What to do (and NOT to do) when repotting so your plants don't die
Ready? Set? Repot! Wait. No. Don't do that. Put down that pot. Take your hands off that scoop. Here's what to do before, during and after repotting, which ideally starts the day before...
But why bother with this extra care? Because repotting for your plant, is like major surgery is for us. Getting in our best health before surgery, allowing the right conditions for recovery, and the right care after surgery, is all just as important for us for a speedy recovery without complications, as it is for our plants.
But before we jump in. Keep in mind repotting and potting up are not the same. Repotting involves the removal of old potting mix, and is best done before or after the growing season (early Spring, late Summer and Autumn). Potting up however is less drastic for a plant, usually involves shifting a plant - old potting mix and all - up a pot size, adding new potting into the bottom and around the sides. I'm personally happy to pot up any time of year, although still tend to avoid winter unless necessary.
Here's what's in this guide. Click to jump to each section, or scroll down to read start to finish...
What could go wrong when repotting?
Repotting, done well, can result in a happier, healthier plant that bounces back quickly. When repotting goes wrong, you could be dealing with root rot or even plant death. The 'best of the worst' is simply that plants stop growing for a while. In between the two extremes, other symptoms of transplant stress from repotting include yellowing leaves, leaf drop, wilting even when watered, no new growth or root damage. These extra two steps will help you give your plants the best chances of a speedy recovery, without complications.
Quick disclaimer: As always with plants, a lot of 'best practice' is trial and error based on what works the best for the most people. This is what works best for my jungle (anywhere from 50 to 100+ indoor plants at any given time as I have a mix of my own collection and plants I propagate and grow for sale), combined with some handy tips and tricks from my mentors (references at the end).
Before you start, you ideally want to grab all of the following...
- Potting mix (whether store-bought or DIY). My current fave is the Bio Leaf potting mix).
- A soil scoop or similar (I often grab a big salad or serving spoon if I can't find my scoop).
- The pot you're potting up into (I'm loving clear pots at the moment).
- A mask (don't breathe in the soil dust, silt or particles!).
- Gloves (and always wash your hands after handling potting mix).
- Seaweed (or a root growth booster)
- Fertiliser (more about these two coming up - these are key to this method).
- A potting mat (totally optional, but wow, what a game-changer for something so simple).
- Water (made into a nutrient solution, more about that coming up).
Is your potting mix still okay to use?
If you've just got yourself a fresh bag of potting mix, skip this section and go to Step 1: Prepare your plant below.
Before you literally dig in, keep in mind old potting mix might not be ok to use. You won't always find an official 'expiry date' or 'best before' stamped on the bag, but you should aim to store unopened potting mix no longer than about 6 months in ideal conditions, if stored sealed, in an air-tight bag or container, somewhere cool and dry. Keep in mind a lot of potting mix are in breathable bags so moisture levels don't build up and go mouldy.
However the more natural and organic your mix is, the shorter the storage. Closed or opened, it's best to use up mixes with organic ingredients within 30 days. As long as it's kept dry, most rock and mineral substrates (perlite, pumice, leca, pon, vermiculite and similar), can be stored long-term and used as and when needed. They don't expire or 'go bad'.
Over time, potting mix can compact, reducing the air space roots need, it can become hydrophobic (where it repels water), and salts in the soil can increase, which can cause fertiliser burn (once potted up, regular watering flushes out excess salts).
What's in your mix definitely changes how long you can store it without it degrading also. The more yummy organic matter is in there, the happier your plant will be, however the sooner you should use up the bag for maximum goodies for your plant. If stored well and you can spot any issues like fungus, bugs or mould, but it's definitely been a while, you can also get fresh potting mix and mix old and new together roughly half and half to save it going to waste.
Bugs and pests (good and bad) are also more likely to set-up home in potting mix if stored for a while. Fungus Gnats in particular love stored soil if moist and warm, as well as fungi itself. You'll sometimes find small white fluffy balls (I think of them as baby fungus), or even mushrooms, growing in old stored potting mix. If stored potting mix gets warm and wet, that can also be an ideal breeding ground for harmful bacteria.
Step 1: Prepare your plant for repotting - with a bath!
Ideally the 4 steps are prep your plant, prep your soil, repotting, then recovery. Most people only do step 3 (repotting). Here's step one...
Make up some nutrient solutions and give your plant a nutrient bath a day or two before you plan to repot. 24 to 48 hours before repotting is ideal. I try to time this with when the plant's due to be watered anyway. You can make your own nutrient solution combo, but for my guys, I use a mix of fertiliser and seaweed. More about these products, how much I use, and other options coming up.
