Watering Japanese maples

The principle

A Japanese maple (Acer palmatum) likes a fresh root environment, but it hates suffocated roots. So the rhythm is always the same: water thoroughly, then let the substrate breathe before watering again.

It’s not “a little bit every day”. It’s “properly, then wait”.

Watering in a container

How to water correctly

Water until it runs freely from the drainage holes underneath. The goal is to wet the entire rootball, not just the surface.

Then wait until the substrate starts to dry at the top before watering again (not “out of habit”).

When to water

A simple indicator:

  • touch the substrate 2–3 cm down: if it’s still clearly moist, wait,
  • if it’s dry on the surface but still cool underneath, you can water moderately,
  • if it’s dry deeper down, water thoroughly.
What makes the biggest difference in a pot
  • Wind + sun = the pot dries quickly, even if temperatures are not extreme.
  • Pot size : a larger pot stabilizes watering (fewer sudden swings).
  • Substrate : if it’s too fine/compact, you can water “correctly” and still run into issues (lack of air).
Common mistakes
  • watering a small glass every day (the rootball never gets properly soaked; roots stay near the surface),
  • leaving water in a saucer (especially in cool periods),
  • spraying the foliage in full sun (unnecessary, sometimes counterproductive).

Watering in the ground

The right method

In the ground, you water less often, but more deeply. A good watering should moisten the root zone, not just the crust on top.

When to water

Best test: scratch the soil 8–10 cm down:

  • if it’s still cool/fresh, wait,
  • if it’s dry at that depth, water.
A small “premium” detail: mulching

A clean mulch greatly stabilizes moisture: fewer peaks, less stress, fewer “marked” leaves.

Adjusting by season

  • Spring : needs are often moderate; watch for sudden swings (pots that dry fast in wind).
  • Summer : watering becomes more frequent; ideally in the morning during hot periods.
  • Autumn : gradually space watering out.
  • Winter : use common sense (in a pot: avoid a completely dry rootball, but above all avoid standing water).

FAQ

How often should I water a potted Japanese maple?
When the substrate starts to dry at the surface: water thoroughly, then let it breathe.

Should I water a Japanese maple every day?
Generally no. It’s better to water properly and then wait, rather than small daily top-ups.

How can I tell if my maple is thirsty?
In a pot: finger test 2–3 cm down. In the ground: check at 8–10 cm. Water when it’s dry at that depth.

Why do leaf edges turn brown?
Often drying wind + sun + irregular watering (especially in containers). It’s not automatically a disease.

Can I water with tap water?
Yes in most cases. If your water is very hard and you grow in pots long-term, rainwater can be a plus.