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gtarman

Terracotta pots and tips for the cactus-confused

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Just thought I'd share my experience...I've found that cacti grow much better for me in terracotta pots than in plastic pots.

In the plastic they stayed too wet too long, and got too hot around the roots. After re-potting the same plants into terracotta, all have thrived.

I think I might actually just share a few things I've learned from when I first started growing cacti to help out any cactus newbies who might benefit...I used to suck at it and my plants struggled. Now they're all coming along nicely, although I wouldn't claim to be an expert. So in no particular order, I've found the 7 simple laws of growing cacti like a boss... :lol:

1. Keep your potting mix simple. After heaps of mucking around I now use Torsten's ratio of roughly 70/30 potting mix and coarse river sand (the potting mix screened out for bark chunks, the sand sieved in water and dried to make it "coarse sharp sand". I'll also throw in a handful of Alroc granular mineral fertilizer as well most of the time, seeing as cacti love their minerals.

2. Only water in the growing season, and only when the soil is dry or almost dry. If the cactus looks like it's having rot problems, discontinue watering altogether until it dries out and heals up. The habit of over-watering is hard to break, especially when you come to growing cacti after growing tropicals or even just regular veggies that like lots of water etc.

3. Mulch your plants with a layer of river stones or smooth quartz, gravel etc - I've found this helps a great deal in establishing a nice consistent moisture cycle...so that the soil doesn't dry out straight away or become hydrophobic, or get baked by the sun. You can add more stones or remove some to fine-tune the cycle if it's drying out too fast or not fast enough.

4. Fertilize! This one is something it took me ages to start doing, but I think it's one of the most important things. Like the potting mix - best to keep it simple. Now I use seaweed emulsion one week, and fish emulsion the next alternating right through the growing season, and it works a charm. If your cacti don't seem to be growing, try this!

5. When planting an unrooted cutting, don't water it in - in fact don't water it at all until you get new growth starting on the tip. A cactus generally throws out roots using just the water it stores in it's body and the moisture of potting mix straight from the bag is more than enough to help it along. When it doesn't have roots, it has no way of using more water anyway, so you're likely to just cause rot problems if you try.

6. Also, don't put a plant without roots in direct sun - it's much more likely to get sunburned.

7. If you're not sure about something or you feel you don't know enough about something, search the forums for more information, and if you can't find it, just start a thread and ask - learning from other people's mistakes saves you heaps of time and frustration, and makes your cacti endeavors a lot more fruitful and rewarding.

Peace,

Gman

Edited by gtarman
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Been wanting to change to terracotta pots for some time now

plastic is just so cheap tho, ill def try grab a few soon.

Thanks

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Really useful info to a newbie like me while definitely get some seaweed emulsion and fish emulsion.

My one cactus is in a terracotta just cause I thought it was nicer looking than plastic.

I have heaps germinating at the moment but it will be a while before potting up.

Cheers Gtarman

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Good advice for sure! Thanks for sharing! I use terra cotta for all my cacti except pereskiopsis. They seem to do better in plastic pots. I'm guessing his has to do with their love of tons of water.

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Nice nooby guide. Im sure many will get benefit from this.

Terracotta is too expensive for me and i use perlite at 20-30% in my cactus mix so i dont have water problems. The pebbles as top dressing are a great idea esp if you live somewhere ultra dry like the west coast.

Ive been using less and less "potting mix" in my cactus mix. If i have enough course sand i use peat (coco coir), sand and perlite with a handful or 2 of potting mix.

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Terracotta is a bit more expensive if you buy the bigger sizes...but definitely worth it IMO. And you can find it for free or for very cheap a lot of the time in old distended yards and gardens or looking through gumtree classifieds etc, or asking at a nursery for old ones.

And RE: potting mix - that probably works well. But I'd discourage newbies from experimenting and making their own mixes until they've mastered the basics and grown for a couple years...when I was just starting out I fumbled around attempting to do variations of my own custom mixes based on what I'd read for way too long instead of just sticking to what works and my plants suffered for it.

I guess that would be my last tip for newbies - if you're not already having decent success and/or you haven't been growing for a while, stick to the basics - and don't experiment or deviate from it until you've been growing successfully for a couple seasons, if you decide to deviate at all. Mixing and matching things based on what many different people say is a recipe for disaster (I did that), and if you don't know the rules in the first place you ought not to try and break them generally (I tried that too).

