Questions tagged [cactus]

Member of the family Cactaceae. Desert succulents.

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15
votes
2answers
4k views

How should I repot these overgrown and delicate plants?

I've got several plants that are probably overdue to be repotted. One of them is a cactus with lots of new growth and sharp spines. And the other is a jade where many more of the cuttings survived ...
14
votes
4answers
388 views

How to manipulate a cactus with thick long spines?

I'm thinking of buying a cactus. Shops have a lot of those and one of the variables is the size and density of spines. Cacti with rare huge spines (something like 15 millimeters long and about 1 ...
12
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3answers
3k views

What should I do if the soil shrinks and separates from the flowerpot walls?

Recently we relocated a cactus into a new flowerpot. When it was planted the soil would evenly occupy the flowerpot and adjoin the flowerpot side walls. The soil isn't cactus soil, but just regular ...
12
votes
1answer
3k views

What is this white growth on my cactus?

I have several cacti growing in my yard and one (t. pachanoi, if it matters) has developed a white layer across the top of the plant. It is very fine and looks almost sandy, like perhaps a mould or ...
11
votes
2answers
653 views

What's a good water system for my cactus plant during holidays?

I have a very resilient cactus that can be left alone for a month without consequences. Now, I want to leave it alone during two months and leave it some water system. I have seen little earthen ...
10
votes
1answer
716 views

Do opuntia (prickly pear) cacti readily form hybrids in the wild?

I suspect the answer is yes, because they are the most diverse group of cacti. The reason I ask is that we actually have four varieties/species and I'm having a lot of trouble identifying them! The ...
10
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2answers
13k views

Why is my cactus purple?

This has been going on for a while (about a year), one of my cacti has turned purple. I've just replanted it after its pot fell and broke (no, it did not spend the year on the ground). What is the ...
9
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2answers
20k views

Why is my cactus droopy?

I have a cactus (pictured) which I bought about a month or so ago. It has been slowly drooping, although the tag said to keep it dry in winter and I have only watered it once when I re-potted it. The ...
9
votes
1answer
276 views

Does Rebutia grow better when grafted onto an Echinopsis?

I have tried growing rebutias before, and failed because the plants lacked vigor and grew slowly. Would they do better if I flat-grafted it onto a columnar Echinopsis, to increase vigor? Are there any ...
8
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3answers
2k views

What cacti can grow without cold protection in USDA zone 6b in Pennsylvania?

I'm in USDA hardiness zone 6b. I'm growing eastern prickly pears as outdoor perennials, and would like to grow some other cacti as well. From what I gather, cold hardiness has a lot to do with soil ...
8
votes
2answers
426 views

What is this cactus with paper-looking spindles sticking out all around?

I bought this cactus a while ago and never knew the name of the species. Can someone help me with the name of the plant? A small clone of it is growing on the top of the plant. Should I cut it and ...
8
votes
1answer
265 views

What is this columnar cactus?

I am trying to identify my cactus that I planted when I xeriscaped last year. I never saved the little stick thing. I thought it was just a saguaro variation, but then it popped out all these red ...
8
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2answers
971 views

What fertilizer should I use on agave and cactus?

I live in Canada, and have several cacti and large agave plants. It's soon going to be time to take them outside as the weather starts to warm up. They are potted in a mix of coir, sand, fast draining ...
8
votes
2answers
325 views

cultivating a cactus from cutting

I've recently gotten a san pedro (Echinopsis pachanoi) cutting as a gift. I'm trying to take care of it as good as possible, but I'm not sure if I'm doing it the right way. The situation is: the ...
8
votes
1answer
419 views

Help is my cactus is dying, can it be saved

I recently bought a golden barrel cactus (about two months ago), judging by its size I would say the plant is about a year old. Everything has been perfect with it until Saturday. I usually water or ...
8
votes
1answer
850 views

Why is my cactus turning purple and pale?

Ever since I got this cactus it has been growing, but now it's becoming purple and paler. What am I doing wrong, and how do I solve it? I'm rather new at this gardening stuff so help would really be ...
8
votes
3answers
116 views

Does anyone know what type of cactus this is?

