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When, Why, and How to Repot Your Houseplants

It’s easy to overlook the fact that your houseplant needs a new home, but eventually, every houseplant needs to be repotted. It’s best to examine your plants for signs every week. There are a number of reasons why your plants might need to be repotted. Here’s what to look out for.

  • Roots growing out of the bottom drainage holes: Plants have a growth hormone in them called auxin, located in the underside of the leaves, the stem, and the roots. Ideally, you’d want the roots and the top of the plant to grow simultaneously, but if a plant becomes root-bound, you wind up stunting its growth by not repotting it. Repotting your plant in a pot one size up (once you notice those bottom roots) ensures that the plant grows evenly.
  • Signs of root rot: Root rot occurs when a plant has been overwatered, or left sitting in water. You may notice sagging leaves, leaves falling off, black rot at the soil level, or even fungus gnats. There are different types of root rot and each of these calls for different root treatments but all treatments require a soil change. Your safest standard treatment is to remove the soil and examine the roots to remove whatever looks dead or rotting, spray the remaining root with neem oil, and repot into slightly damp soil. Neem oil works as a nontoxic, environmentally friendly, fairly broad-spectrum fungicide and pesticide. It’s also a good idea to propagate a new plantlet with a healthy clipping to make sure at least a portion of your plant survives.

  • a plant showing signs of root rot, highlighted with circles: wilted leaves, spots where leaves have dropped off, a dark ring on the stem near the soil line, wet soil
    Signs of root rot, clockwise from left: wet soil, spots where leaves dropped off (3), dark ring on the stem at soil level. Also note the wilting leaves. Photo by Michelle Inciarrano.

  • Lack of growth or top-heavy growth: Sure, that peace-lily looks good, but it’s been the same size since its last growth spurt when you repotted it two springs ago. This would be normal if a plant has reached its maximum size, but if it's still only a foot tall after three years and you want it to keep growing, you’d best repot. Soil becomes less nutritious over time, so an infusion of fresh soil, plus a larger pot, should create another growth spurt. Sometimes a plant will grow in a way that outpaces its roots and will become top-heavy, with stems and leaves that are bigger than what the roots in its small pot can support long-term. A move to a larger pot will help it grow more proportionally.

  • a peperomia plant in a small white pot
    The top of this peperomia plant has grown much larger than its root system, so it needs to be repotted. Photo by Michelle Inciarrano.

  • A return indoors after being outside: If you set your houseplant outside in the spring and bring it back indoors in the fall, you should repot it to avoid pest infestation. Pests have up to a 90-day gestation period. That’s right— 90 days. Before repotting, it’s best to dip the plant in diluted neem oil to drown any eggs. Eggs hide on the underside of the leaves, predominantly, so be sure they are covered. When you repot, use fresh soil.

How to Repot

Once you’ve concluded that your plant needs to move to a new home, here’s how to proceed.

potting soil, pebbles, uprooted plants, and pots
Supplies for repotting a plant, plus a separate plantlet. Photo by Michelle Inciarrano.

Supplies

  • Soil: Repotting a houseplant requires a bit of matchmaking. You’ll need to know what soil is best to ensure the plant gets the right moisture and nutrition in its new home. Most houseplants do well in a standard potting mix but some have different needs. The easiest path is to take a good look at the soil your plant came in. This should tell you a little about its moisture needs. For instance, if your plant is potted in predominantly peat moss, you’ll know this plant likes more humidity and moisture retention. You can also do a little internet research. Succulents will require succulent soil, which has gritty sand, perlite, and vermiculite. Some plants need more peat moss or coir (coconut fiber) to hold water. If you don’t want to mix your own, don’t fear—most home and garden stores sell plant-specific soil that contains the right fertilizer.
  • Pot: You’ll also need an appropriately sized pot. For a root-bound plant or stunted plant, it should be a step up from its current pot, but not overly large. For instance, if the plant is currently in a 3-inch pot, you’d want no larger than a 5-inch pot to replace it. This ensures even growth and minimizes the chance of root rot, which can occur when there is too much extra soil. If the plant needs a portion of its roots removed due to root rot, downsize instead.

