Questions tagged [cactus]

Member of the family Cactaceae. Desert succulents, but for non-cacti succulents use the [succulents] tag. Use this tag with questions about caring, propagating and identifying cactus.

Cacti are members of the family Cactaceae, and are a distinctive group of plants adapted for low-water and/or hot conditions. Most cacti have evolved so that the stem is succulent and photosynthetic, and the '' have evolved into spines.

Cacti are native to the Americas, with a range extending from Patagonia into southern, central Canada. They are at their most diverse in Mexico and tropical regions of Argentina & Bolivia. Note that this range includes areas that experience hard s - which some varieties tolerate without any problems. They have been introduced into other parts of the world for agriculture.

Cacti tend to have short growing seasons, long periods of dormancy, and large . In the , most grow in mineral rich (humus poor) s that are very free draining. The main exception are the epiphytic cacti which prefer organic-rich soils.

Cacti are usually grown as ornamental plants, mainly , or in xeriscape applications.

They can also be grown for food (e.g. the and pads of are edible when the spines have been removed), and fodder. Many plantations have been developed as a host for cochineal - used to make cochineal dye.

Gardeners are general wary of the spines, but they should also be wary of the hairs which often surround the areoles (spine bases). These are an irritant that are difficult to see when stuck in your skin. Even "spineless" of may have these hairs.

Use this tag for all questions about cacti. Use a specific species tag as well, where appropriate.

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What type of cacti is this?

I would like to know what variety of cactus this is. It has grown three times its height since I bought it and although I have looked on many websites, I just cannot seem to find anything like it.
K. Danko
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What wrong with my cactus

Ive had this cactus which i think is a Pachycereus Schotti/Monstrosus since years and its been growing fabulous. Ive just recently noticed it acquired some brown scales (non Insect) and looks like theres something wrong. Could it be from some…
Desertbum
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Can a cactus be encouraged to "branch out"?

About 5 years ago I was given this cactus, in a minuscule pot and severely dehydrated. To my surprise it responded to watering and repotting really well. About 18 months ago I woke one morning to find it leaned over 90 degrees, bent at the base, the…
Caius Jard
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When and how to repot this cactus?

I found this cactus in a store, it was labeled as "cactus" but I think it is one of the giant cacti (see my previous question). It is about 12 cm in height (without spines). I was wondering when is the best time to repot it into a slightly larger…
benn
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Repot dragon fruit in a definitive pot

I planted these cuttings two months ago and I have a lot of questions. Is it time for repotting? I have 26 liters pots. Is it enough? Can I plant more than one in the same pot? What kind of soil should I use?
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Cactus Identification? Are the buds real?

My friend brought me a little cactus from a plant sale. Unfortunately I don't have a clue about cacti and was wondering if someone could tell me what the little orange buds are? Are they real? I can't see any glue around it but they seem too…
Ash
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Young cactus identification

I bought another small cactus today, the sellers in the store were not sure what species it is. My guess is that it is from the genus Pilocereus, but it is a wild guess. The height is about 7-8 cm (3 inch). Can anyone ID this one with more…
benn
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San Pedro tipped over and broke

My San Pedro has been growing quite a lot the past 2 years, but very thin. It was windy the other day and found him tipped over. Not completely broke in half, only half way. So I tipped him back right side up and have braced him in place. I am…
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Advice on LED light periods for cactus

I want to grow large cacti, see my previous question. So I start with small plants and to keep them growing in winter time I want to give them LED (special grow) light. I was wondering about the best light periods for the small young plants. I am…
benn
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Ants visiting Opuntia

My (elderly) Opuntia gets regular visits from a few ants, which apparently like to draw liquid where its cactus spines emerge. For this relationship between species, do we know whether it is a parasitic or perhaps a symbiotic one?
Drux
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Agave is sweating

It looks as if my agave is "sweating" a crystalline substance. The droplets are approx. 2 mm in diameter and twice as long. Is this as it should be (also the surrounding yellowish patch in the second image) or do I need to contemplate corrective…
Drux
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Various Questions About Fairy Castle Cactus

I have a few questions about my Fairy Castle Cactus. It’s barely grown since I bought it, in contrast to my other plants. I’ve read conflicting info about the amount of light it likes. I’m using the right soil, not overwatering. So, why are the…
CNYC
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Is my cactus dying?

I bought my cactus about one year ago. I was surprised that it grew very fast and I thought it's fine. But it looked too skinny and after some search on the internet I found out it didn't get enough light. I changed its place, now it's near the…
Silvia G.
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Help identify an insect on a cactus

I found this insect on my Echinopsis sp. It sort of looks like a tick, but what would a tick be doing on a cactus? What is it, and is it harmful?
Armen Tsirunyan
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What is wrong with my cactus? (Red spots)

Is it dying? There are these weird red marks, is this a fungal infection or sunburn?