The reason it took me so long to start using the generic recommendation of 70/30 is kinda because I have a somewhat contrarian outlook, and I'm always looking for alternative, less mainstream, "better" and more sophisticated ways of doing things. But the lesson I learned largely is that while there are many, many recipes for potting mix that can potentially work (probably as many as there are people who grow cacti), a newbie should adopt the attitude of "if it ain't broke, don't fix it", and not try to re-invent the wheel. And at the end of the day the 70/30 mix works really well :)

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Nice tips Gman, very nice indeed :)Some comments I'd like to add if I may.

A sandier ratio is good for un-rooted cuttings, and a mix that is higher in organics (ie Torsten's ratio) is better for potting-up a plant that already has roots.

Also, many people like to begin by starting their fresh unrooted cutting in a plastic pot (with sandy mix) for just a few months, and then pot up into a bigger terracotta pot with a higher organic containing mix such as Mr-T's. It's a pretty good technique.

Lately I'm experimenting with a 'sand' that is actually half washed river sand and half fine blue metal crusher dust. ie 50:50 mix of the two. They call it 'loam' or 'Top-dressing' for lawns. It's pretty common and it's damn good. Give it a go if you get the opportunity.

Also, many people do have success with plastic pots in general and some people even prefer them, so terracotta is by no means essential, but like you I certainly prefer them, for a number of reasons.

I especially like the way the fine roots hug to the walls of the terracotta pot so closely. However when I "plant-out" I don't like to tear the roots from the walls of the terracotta, I simply crack the pot a few times (carefully) with a hammer and plant the whole thing, pot and all. I even do this if I'm just 'potting-up" into a larger pot. The roots come straight through the cracks and the plant keeps powering on.

I also put a layer of busted up terracotta in the bottom of each pot for drainage, and I always add some busted up terracotta to my mixes ( about 5 -10 %). It's a great additive as it holds just a little water (less than perlite), and so is a little charcoal as it keeps the ph nice, but now we're getting a little less simple and even more expensive.

One can often find cracked pots at the potshop or dump for next to nothing. Broken terracotta 'crocks' are quite a useful garden resource.

So anyway, I don't mean to clutter up your nice simple tips but I just had to give terracotta a spruke. I can't speak highly enough of it, a great technology for the cacti grower. Have a play with it some time :)

PS. I am by no means an expert, and I don't mean to come across as a know-it-all.

Cheers big ears :)

Edited by Halcyon Daze
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Also, many people do have success with plastic pots in general and some people even prefer them

Lies! :lol:

Those poor, misguided individuals haha

EDIT: the sandier soil for planting thing might be overkill though IME...I've been planting all my cuttings straight into the 70/30 mix for the last year or so now and haven't had any problems at all. Saves me having to double-handle/re-pot them anyway...once a year is more than enough for those spiney sadistic bastards to tenderize my hands and forearms lol

Edited by gtarman
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One my first go at potting up my cacti I used a mix of approximately 70/30 potting mix and perlite. Everything seemed fine to start, but then I started to loose a few plants. I discovered that when I thought I was watering/fertilising, I actually wasn't. The perlite had made my soil so hydrophobic that the water merely soaked the first 1-2mm and ran down the edges of the pot, leaving the root system very very dry. Now I have to bottom soak each plant just to make sure it gets a drink! Definitely switching to torstens 70/30 potting mix and river sand medium for the next re-potting.

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Perlite might have more of that effect than river sand just due to particle size - it actually holds more water on it's surface as a material, but the particle size is so large that it really aerates and separates the potting mix, which is already quite prone to drying out and becoming hydrophobic by its nature.

Cacti mixes tend to become hydrophobic easier than other potting mixes though because of the added drainage we give them. Which, IMO isn't really a bad thing, I think it's good for a cacti mix to be slightly hydrophobic, as long as it gets re-wet often enough.

Perlite does have some other problems though which is why I don't use it - namely its buoyancy...unless you water very, very slowly and evenly (most people don't do this carefully enough) you'll slowly notice over time that all the perlite will float towards the top of your mix. I don't think this kind of movement in the rootzone is very healthy or natural for plants, which is why now I only use grit that has a bit of weight to it, that won't float...but like I said, that's why my advice to people is to just start with Torsten's recipe - it's simple, it works, and there's very little that can go wrong with it :)

EDIT: also, the mulching is an important factor in the whole hydrophobia thing. A mulch stops the moisture from escaping too quickly and helps keep the soil more consistently moist after watering.

