New to cacti and have many questions about repotting, soil..

[oxygene]

Hello everyone,

I'm pretty new to cacti and have been reading various websites and forums about cacti care, but there's so much information out there that has left me confused! I have several questions about cacti care - I hope they aren't too silly.

While I am new to cacti, I have owned six small cacti for a few months. I didn't do enough research as I should have and ended up killing off one of them and two more are damaged. I still have them, I just haven't repotted them.

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I also have two larger cacti that I very recently bought from a grocery store. I have not repotted them yet. A few weeks ago, I repotted three of the small cacti plants into small ceramic pots.

These are the cacti:

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This brings me to my questions:

Repotting: Are the repotted plants in appropriate-sized pots or are they too small? As for the two larger cacti, would 3" clay pots be okay? The mammillaria pringlei is about 3.5" tall and the mammillaria spinosissima is about 2.25" tall.

Soil: The three small cacti are in a mixture of Miracle Gro cactus soil and the soil they were originally grown in. I know now that peat is generally bad for cacti and Miracle Gro is usually not recommended!

I have read the cactus soil article here on CactiGuide that I'd like to try out, but I'm not sure how to make my own soil. The only "ingredients" I have are the Miracle Gro cactus soil and Miracle Gro perlite. I've never seen coir for sale here (Sask., Canada) and I do not know if the other suggested ingredients would be available locally. Is there any way I could make my own mix with the MG soil/perlite I have and possibly some other ingredients?

Temperature: I live in zone 3a in the middle of the freezing prairies, not exactly the ideal habitat for most cacti. Since the winters here are so brutal, I wouldn't be able to keep them outside year-round. Our summers can be very hot and humid, but the average daytime temperature in the summer is anywhere between 20*C and 25*C (68*F to 77*F), sometimes higher (up to 40*C/104*F). Would it be a bad idea to take them outside in the daytime in summer?

Water: Watering schedules are the hardest thing for me to figure out! I don't know if I should water them once a week, once a month...! Since it's winter where I live, how often should I water them once I get them into new soil?

Thanks in advance!

[CactusFanDan]

Damage on the first plant looks like it's old and healed over properly so it shouldn't be a problem. Not so certain about the damage on the Oreocereus, but damage near the base is never a good thing. You can check things when you repot it, though.

Repotting: That depends on the size of the root system the plants have! I think most growers on this forum agree that you should pot a plant into a new pot which fits the old roots without leaving too much space. However, knowing how many roots tend to come off when you're removing plants from peat, those sized pots might be fine to reuse. One tip for repotting is to remove as much peat/old potting soil as humanly possible, from the roots. It sounds extreme, but it makes a huge difference. If you see SDR's post, he did an excellent job of doing so, here: http://cactiguide.com/forum/viewtopic.php?f=25&t=32534" onclick="window.open(this.href);return false;

Soil: Feel free to use the miracle grow potting soil as the base, but mix it at least 50/50 with the perlite or another aggregate. I think most people use less than 50% of an organic base (coir, miracle grow, peat, top soil etc.) to their mix, but it's partly a matter of taste. I don't like perlite, it's too lightweight and doesn't hold moisture as well as I'd like. I don't live in Canada so I can't comment on what's available, but you might be able to find hard-fired clay cat litter, which is my favourite soil amendment. Alternatively, you can use pumice or granite gravel/grit if you can find it.

Temperature: Probably best to have them outside in Summer. Those temperatures are fine, especially being out in the open. My greenhouse peaked at around 42C last year. One thing to be careful of though, is acclimating your plants to higher light intensity when you move them out. You need to move them into full sun slowly, otherwise your plants will most likely get sunburnt.

Water: Not always an easy thing to judge! But saying that, in a good soil mix, watering every 2 weeks when it's Summer and nice and warm isn't a bad starting point. However what is probably best is to water your plants when they get thirsty, which is very variable! Wrinkling, shrinking, sunken ribs in the growing season (Summer for your plants) are all good signs to water.

I'd hold off water until at least April after you repot them. You should ideally only be watering cacti when they're actively growing, or when you want them to be growing actively. Unless you can give them enough light in Winter for them to grow normally (a lot, more than the natural light available in Winter) then you want them to be dormant so they don't become etiolated. Keeping them cool (5-10C or a bit less) in Winter is good practise too.

[oxygene]

Wow, thank you so much for all that information!

I will definitely try to remove the peat off the roots! Should I do anything different to the two damaged cacti when removing peat, or should I just do what was done in that thread?

Soil mixture: Unfortunately, I don't recall seeing pumice, granite gravel, or hard-fired clay cat litter here. I'll try to keep an eye out, though all our local greenhouses won't open until sometime in March.

Is it safe to repot the three smaller plants in the new soil mixture (after I find out what I want to use in it) or should I leave them alone for a while since I just repotted them a few weeks ago?

As for winter and growing: Right now all the cacti are sitting beside a large south-facing picture window that gets plenty of intense sunlight in the daytime. It always feels colder next to the window at night; right now it's -21*C (-5*F) outside. I don't know what the room temperature is next to the window (it's definitely not -21*C next to the window in the room, but it is cool!). Is it bad for the cacti being next to a cold window?

Also, I took a few more pictures of the damaged cacti, including the one that completely deflated.

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Those large white "scars" near the top were on the plant when I got it.

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I gently touched the wrinkly spots with a toothpick. I was expecting it to be soft and mushy, but it was actually hard! I'm also feeling uncertain about the white spots next to the spines. Are they mealybugs?

