Re-Potting Tips

Learn to tell when plants need to be repotted.

  • Topic: Planting Techniques
  • Keywords: pots, containers, re-pot, soil, Planting Techniques, planters
  • Date: February 2002

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If the last time you thought about repotting your houseplants you stayed up till 4:30am plagued by nightmares of soil everywhere but in the pot and dismembered roots causing post-traumatic stress disorder for your Dracaena (with the attendant baleful glances), then you might need a quick primer in painless potting. (And if you think a plant can’t scold, you’ve never met my Dracaena.)

Many people advocate a once a year repotting for plants until they reach mature size, and if you’re an industrious type, this rule of thumb might work for you. Since I’m not, I tend to repot only when my plants tell me they need it.

In their language, this is how they tell you they’d like a new pot:

  • You find yourself watering more and more and your plant is still in perpetual wilt
  • You see roots growing through the surface of the soil and you’re pretty sure it’s not turning into an orchid.
  • When you ease the plant out of the pot there are large roots girding the outer circumference of the root ball
  • The plant is breaking its pot
  • The center of the plant is turning brown and/or dying
  • Your plant is just too big for its pot (losing its balance), or too big for the space in which you want to keep it
  • You can’t remember the last time you repotted

For most plants, the best time to repot is late winter/early spring when the days are starting to get longer, triggering new growth in your plant’s roots and leaves.

Potting Basics:

1.)Gradually increase the pot size—if the plant is currently in a 6” diameter pot, only move it to a 7” or 8” pot. Drastically increasing the size of the pot will not result in a larger, healthier plant. In the case of a large plant (in a 20” pot, for instance), it’s okay to move up in 4” intervals. The pot should have a drainage hole. If the pot you want to use doesn’t have a hole, pot the plant up in a different pot and use the original as a cache pot.

2.)Make sure the pot you are planning to use has been thoroughly washed if it had a previous inhabitant. Use a bleach and water solution (1:9 ratio) to scrub the pot.

3.)If you are using a clay pot, soak the pot in water for a period beforehand, so that the dry terracotta doesn’t pull water out of the soil just when the plant is going to need it the most.

4.)Moisten the soil. You don’t want sopping wet sticky soil, but a powdery soil will not soak up water readily. Put a little water into the potting soil bag or bin and stir it around.

5.)Place a single piece of broken pot in the bottom of the new pot, blocking the drainage hole to prevent soil from falling out. Make sure the rounded side is up, not down, or else it might form a seal which could prevent proper drainage.

6.)Put a little bit of potting soil down over the pot shard, patting it down lightly. The object is to get the plant in its new pot at the same depth it was in the old pot. Remember that you want to keep an inch or so at the top for easier watering.

7.)Remove the plant from its original pot—sometimes this is a bit tricky, but it can usually be accomplished without breaking the old pot. Water the plant well before removing the old pot—the roots are less likely to break or fray if they’re slightly wet. Turn the plant upside down and cradle the surface of the soil, stabilizing the stem between your fingers. Gently tap the pot, or, if it’s in plastic, simply squeeze the sides until the root ball loosens up a bit.

8.)If the roots of the plant are circling around the outside of the soil, mimicking the form of the pot, you’ll need to do some cutting to prevent the plant from strangling itself. Take a knife and cut through the major roots, and score the sides about 1 to 2 inches into the root ball. With a healthy root ball I generally also cut off an inch or two at the bottom of the plant. The tips of the root absorb the majority of water and nutrients for a plant, but the trauma of trimming the roots is quickly overcome by invigorated new growth.

9.)If root ball is not girded and looks healthy (white or lightly colored roots as opposed to black, rotting roots), gently massage the roots as though you were giving someone a head rub. Some soil should fall away, but the roots will hang on to most of the interior soil.

10.)When you have the right height, gently pack soil in around the edges of the plant. The first few waterings will cause the new soil to settle, so you might need to add a little more soil as it compacts.

A few extra pointers:

Choose the right soil for your plant—cacti and succulents require more drainage than most houseplants, so purchase a ready made cactus medium or mix sand in with your potting soil. Other plants that have special growing mediums are orchids and African violets. Other than that, pretty much everything else will work in a standard potting soil. There are many varieties available and they do vary in makeup. A little trial and error will result in a good mix for you. Once you find the right soil, stick with it—potting mixes have different water retentive qualities which can cause stress to your plant if you don’t replant with the same variety of soil every time.

Here at the greenhouse we mix in a combination of organic products such as Yum Yum Mix, soft rock phosphate, greensand and Nature-Gro volcanic ash fertilizer. These aren’t traditional additives but they produce healthy, happy tropicals. We also use a standard root stimulator combo of Superthrive and Seacom in our post-transplant watering. If you prefer to use stronger chemical fertilizers, do not fertilize for the first couple of weeks after repotting or you could burn your plant’s roots.

Remember that some plants actually prefer to be root bound. Slower growing plants like Jades, many cacti and succulents, clivias and orchids resent frequent uprooting. Since the primary reason we up pot is to produce healthy growth, frequent trauma for these plants is counterproductive.

Repotting cacti is always a more painful proposition. Cut a piece from a brown paper grocery sack or cotton cloth into a strip and wrap it around the center of the cactus, then gently grasp the ends and you’ll have a poke-free handle.