Hi all, I recently bought this cactus but haven't had much luck identifying it. Any help or ideas would be very much appreciated. Thanks :)
7
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2answers
2k views

Are these 'fluffy' cacti healthy?

My wife and I have had these cacti for a little over a year now. Since change happens slowly I assume we never really noticed, but now it seems like it has gotten a lot more..fluffy.. for lack of a ...
7
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3answers
78 views

When is the winter period for plants kept in a country with no winter (or a constant room temperature)?

Reading up on how to care for a Mammillaria Elongata Cactus I see it mentions such things as suspending watering in winter for best care (and to encourage better flowering) the preferred time to re-...
7
votes
1answer
3k views

Why Hasn't my Cactus Grown Deadly Spines?

I recently purchased a small cactus plant from my local store for about $5. I've been giving the cactus lots of sunlight and a good watering every week. I've noticed that since I bought it, the ...
7
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2answers
170 views

Centering Opuntia Cactus

I originally cut some Opuntia pads I got from a seller into half and planted them in the centre of pots. Unfortunately, they seem to be growing on one side only and I fear they will get too heavy and ...
7
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4answers
1k views

Succulent Disease Identification (kalanchoe beharensis)

Album of pictures Another album of updated pictures One leaf before being "washed" with a mild soap/water mixture Another leaf after being "washed" with a mild soap/water mixture I purchased this ...
7
votes
1answer
832 views

What are these white/yellowish spots on my mexican fence post cactus?

My mexican fence post cactus has developed some sort of white/yellowish fungus(?) on it. Anyone know what it is? I hope it's not a goner!!! Looking for some help to save this guy!
7
votes
1answer
2k views

What is this white crust forming on my cactus during the growing months?

I live in the UK and have a Trichocereus bridgesii/Echinopsis lageniformis "monstrose" cactus that I bought from a garden centre 3 years ago. Every year in early summer several new stems grow from ...
7
votes
1answer
808 views

The age of an Opuntia (prickly pear cactus)

Opuntia, prickly pear cactus, is a hardy plant with a wide range of distribution. Its growth habit is by branching paddles, or nopales. Is there any way to measure or estimate the age of such a ...
7
votes
2answers
2k views

Should I cut off cactus pads to help the main branch to grow?

I have some small cactus (one year old) and they are have been producing a lot of new pads. If I remove the branching pads, the main stem will have more energy to develop itself (my main focus is to ...
7
votes
1answer
718 views

Can any cacti be used as a scion on a non cactus succulent rootstock?

Anything in the cactus family can be grafted onto anything else in the cactus family, even jungle cacti to desert cacti. I've even grafted a Schlumbergera to a prickly pear. I would like to know, just ...
7
votes
1answer
431 views

What is this epiphytic cactus with small orange flowers along the stems?

Does anyone know the species of this epiphytic cactus? Even the genus would be a step forward. Could it be a Disocactus sp.? The open flower is less than 2 cm (just under an inch) in diameter. The ...
7
votes
2answers
565 views

How can I determine if cactus seedlings are dead?

I planted some notocactus seeds sometime in September and many have germinated since then. A few weeks ago, there was an incident where some of my succulents may have experienced frost and I can't be ...
7
votes
1answer
2k views

How to salvage a cactus plant that is half dead

This plant did very well for a year and bloomed. At some point I think I over watered it and it started looking 'dusty' and then parts turned black. I snipped off the worst parts and let it dry out ...
7
votes
1answer
231 views

At what age will a night flowering cereus begin to flower?

I have a night flowering cereus cactus that is about five years old. It is a foot tall and has a single stem. It is in a four inch square plastic pot. Is it going to flower anytime soon?
7
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1answer
5k views

What are these brown patches on my acanthocereus tetragonus (fairy castle cactus)?

I've had this pair of fairy castle cacti for several years now, and they've done fairly well. However, I noticed today that they have developed brown patches over most of their stems and a few areas ...
6
votes
2answers
839 views

Rats like to eat cactus?