And this is the "dead" cactus... I'm really embarrassed by this one!

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I honestly have no idea what happened to it. I watered the small cacti about once a month. A few weeks ago I noticed this one seemed to be slowly shrinking... then it turned into that.

For reference, this is what the cacti looked like when they were brand new with the withered one front and centre:

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I apologize for asking more questions, and thanks again in advance!

[DaveW]

If you scroll down this link evidently the equivalent of the clay cat litter is available in Canada as "Schultz Aquatic Plant Soil", presumably available from aquatic stores rather than garden centres:-

http://www.bonsai4me.co.uk/Basics/Basic ... page4.html" onclick="window.open(this.href);return false;

Obviously it will be only one ingredient of your mix.

[Ivan C]

If you have a NAPA Auto parts store near by you can get oil-dry to use. Check out here for the Canadian part #.

[CactusFanDan]

Just go ahead and remove the peat from the roots. Be sure to keep them in a cool, dry and well-ventilated place if you wet the roots whilst doing so and allow the roots to dry fully before potting them up. The three smaller ones will be fine to repot right now.

I can't see any mealie bugs on any of your pictures, but you might want to give a prophylactic dose of a systemic insecticide in Summer since they're almost always present on those plants in the blister-packs. Hard and dry old damage is a good sign, it means that it's dried up and scarred over fully. I'd say it's old sun damage from the looks of things. Sadly, I suspect the dead one might've been on it's way out when you got it. It's quite common for people to buy plants which look fine in the shop, only to have them rot for no apparent reason. Usually due to the shop not treating them right.

[oxygene]

Thanks for all the help, everyone! I'll try and repot everything (and remove the peat from the roots - hopefully that won't be too difficult!) within the next few days.

[DaveW]

The problem if you only have a few plants and cannot obtain a suitable ready made cactus compost is the individual ingredients often only come in bags large enough when mixed to make up enough to re-pot the whole greenhouse! In that case just mix a commercial cactus compost with about 50% extra grit.

[adetheproducer]

one good method of sourcing soil is to find places in nature you can take a bit that won't be missed/do harm. Under pine or oak trees below the initial mulch layer is good source of humus rich loams, rivers/streems for sands/silts/gravels/pebbles, mole hills or worm casts for rich organic soils. thats what I tend to do but also lot of garden centres will supply small bags of agrigates as well but more expensive.

[CactusFanDan]

Aquarist suppliers sell fairly small bags of gravel and stuff too which it usable. Avoid round pebbles where possible, as they help little with drainage.

[oxygene]

Thanks for the other suggestions, everyone - I'll take a look around some local stores to see if anything else would do. If not, I'll have to stick with the perlite for now.

[sabotenmen]

You really don’t HAVE to use perlite, cat litter, or even pumice. Using pumice or a substitute is a recent practice. Growers have used a combination of loam and gravel for many years and for many species this still works and always will. Pumice would be best, but I would never use perlite. Instead of that horrible perlite, I would follow Dave’s advice and try commercial cactus compost with 50 % grit. You could even use a good quality ordinary soil for houseplants and then mix it with 30-50 percent sharp grit. But look at the amount of peat, 15-20 percent max. Peatless soil would be best and then mix it with coir .I put my large Echinocactus Grusonii in a soil/ grit (50%) mix last spring and they’ve rooted through the medium very quickly and the mix dries out fast enough (although I think that 50% grit is a tad too much!).I’m not sure if you can find what you want in aquarist stores; Dan is right when he says that you should avoid round pebbles, but for fish tanks that’s exactly what they want ,they don’t want sharp grit. So I’m not sure if you would be able to find sharp gravel easily there. Also, grit may be more expensive in aquarium shops. Don’t know about Canada, but I can find sharp grit in garden centers here and it’s cheaper than in aquarium shops.Okay, I'm sorry, I've just read in one of your earlier posts that you can't find gravel/grit where you live. I don't know, I find this hard to believe. Have you checked out some garden centres and pet shops?I'd reckon they sell grit everywhere Please try to find it somewhere. Perlite will not stay mixed with whatever for long, it's useless!

[oxygene]

It's the coir I've never seen in stores. I'm sure there's gravel/grit in stores here, I just don't remember seeing specifically granite gravel/grit. The local greenhouses still aren't open yet but I will try to find something suitable when they open in a week or so. I live in a smaller city so there aren't a lot of pet and garden stores to choose from. As for finding gravel/grit in nature, that wouldn't be easy right now as there is a few feet of snow on the ground! Thanks again.

[CactusFanDan]

It's the coir I've never seen in stores. I'm sure there's gravel/grit in stores here, I just don't remember seeing specifically granite gravel/grit. The local greenhouses still aren't open yet but I will try to find something suitable when they open in a week or so. I live in a smaller city so there aren't a lot of pet and garden stores to choose from. As for finding gravel/grit in nature, that wouldn't be easy right now as there is a few feet of snow on the ground! Thanks again.

If you know any poultry farmers, then you might want to try getting a hold of chicken grit. It's supposed to be quite good - nice, rough pieces.

[Steve Johnson]

If you know any poultry farmers, then you might want to try getting a hold of chicken grit. It's supposed to be quite good - nice, rough pieces.

Yes, but avoid oystershell or eggshell grit -- cacti don't do well with Calcium in the mix. You already know that, so my comment is for those who may not be aware of the difference in grits. Oxygene, make sure you get the right kind.