The joys of repotting my first cactus :-(

Hi,

So i've just repotted my first two catus today. Infact it was probably one of the first plants i've repotted but I messed it up. Basically i put the Cactus mix in, then "dug a hole", placed the cactus in and filled it up with the mix. Wrong. I watched a you tube video and it actually suggest to hold the cactus and push the soil between the roots so they aren't "squashed" and can spread out. It took me a few goes to get it right.

Is that how most of the people do it here? I have a Trichocereus pasacana which was very awkwark. It's about a foot tall and prikly. I managed to suspend it up long enough by holding it underneath to get soil in between the roots. I think it would be much easier with two people. Once it gets bigger thats going to be fun :-(

Now that both cactus's are done, should I wait for a week before watering? It's going to be hot and the soil was very dry.

I'm interested to hear how more experienced people do this rather awkward task!!

This is how I repot a plant.

I put a few layers of newspaper over the hole to keep the soil in, to about 3 or 4 cm up the sides, and then I put a layer of soil in to the level where I think that the lowermost roots should naturally be at the time of repotting. You don't need plastic screening or other stuff which just gets tangled in roots - the paper will remain intact until the soil starts to become held together by growing roots, and you can ignore what might be left of it at any repotting time in the future. A wonderful application of biodegradability.

If you don't have a helper, leather gloves for really spikey plants, or a folded up strip of newspaper for less spikey plants, help to keep them in position as you add the soil. A small trowel with a distinct side-to-side curve will help to pour soil exactly where you want it, or in an emergency a dustpan will work.

I hold the plant up at the final level that I think it should be at, carefully arrange the roots so that they are basically spreading as they should once they're potted, and pour about half of the remaining soil all around the plant's hanging roots. I've seen some people just rest a plant on the bottom layer of soil, with its roots all bunched, and then add more soil; but then when they lift up the plant to its proper height the roots are stretched and often break. It's much better to hold, from the outset, the plant where you want it to be, even if it's awkward (it's easier with a bit of practice), and then start pouring some of the soil in.

Once you've poured the first half of the remaining soil in, and whilst you're still juggling the plant to keep it centered, vertical, and at the right height, gently tap the pot up an down a few times to settle the soil around the lower roots. This works a treat to move the soil into the lower spaces, and it will also start to hold the plant firmly in place. I usually try to hold both pot and plant with each of my hands when I tap - it's difficult to explain, but easy to show.

If the plant needs any minor adjustment to height or centering it might be possible to move it now, though if you've held it well this should be unnecessary. Its verticality might still be a bit off, but at this point it's easy enough to begin adding the last of the soil at positions around the plant to move it back to vertical, all the while tapping the pot up and down gently to firm the soil, or to use a finger if it doesn't push directly on the roots.

If you're working with a largish root ball that has a lot of retained, bound, old soil, you can chip away some of the outer soil, but usually I wouldn't remove all of it - in these circumstances it is harder to manoeuvre new soil back into the root ball without using a 'dibble stick', and unless you're working with healthy roots on a robust plant and you know what you're doing, this is a recipe for pushing off roots. If you are caught in the circumstance where you do have to remove most of the soil, using a spray bottle to skirt a stream of water at the soil can really help to get the new soil into the deeper spaces, although if you're working with a plant that has waterlogging stress, this might not be a good idea.

By this stage all you should really need to do is to pour around the last of the soil, and give the pot a few more gentle knocks up and down. At any point none of these knocks really have to be hard - just enought o settle the soil. Best to do more gentle knocks than a few hard ones.

When finished, you should have 1 to 2 cm of space between the top of the soil and the rim. Sometimes I fill to the rim, because the soil will settle when you water, but I've been caught out and had no more settling - the result is that it's hard to water the plant in one go because the water will just run out of the pot, and if you have scores, or hundreds, of pots to water the time waiting for the water to soak in to a full pot can be excessive! It's better to leave the last few cm, and if you really do need to add a bit more soil, do it after you've watered the plant.

If you're potting at this time of year (southern hemisphere summer) you should definitely water it straight away, unless perhaps if you have a stressed, waterlogged cactus. If you're doing an emergency repot in winter you can usually forego a watering, because the potting mix will be more than moist enough as it is.

Anyway, that's basically my method. It works well for me, but I'm sure others have different ways to do it!

WoodDragon wrote:

This is how I repot a plant.

I put a few layers of newspaper over the hole to keep the soil in, to about 3 or 4 cm up the sides, and then I put a layer of soil in to the level where I think that the lowermost roots should naturally be at the time of repotting. You don't need plastic screening or other stuff which just gets tangled in roots - the paper will remain intact until the soil starts to become held together by growing roots, and you can ignore what might be left of it at any repotting time in the future. A wonderful application of biodegradability.

If you don't have a helper, leather gloves for really spikey plants, or a folded up strip of newspaper for less spikey plants, help to keep them in position as you add the soil. A small trowel with a distinct side-to-side curve will help to pour soil exactly where you want it, or in an emergency a dustpan will work.

I hold the plant up at the final level that I think it should be at, carefully arrange the roots so that they are basically spreading as they should once they're potted, and pour about half of the remaining soil all around the plant's hanging roots. I've seen some people just rest a plant on the bottom layer of soil, with its roots all bunched, and then add more soil; but then when they lift up the plant to its proper height the roots are stretched and often break. It's much better to hold, from the outset, the plant where you want it to be, even if it's awkward (it's easier with a bit of practice), and then start pouring some of the soil in.

