bleach to 10 parts water) and let them dry completely to kill any potential pathogens from previous plants.

I put a small amount of fresh potting mix in the bottom of the new pot. Not too much, just enough so that when I place the plant in, the top of the root ball will sit about an inch below the rim of the pot. This gives you room to water without overflow.

Now for the tricky part: getting the plant out of its old pot. I turn the pot on its side and gently squeeze the sides if it’s plastic. Sometimes I tap the bottom. For really stubborn plants, I run a knife around the inside edge to loosen the root ball. If the plant is huge, I sometimes need help from my partner to hold the pot while I pull the plant.

Once it’s out, I look at the roots. If they’re circling around the outside in a dense mat, I gently tease them apart with my fingers. Some people use a knife to score the root ball vertically in a few places, but I’m usually too nervous to do that. The goal is just to encourage the roots to grow outward into the new soil instead of continuing to circle.

I place the plant in the center of the new pot and fill in around it with fresh potting mix. I use my fingers to gently firm the soil, but I don’t pack it down hard. Roots need some air space. As I add soil, I turn the pot to make sure it’s filling in evenly on all sides.

The soil level should end up at the same height on the plant stem as it was in the old pot. Don’t bury the stem deeper or leave roots exposed at the surface.

Finally, I water thoroughly until water runs out the drainage holes. This settles the soil and eliminates air pockets. Some soil will settle over the next few days, and I might add a bit more to fill in any gaps.

Above: The tools you need to fix this.

Handling transplant shock

Even when you do everything right, some plants get cranky after repotting. This is totally normal. You’ve disturbed their roots and changed their environment, and they need time to adjust.

In the first week or two after repotting, I’ve seen leaves droop, turn yellow, or even drop off. It’s stressful to watch, but usually the plant recovers. My fiddle leaf fig dropped three leaves after I repotted it, and I was convinced I’d killed it. But it bounced back and actually started growing faster than before.

Here’s how I help plants through this transition. First, I don’t fertilize right away. Fresh potting soil already has nutrients, and fertilizing a stressed plant can damage the roots. I wait at least a month before adding any fertilizer.

I keep the plant in its usual spot with the same light conditions it’s used to. This isn’t the time to move it to a brighter window or change its routine. Consistency helps.

Watering is where I have to pay the most attention. The new soil holds moisture differently than the old compacted soil did, so the plant’s watering schedule will probably change. I check the soil more frequently in the first few weeks to get a feel for the new drying pattern. Research from the University of Georgia Extension notes that recently repotted plants often need less frequent watering initially because they have more soil volume and fewer active roots.

Some people mist their plants or use a humidity tray after repotting, especially for tropical plants. I’m honestly hit or miss with this because I forget, but it can help reduce stress on the leaves while the roots re-establish.

If the plant looks really stressed, I sometimes trim off any damaged or dying leaves. They’re not going to recover anyway, and removing them lets the plant focus its energy on new growth instead of trying to support struggling foliage.

Most plants show signs of recovery within a few weeks. You’ll see new growth, the leaves will perk up, and the plant will generally look happier. If a plant is still declining after a month, something else might be wrong. I’d check for root rot, pests, or environmental issues at that point.

The best thing I can tell you is to be patient. I’ve learned that plants almost always take longer to recover than I expect them to. But giving them time, keeping their care consistent, and resisting the urge to “fix” them with extra water or fertilizer usually works.

Repotting really does get easier with practice. The first few times I did it, I was so nervous that I’d hurt the plant. Now I actually find it satisfying, like giving the plant a fresh start. And honestly, most plants are tougher than we give them credit for.

References

North Carolina State University Extension. “Container Gardening.” NC State Extension Publications.

University of Minnesota Extension. “Houseplants: Potting and Repotting.”

University of Illinois Extension. “Container Gardening.”

University of Georgia Extension. “Growing Indoor Plants with Success.”