Rats like to eat cactus? I have noticed that my cactus has become increasingly gnawed, and I have no idea what can be. I'm starting to take care of gardens recently and do not know much about it.
6
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2answers
5k views

How to grow a new Opuntia (prickly pear) from a cutting?

I cut this pad which grew this summer from my Opuntia and I want to make a new one. I know I have to let it dry for some time before planting it, so that the wound can heal. For now I just left it on ...
6
votes
4answers
357 views

Identity and give care instructions for mammillaria cactus

Hi, I think I just bought a mammillaria cactus. What is the subspecies and how do I care for it best? What colour flowers to expect? What should I do with the fruits sticking out (propagation ...
6
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1answer
2k views

What type of soil do cacti prefer? (acidic or alkaline)

I have done some research and found some sites suggesting alkaline soil while others say that alkaline soil will inhibit the growth of a cactus.
6
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1answer
311 views

What is this flowering succulent?

I just moved into this house and there are a few random potted plants left over from the previous tenants. I live in Perth, Western Australia. I recently gave this one some water since it didn't look ...
6
votes
2answers
748 views

What is this succulent with flat hairy leaves?

This succulent is about 1.5 feet tall. The leaves are flat with a white hairy type substance. What is it called?
6
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1answer
2k views

Can we root prickly pear pads that are sold in grocery stores as a vegetable?

Can I root prickly pear pads that I buy (presumably for food) in the grocery store? It seems like it would be a great way to get some thornless prickly pear cacti growing. If I were to do it, I would ...
6
votes
1answer
177 views

How should I cut a long, curvy cactus?

I have received a cactus that is a bit curvy. Here's some pictures to give you an idea: It's doing well right now but I'm concerned that the curve will eventually break it. Is it possible to cut this ...
6
votes
1answer
2k views

White spots at the base of a cactus

Somebody gave me this cactus and I noticed that the base is getting white. Is it normal? Other information: I live in Canada The cactus is indoor and facing the sun all day I used soil for cactus ...
6
votes
3answers
611 views

How long can plants survive without light?

For context I'm moving house and shipping most of my stuff. Shipping is expected to take 1-2 weeks. I want to know if shipping my house plants is worth considering. I have a bunch of cacti and ...
6
votes
1answer
1k views

What is this cactus with flat pads and spines growing in small patches?

I was given a cutting of a friend's cactus. It is growing in his front yard but he does not know much about it. His cacti are green and segmented some with red bulbs on top. I believe the red bulbs ...
6
votes
1answer
1k views

My cactus is turning brown on top. Is this usual?

I've just bought this cactus and it's turning brown. I'm wondering if it's because I watered it too much or because of the changing weather? (We rarely have cold days here and it's started to get cold ...
6
votes
1answer
647 views

How do I safely eradicate mold without hurting cactus seedlings?

Here are some of my seedlings, sown a little bit less than a month ago. As you can see, there's mold starting to form. I am using the baggie method whereby the pot with the seeds is enclosed in a ...
6
votes
1answer
1k views

Problems with fairy castles cactus

My beloved fairy castles cactus has been suffering for a while and I was wondering what could be happening now. It looks like having several different problems... specially worried as it looks ...
6
votes
1answer
82 views

Will repotting a cactus after flowering affect the fruit?

It is generally advised against repotting a cactus while it has buds or flowers on it. My Mammillaria prolifera has just finished flowering and it really needs repotting but since it's a self-fertile ...
5
votes
4answers
17k views

How to fix a broken cactus

I have been growing this guy for 6 years. He's gotten a little too top heavy and today has fallen over and the top piece (about 9") broke off. The break was very even. I have no idea where to begin ...
5
votes
3answers
3k views

Why is my cactus so thin?

About one year ago, I purchased three cacti in the same pot. They looked like this when I got them: One of them got bigger over the months, but the tallest one kept thinning. As you can see from the ...
5
votes
2answers
423 views

Will prickly pear thrive under the eaves on the west side of my house?

The front of my house faces due west, with about a 2' overhang underneath the eaves. There is a 12' section between the northwest corner and the walkway leading to my door that has proven very ...