Watering and seasonsBC-05
How Often to Water Bonsai: Seasonal Guide for 13 Species, plus Summer Evenings, Winter, Trips and Drying Out
For most outdoor species, water bonsai 1 to 2 times a day in spring and 2 to 3 times a day in summer. Adjust by how the soil dries.
In this article (15 sections)
- In short: how often do you water bonsai in each season?
- How often to water bonsai: how do the 13 species compare by season?
- How often to water bonsai: why do sources differ?
- How often to water bonsai: how do pot size, soil and placement change it?
- How much and when should you water bonsai?
- What tools do you need for watering bonsai?
- Should you water bonsai in the morning or evening in summer?
- How often should you water bonsai in winter?
- How do you water bonsai while you travel?
- How do you tell drying out from root rot?
- How often to water bonsai: which species need extra care?
- What terms come up in bonsai watering?
- What else goes with bonsai watering?
What are common questions about how often to water bonsai?5
- Sources
In short: how often do you water bonsai in each season?
For most outdoor species, how often to water bonsai is 1 to 2 times a day in spring and 2 to 3 times a day in summer. In winter, cut back in line with dormancy, to once every 1 to 4 days.
The usual approach to bonsai watering is to water when the soil surface is starting to dry. Garden center guides also give once a day in spring and autumn as a guide.
But even in the same season, how often changes with the species and the size of the pot. This site has put seasonal guides for 13 species into one table.
What this article covers:
- Watering guides for spring, summer, autumn and winter for 13 species
- How to change the frequency for pot size, soil and placement
- How much to give each time, and how to use morning and evening in summer
- Winter watering, and tips for when you travel
- How to tell drying out from root rot, and what to do
Choose a month and a species in the tool above to see the seasonal watering guide along with that month's jobs. The season switches every 3 months.
For how often to water bonsai, start from the guide in the table and adjust by how the soil dries.
How often to water bonsai: how do the 13 species compare by season?
| Species | Type | Spring | Summer | Autumn | Winter |
|---|---|---|---|---|---|
| Japanese black pine | Conifer | Twice a day (morning and evening) | 2-3 times a day | Twice a day (morning and evening) | No source |
| Japanese white pine | Conifer | About once a day, after it dries | 1-2 times a day | About once a day, after it dries | Every 3-4 days (in a cold frame) |
| Shimpaku juniper | Conifer | Twice a day | 2-3 times a day | Twice a day | Every 2-3 days (in a cold frame) |
| Needle juniper | Conifer | 1-2 times a day | 2-3 times a day | 1-2 times a day | Every 2 days |
| Japanese maple | Deciduous | Twice a day | 2-3 times a day | No source | Every 1-2 days |
| Trident maple | Deciduous | 1-2 times a day | 2-3 times a day | No source | Every 2-3 days (in a cold frame) |
| Japanese zelkova | Deciduous | 1-2 times a day | 2-3 times a day | No source | Every 1-2 days |
| Japanese apricot (ume) | Flowering | 1-2 times a day | 2-3 times a day | 1-2 times a day | Every 2-3 days (in a cold frame) |
| Flowering cherry (e.g. Asahiyama) | Flowering | Twice a day | 2-3 times a day or more | Twice a day | Every 2-3 days (in a cold frame) |
| Satsuki azalea | Flowering | 1-2 times a day | 2-3 times a day (not in the midday heat) | 1-2 times a day | Every 2-3 days |
| Chojubai (dwarf flowering quince) | Flowering | 1-2 times a day | 2-3 times a day | No source | Every 2-3 days (in a cold frame) |
| Crabapple (hime-ringo) | Fruiting | 1-2 times a day | 2-3 times a day | No source | Every 2-3 days |
| Banyan fig (gajumaru) | Indoor | Water well when the surface dries | When the surface dries, in the early morning or evening | Water well when the surface dries | Less often, only after the soil dries well |
The values in the table are guides taken, species by species, from bonsai writers and garden product makers. Where no source gives a value, the cell says "No source"; nothing has been filled in by guesswork.
The table shows 4 things.
- In summer, 11 of the 12 outdoor species are 2 to 3 times a day (cherry says "or more")
- Japanese white pine is lower than the other conifers in every season
- Every species that has an autumn guide has the same frequency as in spring
- In winter, watering continues even for species kept in a cold frame
For outdoor species, the rough pattern is 2 to 3 times a day in summer and once every few days in winter. The timing of jobs for each species is in How to Care for Bonsai and the Yearly Calendar.
How often to water bonsai: why do sources differ?
Because each source assumes a different pot, spot and way of dividing the seasons. Use the numbers as a starting point and decide by how the soil dries.
| Source | Spring | Summer | Autumn | Winter |
|---|---|---|---|---|
| Omiya Bonsai Art Museum | Not stated | 3 or more times a day | Not stated | About once a day |
| All About (Seikoen) | 1 to 2 times a day | Twice a day | 1 to 2 times a day | Every 2 to 3 days |
| Komeri | Once every day | Adjust to conditions | Once every day | Adjust to conditions |
For winter, the museum says about once a day, and the Seikoen guide every 2 to 3 days. Both are bonsai specialists in Saitama, yet the range is this wide.
The Omiya Bonsai Art Museum gives these reasons for changing the amount and timing of water.
