Bonsai care calendar

Bonsai care is a calendar, not a checklist. Almost every job on a tree — repotting, feeding, the shaping cuts, getting it through winter — belongs to a season, and doing the right thing in the wrong month is how beginners lose trees. This works out what your tree needs in the month you pick, and when its next repotting window opens. It won’t tell you when to water: that one is never on a calendar.

Which kind of tree is it?
Where does it live?
Which month, and which half of the world?
How far along is the tree?
When did you last repot it?

After the month’s jobs

The calendar knows the month. Bonsai keeps what this tree did in it.

  1. The calendar gives you this month’s jobs. Repot, feed, cut back or protect — and when the next repotting window opens.
  2. Do the job, then log it on the tree. Watering, pruning, repotting, fertilizing and wiring all go on the same tree’s page, with the date.
  3. Next year, the window opens with a history. The tree’s page shows when it was last repotted, so you’re not guessing whether it’s due.
Bonsai Add Bonsai form with species, stage, tree style, adopted date and sunlight fields
Species in, onceThe facts this calendar asked for, saved on the tree.
Bonsai tree page for a Satsuki azalea showing species, pot size, soil mix, last watered and last repotted
Last repotted: on the pageThe date the next repotting window is counted from.
Bonsai trends screen counting care events by week, month and year
A year of care, countedWeek, month or year — which jobs actually got done.
Get Bonsai on the App Store → Free to download · iPhone · no account, stays on your device

Why a calendar, when watering isn’t on one

Those two rules look contradictory and aren’t. Watering answers to the weather, which changes hour to hour, so a fixed watering day is guaranteed to be wrong most weeks — you check the soil and let it decide. Everything else answers to the tree’s own year, which is slow and predictable: roots are disturbed while the tree is about to push growth, feeding follows the growing season, hard cuts wait for the right window, and a hardy tree needs its cold months. That part genuinely is a calendar, and it’s the part beginners are usually never told.

Repotting is the clearest case. It is not a response to a tree looking pot-bound in August — it’s an early-spring job, and this tool will never say “repot now” in any other month, however overdue the tree is. Waiting until spring is the correct answer even when the answer is annoying.

Where this comes from

The month’s jobs are the seasonal table in our own guide, how to care for a bonsai tree: spring for repotting, fresh growth, the first feed and structural work; summer for frequent watering, maintenance pruning and pinching; autumn to ease off feeding and prepare hardy trees for winter; winter for dormancy, minimal water and cold protection. The indoor-versus-outdoor split is the same guide’s rule that tropical species can live indoors by a bright window while temperate species must stay outside year-round.

The repotting cadence is the guide’s 2–3 years for most young trees, less for older ones. Because it names no number for older trees, neither does this — that answer comes back as “keep your own record” rather than an invented interval. Two things here are our estimate, not the guide’s: which calendar months map to which season, and that early spring means March in the northern hemisphere and September in the southern. Your local spring may run a few weeks either side, and the tree is the better signal than the date.

If you’re not sure, do less

The errors in bonsai care are not symmetrical. Skipping a feed costs the tree a little growth you’ll get back next season. Repotting in the wrong month, cutting a branch you can’t put back, or bringing an outdoor tree in to “protect” it from a winter it needs — those can cost the tree. So where this tool is uncertain it points at waiting and recording rather than acting, and the beginner version of every shaping job is the light version.