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Pachyphytum is not in a hurry. A plant in a suitable pot and a gritty mix is happy for two or three years, and repotting more often than that gains nothing and risks a lot, because every handling costs farina. Repot for a reason, not on a calendar.
The real reasons are these: the compost has broken down and now stays wet for weeks, roots are coming out of the drainage hole in quantity, the plant has grown so much larger than its pot that it topples, or you have unpotted it because something is wrong at the roots. A plant that came home in peat-heavy nursery compost is the other case, and that one is urgent regardless of how long it has been in the pot.
Do it in spring, as growth is starting, or in early autumn once the worst heat has passed. Both give the plant weeks of active growth to put out new roots. Repotting into winter dormancy leaves cut roots sitting in compost the plant cannot use.
| Trigger | Urgency | What to do |
|---|---|---|
| Bought in dark peat-based compost | As soon as the season allows | Bare-root it and repot into gritty mix |
| Compost stays damp for more than three weeks | This season | Repot into a grittier mix, consider a smaller pot |
| Roots out of the drainage hole | This season or next | Move up one pot size only |
| Plant top-heavy and tipping over | When convenient | Heavier pot of similar width, or behead and restart |
| Soft rosette with wet compost | Immediately | Unpot, cut back rotted roots, dry, then repot |
| Plant looks fine, two years in the pot | None | Leave it alone |
Pot and compost
Go up one size and no more, about an inch (2 to 3 cm) wider than the last pot. A plant with those water-filled leaves needs very little root run, and a large pot holds a large volume of compost that the small root system cannot dry out, which is the single most common cause of slow root rot in this genus. Shallow is better than deep for the same reason.
Unglazed terracotta is the easiest choice because it wicks moisture out through the wall and shortens the drying time by days. Glazed ceramic and plastic both work if you make the mix grittier to compensate. A drainage hole is not optional.
The mix should be at least half mineral. A workable recipe is one part standard potting mix to one part pumice, coarse perlite or fine gravel, plus a handful of coarse grit, and in a humid climate push the mineral fraction to two thirds. The test is simple: water it and it should drain almost immediately, and a skewer pushed to the base should come out dry within a week in warm weather.
Skip the layer of gravel or crocks at the bottom of the pot. It does not improve drainage. It raises the level at which water sits and reduces the depth of compost the roots can use, which makes the pot effectively wetter, not drier.
The repotting itself, step by step
Do the whole job with dry compost and a dry plant. Dry compost falls away from the roots instead of clinging, dry roots are less likely to tear, and a dry plant is lighter and easier to hold by the base. Water nothing for a week beforehand.
- Have everything ready before you pick the plant up New pot, mix, a spoon, snips and a soft dry brush laid out. The fewer seconds the plant spends in your hands, the fewer marks it ends up with. Decide where each thing goes before you start.
- Slide it out by squeezing the pot, not by pulling the plant Press the sides of a plastic pot, or tap the rim of a terracotta one against a table edge, and let the root ball slide out into your open palm supporting it from below. Never lift a pachyphytum out by gripping the rosette.
- Crumble the old compost away and look at the roots Work the dry compost off with your fingers and a spoon handle. Healthy roots are pale, firm and stringy. Anything brown, hollow or mushy is dead and should be cut back to firm tissue with clean snips. Look closely for white waxy specks among the roots, which are root mealybugs.
- Hold the plant by the bare stem, not the leaves Grip the woody or semi-woody stem below the lowest leaves between finger and thumb. If there is no bare stem, strip the lowest one or two leaves to make some, and keep those leaves for propagation.
- Set it at the same depth and fill around it Position the plant so the stem base sits where it did before, and spoon the mix in around it, tapping the pot on the bench to settle it. Do not press the compost down with your fingers, which compacts it and puts your hand near the leaves.
- Top-dress with grit and wait a week A layer of coarse grit at the surface keeps the stem base dry and stops compost splashing onto the leaves. Then give no water at all for seven to ten days, so cut roots seal instead of taking up water and rotting.
After it is potted
Keep the plant in bright indirect light for the first week or two rather than full sun. It has a reduced root system and cannot replace water lost through the leaves at the usual rate, so full sun at this stage causes shriveling that is easily mistaken for underwatering and easily made worse by watering.
The first water after repotting should be a full soak that drains freely, and after that you are back on the normal cycle of bone-dry compost between waterings. Do not feed for at least a month. Fresh compost has enough in it, and fertilizer on damaged roots does harm.
Expect a few weeks with no visible growth. New leaves at the center of the rosette are the sign the plant has rooted in, and once they appear you can move it back into full sun.
Write the date on the pot label along with the mix you used and the pot size. When a plant later dries out in five days or still holds water at week four, that label tells you which of your mixes did it, and you can repeat or avoid it deliberately instead of guessing next time.