Once you've poured the first half of the remaining soil in, and whilst you're still juggling the plant to keep it centered, vertical, and at the right height, gently tap the pot up an down a few times to settle the soil around the lower roots. This works a treat to move the soil into the lower spaces, and it will also start to hold the plant firmly in place. I usually try to hold both pot and plant with each of my hands when I tap - it's difficult to explain, but easy to show.

If the plant needs any minor adjustment to height or centering it might be possible to move it now, though if you've held it well this should be unnecessary. Its verticality might still be a bit off, but at this point it's easy enough to begin adding the last of the soil at positions around the plant to move it back to vertical, all the while tapping the pot up and down gently to firm the soil, or to use a finger if it doesn't push directly on the roots.

If you're working with a largish root ball that has a lot of retained, bound, old soil, you can chip away some of the outer soil, but usually I wouldn't remove all of it - in these circumstances it is harder to manoeuvre new soil back into the root ball without using a 'dibble stick', and unless you're working with healthy roots on a robust plant and you know what you're doing, this is a recipe for pushing off roots. If you are caught in the circumstance where you do have to remove most of the soil, using a spray bottle to skirt a stream of water at the soil can really help to get the new soil into the deeper spaces, although if you're working with a plant that has waterlogging stress, this might not be a good idea.

By this stage all you should really need to do is to pour around the last of the soil, and give the pot a few more gentle knocks up and down. At any point none of these knocks really have to be hard - just enought o settle the soil. Best to do more gentle knocks than a few hard ones.

When finished, you should have 1 to 2 cm of space between the top of the soil and the rim. Sometimes I fill to the rim, because the soil will settle when you water, but I've been caught out and had no more settling - the result is that it's hard to water the plant in one go because the water will just run out of the pot, and if you have scores, or hundreds, of pots to water the time waiting for the water to soak in to a full pot can be excessive! It's better to leave the last few cm, and if you really do need to add a bit more soil, do it after you've watered the plant.

If you're potting at this time of year (southern hemisphere summer) you should definitely water it straight away, unless perhaps if you have a stressed, waterlogged cactus. If you're doing an emergency repot in winter you can usually forego a watering, because the potting mix will be more than moist enough as it is.

Anyway, that's basically my method. It works well for me, but I'm sure others have different ways to do it!

Ahh i think i see what you're getting at. You place the cactus IN the newspaper, put it in the pot and add soil as you go along. So you'd dig a "hole" in the pot, then put the news paper and cactus in adding the soil. Hard to explain i know, but i think i can see what you're getting at. That might actually work!! I did this at 10pm last night. It was really annoying me and I wanted to fix it. Next time though, I'll get the misses or my mum to help!! I'll hold the cactus where I want it and then they can shovel soil into the roots and around until it reaches the desired hight. However, the soil that i'm using is excellent mix so hopefully i'll just be able to losen some roots then pot it next time.

I've just taken your advice and water both the cactus'. I gave them a fairly good soaking. It's rather warm here at the moment (about 30C with lots of wind). I'll give them another water next weekend.

Thanks for your help!!

WoodDragon wrote:

If you're potting at this time of year (southern hemisphere summer) you should definitely water it straight away, unless perhaps if you have a stressed, waterlogged cactus. If you're doing an emergency repot in winter you can usually forego a watering, because the potting mix will be more than moist enough as it is.

I'm a novice cactus owner and I've always read (and been told) that you should never water a cactus immediately after repotting in case the roots have been damaged during the process in which case watering can cause root rot. Apparently the cactus should be left for a week to allow any damage to heal prior to watering.

I'd be interested in others' opinions as I want to be sure I'm doing things the correct way

I read this as well. However the soil that I was using was dry and the cactus hadn't been watered in a very long time. I wasn't too sure but gave it a water anyway. It's a Tri Pasacana and from what I've read they are pretty hardy. The weather in Melbourne looks like it's not getting any higher than 27 this week. So I'll test the soil on the weekend again, and if it's damp i'll leave it for another week. Then i'll give it a good soaking the follinging week. Am I doing this right?? We shall see.....

I started to create some diagrams to explain how I do it, and then I realised I'd be reinventing the wheel. Sure enough, I found this using Google. It pretty much says what I do to hold a cactus, although there are a few differences.

To clarify something above, I don't 'dig a hole' at any time. The whole point of repotting is to avoid digging holes in the first place - these just make it harder to get the roots in the right position! My first step is to add about as much soil as the last figure has in broken terracotta pot chips. I don't bother with the chips themselves or with the moss - a few layers of newspaper will do, as I explained before.

To repeat - put as much soil in the bottom layer as you need to just touch the bottom-most tips of the roots as you hold the cactus exactly where you want it in its final position. This layer is flat - it's not a hole! Then, holding the cactus in this position, fill as I described earlier and as the second last figure illustrates, although try not to tip the cactus to one side or another as you add the soil. Fill to about the point where it says "potting soil" on the last figure, then gently knock the pot up and down as I described. Once you think that the soil has settled into the lowermost spaces and the cactus is still where you want it, add the rest of the soil and settle it too.

With experience you can do the soil-adding in incremental stages, although this means that you'll be holding the plant for a bit longer.

I have very freely draining mix and I pot into terracotta, and I repot in warmer weather, so my pots dry out after the watering before rot becomes an issue. I've never had any problems with watering a cactus in, and given that it's a big help in settling the plant I feel comfortable doing it.

I only water the once for the first week or so, and because diesel's plants are already a few days past potting it shouldn't be too much of an issue - they do a lot of their callussing (if roots are damaged) in the first day or two.

And once you get the hang of it, hopefully you won't break many roots during repotting in the first place!