Gadenin日本語Get the appThe default answer is to leave it alone
Most houseplants respond to a bigger pot by growing faster. A kentia responds by sitting still for a year while it rebuilds the fine roots you tore. Its root system is thick, brittle and slow to regenerate, and every broken root is one the plant must replace out of reserves that a slow grower does not have to spare. This is the single most common way a healthy, expensive kentia is set back.
It also does its best growing when slightly pot-bound. The dense root ball keeps the compost draining fast, which is exactly what this palm wants. A large pot around a small root ball holds a reservoir of wet compost that the roots cannot reach into or dry out, and that is how a repot turns into root rot two months later.
A kentia can stay in the same pot for four or five years and be perfectly healthy the whole time. Roots showing at the drainage holes are not on their own a reason to repot.
When repotting is actually needed
Repot only when you can point to a real problem that a new pot solves. Work down this list before you buy a bigger container.
| Situation | Repot? | Better action |
|---|---|---|
| Roots visible at the drainage holes | No | Normal for this palm, leave it |
| Water runs straight through in seconds | Yes | Root ball is solid, go up one size |
| Pot tips over under the weight of the crown | Yes | Move to a heavier, slightly wider pot |
| Compost stays wet for weeks, sour smell | Yes, urgently | Root rot, refresh into gritty mix |
| White crust on the compost surface | No | Scrape it off, flush the pot |
| Compost is three years old but draining fine | No | Top-dress the top two inches (5 cm) |
| Plant has stopped producing new fronds | Not yet | Check light and watering first |
How to do it with the least damage
Do it in spring or early summer, when the plant has the longest stretch of warm bright weather ahead to rebuild roots. Never repot in autumn or winter. Water thoroughly two days beforehand so the root ball holds together and the roots are turgid rather than brittle.
- Go up only one pot size One or two inches (3 to 5 cm) more in diameter, no more. A deep pot suits the root system better than a wide shallow one. It must have generous drainage holes.
- Slide it out, do not pull the stems Lay the plant on its side, squeeze or run a knife around a rigid pot, and ease the root ball out. Never lift a kentia by its stems, which snap where they meet the root plate.
- Leave the root ball intact Do not tease, comb or wash the roots. Remove only loose surface compost and any roots that are black, hollow or smell sour. Healthy kentia roots are pale and firm.
- Use a fast, open mix Roughly two parts good potting mix to one part coarse perlite or fine bark, plus a handful of coarse grit. It must drain within seconds when you water.
- Plant at exactly the same depth Match the old soil line precisely. Burying the point where the stems meet the roots rots the crown, and planting too high exposes roots that then dry out.
- Water once, then wait Settle it in with one thorough watering, then keep it in moderate light and let the compost dry further than usual for the next month. Do not feed for eight weeks.
Never separate the clump. What looks like one plant with many stems is a group of individual seedlings potted together at the nursery, and splitting them leaves you with several weak plants instead of one full one.
Top-dressing in the years between
Top-dressing gives you most of the benefit of fresh compost with none of the root damage, and it is what you should be doing in four years out of five. Scrape away the top two inches (5 cm) of old compost with your fingers, taking care not to cut roots, and replace it with fresh mix of the same recipe. Do it in spring.
This is also the moment to deal with mineral crust. If the old surface is white or crusted with salts, remove it entirely, then flush the pot: pour water slowly through until roughly four times the pot's volume has drained away, which washes accumulated fertilizer salts out of the root zone. Let it drain fully before it goes back on its saucer.
Record the date, because you will forget
Write down the date of every repot and every top-dress, with the pot diameter you moved to. On a plant repotted once every four or five years, memory is useless, and the note is what tells you whether this year's stall is a plant that needs a pot or a plant that has been in too much shade.
Note the number of fronds at the time as well. If a repotted kentia has not put out at least one new frond within twelve months, it lost more root than it could replace, and you should leave it undisturbed rather than repotting again to fix it.