As well as helping to loosen old potting mix attached to the roots, a nutrient bath also helps soften the roots and make them more pliable and less likely to break or be damaged during repotting. The nutrients themselves also give plants a boost of essential nutrients, and help the roots recover better from the stress and shock of repotting.
Grab yourself your usual fertiliser plus either seaweed or a growth-booster that is formulated to support roots. The product guide below gives you a few options. This is what you'll use to make the nutrient solution ready for bath time.
It's bath time! Mix your fertiliser with water. Add either a growth booster, root booster or seaweed (a few options below), and you've made your nutrient solution. Then give your plant a good soak! There are two popular methods:
The bath method is pretty much what it sounds like, and is really just a variation on bottom watering but with nutrient solution. Pop your plant in an outer container, pot and all (no need to remove or disturb the plant at this stage). Fill the outer container up with nutrient solution until the water's at least half way up the pot. Leave the plant to soak for up to 60 minutes maximum, or until the top of the substrate is wet (I find 15 to 30 minutes is usually plenty). Remove the plant and let it drain.
A top water drench is the other way to do this step. Thoroughly top water your plant with nutrient solution until the substrate is fully saturated. I'll usually water heavily until water freely pours out the drainage holes, wait a minute, then repeat again. Give the plant time to drain, and you're done.
A very popular growth & root booster here in NZ is Groconut (also available in Australia). It's made from coconut water and is a natural source of plant growth hormones. When I use Groconut for a nutrient bath, I add a 1/2 teaspoon of Groconut powder per 1 litre of water along with fertiliser.
If you DO have seaweed (or another growth or root booster), but you DON'T have fertiliser, two of my favourite fertilisers are: GT Foliage Focus and Dyna-Gro Foliage Pro
...but any of the Dyna-Gro or Growth Technology fertilisers are superb. For GT I use 5mls GT per 1 litre water, or for Dyna-Gro use 1ml Dyna-Gro per 1.5 litres water, along with seaweed or a growth booster.
If you DON'T have seaweed, or don't want to get two separate products, another goodie is Plant Runner Indoor Plant Food which is both fertiliser and seaweed in one. For that use 1ml Plant Runner per 1 litre water. Bonus with Plant Runner is the top is actually a 1ml pipette, so measuring is super easy as it's built-in.
My usual repotting combo has been both fertiliser (GT or Dyna-Gro) and seaweed (I use the BioPower brand - details below). My plants all get a light seaweed feed once a month, and fertiliser every time I water, so I keep both on hand anyway, meaning I don't need to buy anything special for repotting.
For seaweed, I use BioPower Organic Seaweed at 2 grams seaweed flake per litre of water. That fertiliser and seaweed bath has worked really well for me, which is the method I first learned from one of my mentors, Greg Barnes from Bio Leaf, which he covers in his repotting webinar (see the references section at the end).
However, in my usual fashion of always learning, which means my plants become my guinea pigs and get everything tried on them, I'm currently trialling a new fertiliser (well, new to NZ), that is not just a complete and balanced fertiliser, but also a root growth-booster, formulated to reduce transplant stress and aid both root recovery and initiate new root growth.
It's called GT CCS. The full name is 'Growth Technology Clonex Clone Solution' so you can see why GT CCS is what everyone calls it (and no, it's not Clonex rooting gel, but is made by the same company). For CCS I've been using it at 5mls CCS per 1 litre of water along with BioPower seaweed, but you can just use CCS by itself.
Step 2: Prepare your potting mix
Whatever combination of ingredients you buy or DIY for your potting mix, give it a good shake or mix up first. Multi-ingredient potting mixes (like the Bioleaf custom blend potting mix my plants love), can settle in the bag when stored or during transport, with the fine stuff usually ending up at the bottom.
Pour out how much potting mix you'll need (I used a big mixing bowl, but a bucket's a good option too), and give it a water until lightly moist if it's on the dry side. Water helps 'stick' or bind together all those different ingredients, so once mixed you get an even distribution throughout the pot. Now pot up as you normally do...
Step 3: Repot
For me, this part usually means sliding the plant out of its old pot, and gently removing the old substrate from around the roots (I like using my squeeze water bottle for that). Whatever method you use, avoid damaging or breaking any roots if you can. Shaking the plant or pulling substrate off the roots with your hands can take the roots or delicate root hairs along with it, so I prefer to take it gently and use water to do the job, not force.