Edited by gtarman

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I've been using scoria as mulch for a few reasons.

- It allows you to blast the pot with the hose without disrupting the soil

- It appears to hold in a bit of moisture but not too much.

- It's a nice dark earthy reddish colour when wet and lighter when dry, so you can tell if the plants need water

- It looks good in both black plastic pots (which is what I'm using) and terracotta.

- It holds the cactus up nicely without crowding it or allowing moisture to stay on the cactus

- You can get it in different sizes - I currently use roughly 10mm chunks for any cactus over 5cm

It's annoying if you spill any on say concrete or hard ground and forget to clean it up, you really know it when you've stepped on a piece in bare feet!

I used to under water and under fertilise my cactus for the first year or two of growing. Now I pretty much fill the pot with water till its running out the bottom every day, and have even fertilised with Powerfeed full strength daily during the growing season and in hot weather and the cactus absolutely love it. I've only had rot on un-rooted cuttings from overwatering as you mentioned above. It is pretty dry down here though...

As for terracotta - I only have a couple in terracotta and it doesn't seem to make much difference (apart from looks - they look fantastic). I'd need a few more and some of my bigger plants in them to really tell I guess.

Edited by IndianDreaming

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Thanks for the advice gtarman, much valued.

I have seen scoria in the nursery before and thought it would be a good top dressing, I'll give it a burl.

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Thanks for sharing, this is definitely gonna help. I'm sure I've heard most of these tips before, but having them posted up here to refer to is really handy!

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There is some really good info in this thread. I'd just like to discuss the terracotta vs plastic debate.
Terracotta is great to grow in but a real shit to repot. The plant roots tend to stick to the sides of the pot making it hard to remove. I usually use a blunt knife or machete to get them out. They are also expensive and break easily. Other than that terracotta is great.
Now plastic. Black plastic heats up, heats up a lot, never water your plants if you are expecting some really hot weather, the roots will stew. It is cheap and readily available. If you live in a big city where the council still does the old fashioned hard rubbish thing. You will never run out of 6 and 8 inch pots again.
White plastic is awesome! it doesn't heat up anywhere near as much as black, all that white goodness just soaks up the heat but that power comes with a price. White plastic degrades really quickly. Most colored plastics are really tacky but I really like the terracotta colored ones, they don't heat up as much as black and don't degrade anywhere near as quickly as white. They are however a bit rare.
Anyway, just a few thoughts. Great thread!

Edited by prier
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+1 for terracotta here gtarman.

I've always loved terracotta, aesthetically as well as practically. (hence the user name :wub: )

I find that my bunnings always puts one size of pot on sale for a buck or two every now and again, and I stock up when I see them.

I also helped out the little old lady who lived near me to clean up her garden one day and as a reward she gave me all her pots that were lying around, as well as a few Orbea variegata that she thought I'd like.

Good little write up here, everything that I had to learn the hard way in one convenient location.

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I pretty much only use terracotta,it's just got so many advantages over plastic I believe.does anyone know where to buy scoria from in west aus??

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I have searched every where i could think of for scoria here with no luck.

Cheers

Got

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I think it's mined on the East coast mainly right? Down in Victoria somewhere primarily if memory serves me correctly...for what they charge for it it's probably not worth shipping it to the West coast...either that or there might be quarantine concerns..?

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I have searched every where i could think of for scoria here with no luck.

Cheers

Got

Hey Got

Did you ever have any luck with your search?

I have only found it via special order at Bunnings

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For what it's worth, if any NZ'ers are reading this - teracotta is the DEVIL over here. Both thin 5mm pots and thick 20-40mm teracotta is awful.

They dry out far too fast, meaning you water more often, and all your nutrients leach out through the pots, leaving them in need of repotting on a yearly basis.

Plastic pots are where it's at. Particularly with an inch or so of small pebbles/riverstones in the bottom for drainage. Black or terracotta colour doesn't make too much difference to their longevity. I've had both last 5+ years without needing to repot the plant.

This is based on my experience with over 100 columnar cacti, both in a greenhouse, and outside in sunny positions in Auckland, over the past 10 years.

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