  • a variety of potted houseplants near a sunny window
    Plants need the right-sized pot in order to thrive. Photo by Michelle Inciarrano.

  • Drainage particles: If the pot does not have drainage holes, you’ll need to create air pockets at the bottom with a layer of river stones, broken pottery, glass, or clay marbles. This will allow those roots to get needed air and create a place for excess water to go so the roots don’t remain submerged. Allow for this drainage layer when choosing a pot. The less room you leave for drainage, the more the plant will retain water. Conversely, if there is significant drainage the plant will dry out quicker.

Method

Water your plant about a half hour before repotting. You can vary the time amount (it can be three hours before or 15 minutes), but the plant will definitely require an earlier watering to minimize the chance of plant shock.

Add the drainage layer to your pot. You’ll want to keep it less than a quarter the height of the pot itself, though that can vary based on specific plant needs.

Next, add a layer of new soil. This gives the roots some fresh nutrition as they grow downwards.

Now, carefully remove your plant from its old pot. Place one hand around the bottom of the plant (where it meets the soil) and the other hand on the base of the pot. Gently turn the plant over so that you’re mostly using gravity to push the plant out of the pot. If it’s a plastic or coir pot, you can gently squeeze until the plant pops out.

Once the plant is upside down in your hands you can loosen the soil. You want to be gentle, but definitely thorough in spreading those roots. Unless there’s a problem with the soil, it’s good to retain some of it in the new pot so the plant is encouraged to grow toward the new nutrition source. Keep in mind that a plant can easily survive losing up to one third of its roots, so don’t get too caught up in trying to preserve each and every root. Your ultimate goal is to allow the roots to spread freely through their new pot.


a hand placing a plant into a pot
Hold the stem upright when repotting. Photo by Michelle Inciarrano.

Place the plant in its new pot, and hold the stem upright while you add soil around it. It’s important to allow room for watering so be sure to leave half an inch to an inch on top. If there isn’t enough room to safely water it, start over and edit the drainage or pot size. Do not “dome” the soil—the plant should sit level with the soil so that all of the roots receive the same amount of water.


a plantlet with exposed roots, gravel, a potted plant, a pot filled with soil
A newly repotted croton plant and a new plantlet that can be propagated independently. Photo by Michelle Inciarrano.

Moisten the soil. You should definitely water your plant a little now, but do not give it a full watering. It’s best to wait at least a day since you just watered it before you repotted it.

Place back in its previous environment. Changing location and soil simultaneously can lead to plant shock. Make these changes one at a time, unless the plant is imminent need of both. With a little love, your houseplant can thrive for many years.

Michelle Inciarrano co-authored Tiny World Terrariums: A Step-by-Step Guide and is a continuing education instructor at Brooklyn Botanic Garden.

    Discussion

  • Chris July 24, 2021

    Very helpful and informative. My aspidistra is around a 100 years old. It belonged to my great grandmother and is a much cherished possession. It needs repotting and I will follow the advice given. Many thanks.

  • Maria Ramos March 28, 2021

    This article was very helpful! I also attended the virtual BBG workshop on “How Not to Kill Your Houseplants.” My houseplants have been doing much better after I took the BBG workshop.

  • Suzanne February 25, 2021

    Please send information on repotting African violets. Thank you

  • Iris February 23, 2021

    Thanks this was very helpful.

  • Beverly Richards February 19, 2021

    Thanks for this section. Should I replant orchids when they have alot of those veins growing out of it?

  • Mary February 15, 2021

    Thanks, I found this so useful.

  • Noreen January 23, 2021

    Well I figured out why I constantly have gnats in my apartment since I brought in the plants! Thank you!

  • Rhonda Osman January 20, 2021

    I have really learned a lot from this author. It feels like I have just taken a class on how to take better care of my plants. Please have more articles from this author. Looking forward to learning more and implementing new techniques into my life.

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