Gadenin日本語Get the appWhen it actually needs it
A young coffee plant grows fast enough to need a new pot every year for the first three or four years. After that, every two or three years is plenty, and a mature plant in a large pot can go longer still if you top-dress instead. Repotting on a calendar rather than on evidence is a common way to set a plant back, because coffee grows better slightly snug than swimming in fresh compost.
Do it in spring, as the days lengthen and you see the first new pair of leaves opening. A plant repotted then has the whole growing season to put roots into the new compost. Repotting in autumn or winter leaves cold wet compost sitting around damaged roots for months, and that is where rot begins.
| Sign | What it means | Action |
|---|---|---|
| Roots coming out of the drainage holes | The root ball has filled the pot | Repot next spring, one size up |
| Water runs straight through in seconds | Almost all root, very little compost left | Repot as soon as spring arrives |
| Drying out every two days in summer | Root bound | Repot, or move to a shadier spot until spring |
| White crust on the compost surface | Fertilizer salts have built up | Top-dress or repot into fresh mix |
| Growth has stalled but roots look fine | Usually light or feeding, not the pot | Do not repot. Fix the position first |
One size up, and never more
Move to a pot one to two inches (3 to 5 cm) wider than the old one and no bigger. In an oversized pot, the compost out beyond the roots holds water that nothing is drinking, stays wet for weeks and rots the root ball from the outside in. This is the single most damaging repotting mistake with coffee, and it usually happens with good intentions, from wanting to save doing it again next year.
Drainage holes are not optional. Coffee will not tolerate a sealed decorative pot, so if you want one, use it as a cachepot with the plastic nursery pot standing inside and lift the inner pot out to water. Terracotta suits coffee well because it breathes and dries evenly, at the cost of needing water rather more often.
The compost it wants
Coffee is an acid-loving plant that grows naturally in loose forest soil full of leaf litter. It wants a mix around pH 6.0 to 6.5, holding moisture but draining fast, and open enough that air reaches the roots. Ordinary all-purpose potting mix on its own packs down within a year and holds too much water, which is why a plant that was fine in its first season starts yellowing in its second.
A mix that works is roughly two parts peat-free multipurpose or a coir-based mix, one part fine bark or perlite for air, and a handful of composted bark or leaf mold for acidity and structure. An acidic potting mix is a good base if you have it. Do not add lime or use a mix that includes it.
| Component | Proportion | What it does |
|---|---|---|
| Peat-free or coir-based potting mix | Two parts | Holds moisture and nutrients |
| Perlite or fine bark | One part | Air space and drainage |
| Composted bark or leaf mold | A generous handful | Acidity and open structure |
| Slow-release feed | As directed on the pack | Optional. Skip it if you feed liquid in summer |
No crocks or gravel in the bottom of the pot. A drainage layer does not help and actually raises the wet zone in the compost above it. Put mix all the way down and make sure the holes stay clear.
Doing it without breaking the roots
Coffee roots are brittle, and a seed-grown plant keeps a taproot that dislikes being handled. The aim is to move the root ball intact into more compost, not to comb it out the way you would with a pot-bound fern.
- Water the day before A moist root ball holds together and slides out. A dry one crumbles and takes roots with it. Do not repot a plant that has just been drenched either, because sodden compost is heavy and smears.
- Ease it out sideways Lay the pot on its side, press round the sides to release it, and slide the plant out with a hand supporting the base of the stem. Never pull on the trunk to lift a stuck plant. If it will not come, run a knife round the inside of the pot.
- Loosen, do not tease If roots are circling the outside, gently free just those and cut through any that have wound right round the base. Leave the middle of the root ball completely alone. Cut off any black, soft or hollow roots you find.
- Keep it at the same depth Put enough mix in the bottom that the old compost surface sits about an inch (2 cm) below the rim, exactly as deep as before. Burying the stem deeper causes rot at the collar.
- Fill and settle without ramming Work fresh mix down the sides with your fingers or a stick, tapping the pot on the bench to settle it. Firm gently. Compost packed down hard drives the air out, which is the thing coffee minds most.
- Water once, then hold back Water thoroughly to settle the mix and drain it well. Then keep it out of direct light for one to two weeks, water sparingly, and do not feed for four to six weeks while the damaged root tips heal. Some leaf droop in the first week is normal.
Note the date, the pot size you moved up to and the mix you used. In two years you will want to know whether the last pot lasted well and whether you are watering more often than you were, and neither is something you will remember.
Top-dressing when the plant is too big to move
A mature coffee plant in a large heavy pot does not have to be repotted forever. Once a year in spring, scrape off the top two inches (5 cm) of old compost, taking care not to tear roots, and replace it with fresh mix. That renews the nutrients and gets rid of the salt crust at the surface without disturbing the root ball at all.
Combine that with a proper leaching once or twice a year: stand the pot somewhere it can drain freely and run water slowly through it for several minutes, several times the pot's volume in total. That washes out accumulated fertilizer salts, which are a common hidden cause of brown leaf edges on a plant that is otherwise being watered correctly.