Plant how-to: repotting
Repotting is a necessary skill if you keep houseplants or do any sort of container gradening, yet it seems to make many new plant parents nervous. I’m here to walk you through the process step-by-step! I think a lot of folks are wary of killing their plant in the process of repotting. Personally, I have yet to totally kill a plant via repotting (trust me, I’ve killed a lot of plants, just not this way). Plants can go through a bit of transplant shock, but if you choose the right tools and materials, we can make the operation as un-traumatizing as possible for both you and the plant!
Before you do the actual repotting, you have to determine when is an appropriate time to repot and if your plant needs it. For me and for a lot of other plant folks I know, I don't repot until my plant is rootbound. Rootbound (sometimes referred to as potbound) is a term you'll hear a lot in the houseplant world and is an important concept to understand. Essentially, when a plant is rootbound, it means that the roots have grown so much that there’s no longer space for them in their current container. Typically you'll see that the roots have coiled around themselves and that there is a higher root-to-potting medium ratio. (See below picture for a perfect example.) Now, there are varying degrees of rootbound. Some plants can stand having their roots in a tight pot for a while (for example, Sansevieria spp. and many Hoya spp.) and will show little sign of distress. But most plants will exhibit obvious signs of being rootbound, you just have to know what to look for! If this is the case, it's definitely time to repot your plant to a larger container so that the roots have room to grow. If you notice any of the following signs, gently pop the root ball out of the pot to check the roots & go from there.
SIGNS YOUR PLANT IS ROOTBOUND:
- The roots are bulging over the top of the soil, or snaking out of the bottom drainage holes.
- The pot may actually warp or crack - I had a spider plant (Chlorophytum comosum) last summer that broke the plastic nursery container it came in!
- The potting medium dries out super quickly despite regular watering, or the water isn't absorbed and runs straight through the pot.
- New growth is very slow, despite proper light and nutrition; new growth may also deformed or small. In this case, the roots are so tight and there is so little soil that they can't support healthy new growth.
- Bottom leaves yellow every time you water, even with excellent drainage.
WHEN TO REPOT:
- Check roots in spring to see if the plant needs to be in a larger pot for the growing season; however, you can absolutely repot in the winter if the plant needs it! No need to wait until spring. Just make sure the plant isn't too cold if you repot outside (typically under 50°F).
- There's no need to repot a plant immediately when you bring it home from a store or receive one in the mail. Let it adjust to it's new surroundings and environmental conditions for at least a week or two (if not more), before rushing to change out it's pot. That said, nursery plants are often quite rootbound since they've been in the same pots for a long time & the soil can sometimes be really compacted or too rich. So, they'll need to be repotted eventually, just give them time to acclimate! Repotting too soon can often result in shock, which is something we want to avoid.
HOW TO REPOT:
What you need:
- Potting medium (you may use pre-mixed or mix your own). FYI: I use the terms potting mix, potting medium, and soil interchangeably
- Suitable pot with drainage holes, 2-4" larger than original pot
- Plant of choice
- Watering can
- Optional: gardening gloves (I like to repot bare-handed, but that's my own personal preference); SuperThrive (sort of like a plant multivitamin that helps with transplant shock); small piece of coffee filter/cheesecloth/tulle/screen to place over drainage hole
In an earlier blog post, I wrote about choosing the right container (which you can read about here). To recap: choose a pot 2-4" larger than the original container, and make sure it has drainage holes. I will never be the person who tells you it's okay to layer charcoal and rocks at the bottom of a drain-less pot; that is not a proper way to drain water & honestly could be an entire blog post on it's own! It's up to you what material the pot is; it just depends on your personal preferences and the plant itself! Again, refer to my earlier blog post for more on that. Now that we have everything we need, let's get our hands dirty.
First of all, make sure you have ALL of your supplies handy and that you have enough potting medium - it's really annoying to have to mix more half-way through the process, or even worse, totally run out and have to make an extra trip to the garden center! Things are gonna get messy, so repot outside if possible. If repotting indoors, I like to lay out a large garbage bag on the floor and do all my work there. It makes for easy clean up.
If reusing a pot, make sure it's cleaned thoroughly; if you're using a terra cotta pot, soak it in water the night before. This helps the pot retain some moisture, and the pot won't dry out too quickly in turn. At this point, you can place a small piece of screen/fabric over the hole so that the medium doesn't fall out at every watering. Then place a layer of potting medium at the bottom. How much you layer depends on the size of the pot and plant, but you shouldn't have more than a few inches of potting mix at the bottom.
Pop the plant out of it's current pot, and gently tease apart the roots. You can use your fingers, a fork, a butter knife, chopsticks, bamboo skewers, whatever you have on hand. You just want to make sure that you've loosed those tightly wound roots so that they can spread out in their new home. If there's any root rot (black/dark brown mushy roots), make sure to cut it away with clean, sharp shears & sanitize afterwards. Try not to damage the roots too much, as this can cause stress and shock like I mentioned above. I also like to shake some of the old soil out the rootball, but you don't want to roots to be totally bare. There are exceptions, of course, if you need to totally change out the soil due to a pest infection.
Pro tip: water your plant a day or two before repotting. This helps keep the rootball more intact. Soil that's too dry will get everywhere and fall away from the roots, while a plant that's just been watered will be a soppy mess.
Position the plant on top of the potting mix. I like to make sure my plant isn't settled too low or too high; I've found that an inch or two below the rim of the pot is ideal. You may have to adjust the amount of medium at the bottom to achieve this! And that's okay - eventually you will get a feel for how much needs to be at the bottom.
Gently fill in your potting mix around the root ball using a spade, or even your hands! Fill the pot with potting medium just above the top of the root ball, at the base of the stem. Sometimes broken stems or leaves are casualties of the process, and that's okay. Just try to be careful! A common repotting mistake new plant parents often make is packing the soil in too tightly, which can compact the soil (compact soil = bad; aerated soil = good). What I like to do is lightly pat down the potting medium and then tap the pot against a firm surface to settle any lose soil.
Water the plant thoroughly so that it comes out of the drainage holes. I always water afterwards so that the water will "fill in" any air pockets in the potting medium, and I've also found that it just helps the plant settle in to it's new home by keeping the roots hydrated. Dry roots would cause more stress, in my experience.
Pro tip: Water with Superthrive after repotting to help with transplant shock! Superthrive is like a multivitamin for your plant and I’ve had great successs with it. Make sure to use as instructed on the bottle!
Ta-da! All done! Not as hard as you thought it wokld be, eh? Place your newly potted plant in a shady area for a day or two while it adjusts, then move it to it’s permanent home. Eventually you will have the process down pat & you’ll be able to quickly and efficiently repot plants any time they need it. At this point in my life, I can repot in minutes while my toddler is hanging off of my legs!