When an offset is ready to remove
An offset (a "pup") is a small clone the parent plant grows at its base or along a stem. The Royal Horticultural Society's general advice is to wait until an offset has reached a decent size before separating it — some pups already carry their own roots by that point and can be potted immediately, while others need to callus first. Removing an offset while it is tiny, or while the parent is not in active growth, gives you a smaller wound to heal and a smaller starting plant with less stored reserve to draw on.
Take offsets during the growing season when you can, so both the parent's wound and the pup's root growth have warmth and light to work with. A plant that is itself stressed, freshly repotted, or in winter rest is a poor candidate to divide.
Clean cuts and disinfected tools
Use pruners, a knife or scissors that are sharp and clean — sharp so the cut is a single decisive slice rather than a crushed, torn edge, and clean so you are not introducing rot organisms into open tissue. Wipe the blade with alcohol between plants, and again between a diseased plant and a healthy one. Wear gloves for anything spined; a crushed grip on a columnar segment is as much a wound as the cut itself.
Cut through firm, healthy tissue in one motion. A ragged or repeated cut leaves more surface area exposed and more places for infection to start.
1Choose the piece
A pup of reasonable size, or a firm stem segment with no soft spots, taken from a plant in active growth.
2Make one clean cut
Sharp, disinfected tool; a single slice through healthy tissue rather than several small cuts.
3Let it callus
Set the cut piece somewhere dry, shaded and airy until the wound has sealed over — a day to a week for many offsets, longer for a thick columnar cut. Let the wound be your guide, not the calendar.
4Set it in barely-moist mix
A well-draining medium, kept just damp rather than wet, until roots take hold.
Why the cut needs to callus first
Callusing means letting the open wound dry until it forms a sealed, corky layer. University of Illinois Extension recommends letting a fresh cutting sit for several days before inserting it into growing medium; RHS puts the same step at anywhere from a day to a week depending on the cutting. The point of the wait is the same either way: a callused surface is far less hospitable to the rot organisms that live in damp soil than an open, wet wound is. Planting a fresh cut straight into moist mix is one of the more common ways a propagation attempt is lost before it starts.
A thin offset from a small globular species may callus in a couple of days. A thick columnar segment, with far more exposed inner tissue, reasonably takes longer — there is no single correct number of days here, and forcing a fixed schedule onto a wound that has not visibly sealed is asking for trouble. If you are unsure whether a plant is rotting rather than healing, see Cactus health.
University of Illinois Extension · Propagating succulents and cacti ↗
Rooting medium and moisture during rooting
Once callused, set the piece on top of or just into a well-draining medium — Iowa State University Extension suggests cactus potting soil cut with perlite; other extension guidance points to a potting mix with added perlite or coarse sand. The shared requirement is a medium that drains fast and does not hold the base of the cutting in standing moisture. Our soil mix guide covers building that kind of blend for established plants; a rooting mix can be a looser, even coarser version of the same idea.
Keep the medium only lightly, consistently damp while roots are forming — RHS describes keeping the compost "only slightly moist" during this stage, and Iowa State's guidance is to keep the surface "damp, but not wet." A cutting does not yet have roots to take up water, so a constantly wet mix mostly just sits against the wound. Small pots or plug trays that dry between light waterings tend to work better than one large, slow-draining container.
Iowa State University Extension · How to propagate succulents ↗
Columnar cuttings vs. globular offsets
The two propagation situations you will meet most often are not quite the same job. Vigorous columnar cacti — the Trichocereus group among them — are usually grown on from stem cuttings: a section of the column, callused and then set upright (or occasionally laid flat to root along more of its length) in a well-draining mix. Because the cut surface is wide, watch it closely through callusing and rooting for any softening rather than assuming it behaves like a small offset.
Small desert globulars more often propagate from offsets that the parent produces on its own — divisions rather than deliberate cuts. Where a plant is reluctant to root from either method, or where you are trying to rescue a stem that has lost its own roots to rot, grafting onto established rootstock is the usual fallback, and it is worth reading before you assume a slow-rooting cutting is a dead one. If you would rather start further back, growing from seed avoids cutting the parent plant at all, at the cost of a much longer timeline to a mature plant.
Rooting signs vs. rot signs
University of Illinois Extension describes a simple check once a cutting has had time to settle in: give it a gentle tug. Resistance means roots have started to anchor it; no resistance means keep waiting. Beyond that, look for the cutting staying firm and its color holding steady, rather than any new growth — new growth at the tip is a later sign, not the first one.
Rot looks different: a soft or mushy patch, a change to a darker, wetter-looking color at or near the cut, or an unpleasant smell. UC IPM lists several rot-causing pathogens that affect cacti through damaged or wet tissue, which is exactly the exposure an uncallused or overwatered cutting invites. A cutting that shrivels slightly while still firm is usually just losing surface moisture and is not automatically failing; a cutting that turns soft is a different, more urgent problem. When you are not sure which you are looking at, Cactus health goes into more detail on distinguishing the two.
What we will not promise
Rooting time is not fixed. University of Illinois Extension puts typical rooting at a few weeks to a month for stem cuttings; Iowa State describes "several weeks" more generally. Species, cutting size, season, temperature and how the cutting was handled before you got it all move that window, sometimes by a lot. A cutting that has not rooted in a month has not necessarily failed, and one that roots in two weeks was not necessarily done well — patience and a tug test tell you more than a countdown does.
This page is a starting point, not a guarantee. Observe your own plant, your own mix and your own conditions, and adjust from there.