If you find the rootball is dense and compacted, maybe it became rootbound before you got around to repotting, you will likely need to loosen that root-ball up gently, so the roots venture out into the new potting mix once repotted. The soak you did a day or two earlier will help soften and loosen roots to make this whole part of the process easier with less damage caused. Sometimes you just have to get rough with those roots, and may break off or damage a few roots in the process. That's where step 4 (recovery) comes in.
...we interrupt our normal broadcasting for a Public Service Announcement
If you hate repotting as much as I do (the mess, the fuss), get yourself a potting mat. This is my #1 must-have. Make all the mess you want. Repot anywhere you want (in front of the TV gets my vote). No more wasting soil. The sides snap together, keeping mess contained. No having to repot in the garage or outside either, just repot when and where you like, tip out the extra soil to use later, and roll it up for next time. Potting mats come in 3 sizes. I prefer the 75cm x 75cm mat myself (that ends up about 65 x 65cm once the corners are snapped together).
My other repotting tip might seem weird, but it's NOT to make your own mix. I absolutely will do that when I have the time, the storage room for all the ingredients, and the energy to bother. But these days the custom blends you can get are seriously fantastic and so thoroughly tested by other plant hobbyists much fussier than me.
My favourite is the custom blend Aroid and Hoya Potting Mix by Bio Leaf for all my established plants. For cuttings, seedlings, propagation and baby plants, I've been loving pure Fern Fibre lately too, and am currently trialling the new Bioleaf Fine / Medium Blend.
Something else I love about both the Bioleaf and Fern Fibre, is minimal mess and easy clean-up. My old go-to of indoor potting mix along with a blend of Perlite and other bits and bobs, was just mess central. You should still wear gloves and a mask though like any potting mix. Health first.
Step 4: Recovery care for your plant after repotting
It feels like all the hard work's done now - and to be fair, the physical stuff is done and dusted - but how well you care for your plants after repotting makes a big difference in how fast they recover and start growing again.
It can be quite normal for plants to temporarily stop growing after repotting, especially if you went up a lot bigger in pot size. What you want to try to avoid is transplant stress, such as yellowing, wilting, dropping leaves, roots that don't recover, root rot or even plant death. No thank you!
Right after repotting
Give your newly potted plant another really good drench or soak with the same nutrient solution you made up for step 1. You can either go for the bath method and bottom water, or thoroughly top water.
I prefer to give plants a bath (bottom water) as step one, a day or two before I repot, then I like to thoroughly top water drench after repotting, as top watering also helps flush out excess dirt and silt from the new substrate.
For the month following repotting
You can just return to your usual water and fertiliser routine after repotting, provided your plant's recovering fine, but I like to keep giving those roots the VIP treatment to help the plant recover. I'm using the new GT CCS to temporarily replace my usual fertiliser for the first month after repotting.
It's still a complete and balanced fertiliser, with no urea or chlorides to reduce the risk of burning roots, but CCS is also a root growth booster, reducing transplant stress and encouraging faster recovery.
WHERE OH WHERE?
Advice about where to put a plant after repotting varies, but I like to return it to the same conditions it was in before repotting, to minimise the amount of change it's dealing with. Some advise keeping plants warmer after repotting, some in a cooler, shaded area. Either way, direct sun after repotting is best avoided for at least a couple of weeks, even if the plant used to get direct sun on the regular.
For my jungle, I tend to baby newly repotted plants. If there's some reason they can't go back to their usual spot, or I'm worried about them, I find them a warm and brighter-than-normal place to call home while they recover. If their new spot is warmer and brighter, that usually means they'll need watering more often also, so I keep a closer eye on them. I do have a heat pad on hand also just in case, but tend to use that for newly repotted cuttings or baby plants.
My jungle gets a monthly feed of seaweed anyway, but for newly repotted plants, I like to give them a weak seaweed and fertiliser mix every time I water, just for the first month or so.
Phew! That covered a lot. It does seems a lot at first, but becomes second nature after the first couple of times you follow this method. Plus I find it weirdly comforting giving my plants this much love, knowing I'm doing everything I can for them to come out the other end after repotting, happier and healthier than before.
PS: This is my favourite custom blend potting mix...
Greg Barnes from Bio Leaf Plant Nutrients, has a webinar called How To Take Care Of Your Plants Before And After Repotting (18 Oct '21) that my version of this method is based on. I highly recommend attending any of Greg's webinars. Follow his Facebook page to watch out for the next webinar.