- Season and weather
- Whether the tree is deciduous or evergreen, and its species
- The age of the tree, and the years since repotting
- The shape of the pot
The numbers in the sources are a starting point; adjust them to your own pot and spot. How the table values were chosen is in How this site sets the timing.
How often to water bonsai: how do pot size, soil and placement change it?
Small pots and spots with strong sun and wind dry out faster, so water more often. Look at the soil surface and decide by how dry it is.
| Condition | What happens | How to change watering | Source |
|---|---|---|---|
| Small pots and mini bonsai | Little soil, so it dries fast | In hot weather, check for dryness in the evening too | Hyponex |
| Shallow, flat pots | Roots fill the whole pot, and water struggles to soak in deep | Water once, wait a while, then water again | Omiya Bonsai Art Museum |
| Spots with strong sun or wind | Dries fast | Water more often than the seasonal guide | All About (Seikoen) |
| Pots with hardened soil | Water struggles to soak in | Gently submerge the whole pot in water | All About (Seikoen) |
| Right after repotting | The roots cannot take up enough water | Water the leaves too, and do not let the soil dry out completely | Omiya Bonsai Art Museum |
| Set directly on a floor or balcony | Reflected heat makes the pot hot | Put it on a stand and leave space between pots | Hyponex |
You can tell how dry the soil is from the color of the surface. In the KINCHO Engei guide, dark and moist soil needs no water. Whitish, dry soil means it is time to water.
You can also lift the pot and check dryness by its weight. Hyponex also recommends checking the pot's weight and the leaves in the evening.
If in doubt, touch the soil surface with your finger. If it feels moist, it is fine to skip that watering.
What sets the frequency is not the calendar but how the soil in front of you is drying. Care right after repotting is also covered in When to Repot Bonsai.
How much and when should you water bonsai?
Water bonsai until water runs out of the drainage hole. Water when the soil surface is starting to dry.
The Seikoen guide sums up the basics of watering as "when you water, water plenty." Even if the soil is only a little dry, give plenty when you water.
- Look at the soil surface and check that it is starting to dry
- Bring the spout of the watering can close to the base, and pour around it, following the shape of the pot
- Keep going until water runs out of the drainage hole
- For shallow pots, wait a little and water once more (a second pass)
- Empty any water left in the saucer
If you pour it all in one spot, the water tends to run out of the pot before it soaks into the soil. The Seikoen guide calls water poured around the base "root water" (nemizu).
The water in the saucer is emptied because roots can rot if the bottom of the pot stays wet for a long time.
Think of the amount as "until it runs from the bottom," and the frequency as "when it starts to dry."
What tools do you need for watering bonsai?
You can start watering bonsai with just a watering can that pours gently at the base. A container you can submerge a whole pot in is also handy for pots with hardened soil.
| Tool | When to use it | Source |
|---|---|---|
| Watering can | Bring the spout close to the base and pour around it, following the shape of the pot | All About (Seikoen) |
| Watering jug, or a watering can with the rose removed | Pour gently at the base of the plant, in several goes | KINCHO Engei |
| Container of water | Submerge a whole pot that water will not soak into | All About (Seikoen) |
| Automatic watering device | When you are away for more than 5 days | All About (Seikoen) |
| Pot stand | Keeps the pot away from heat reflected off the floor | Hyponex |
The KINCHO Engei guide recommends pouring in several goes so the whole surface gets moist. Pouring hard can wash soil away or let water escape out of the pot.
Keeping the watering tools right next to where the trees sit makes it easier to keep up morning and evening watering in summer.
You need few tools; what matters most is being able to pour gently at the base.
Should you water bonsai in the morning or evening in summer?
In summer, make the cool morning the base for watering bonsai. Small pots that dry fast also get water in the evening.
Hyponex writes to avoid watering in the hot part of the day. The water in the pot can heat up and put stress on the roots.
| Time | What to do | Why |
|---|---|---|
| Morning | Give the day's main water, plenty of it | It is cool, and it prepares the tree for drying during the day |
| Hot part of the day | Avoid it at home | The water in the pot heats up and stresses the roots |
| Evening | Water dry pots, and spray the whole tree | Small pots dry out by evening. It makes up for dry leaves |
On the other hand, the Omiya Bonsai Art Museum waters 3 or more times a day in summer: morning, midday and evening. It says the timing is decided by the gardeners' experience.
At home, making morning the base and topping up after checking for dryness in the evening is easier to manage.
Evening leaf watering means spraying the whole tree to give the leaves moisture. The Seikoen guide says it also helps prevent spider mites.
We did not find any source this time that recommends watering late at night. The times the sources give are morning and evening.
In summer, combine shade with watering. Japanese maple, trident maple, cherry and others are shaded in summer. Shimpaku gets no shade even in midsummer.
Make summer morning watering a habit before you go out, and you will not forget it. In the evening, lift the pot, and if it feels light, top it up.
In summer, morning as the base and topping up only dry pots in the evening helps prevent both overwatering and drying out.
How often should you water bonsai in winter?
Water bonsai less often in winter, in line with dormancy. For the outdoor species in this table, the guide is once every 1 to 4 days.
The winter guide varies by species. Japanese white pine in a cold frame is every 3 to 4 days, and maple and zelkova every 1 to 2 days.
Even in winter, the tree uses water. The Omiya Bonsai Art Museum says conifers such as shimpaku give off water from their leaves in winter too.
The winter spot differs by species. A different spot also changes how fast the soil dries, so check the two together.
| Species | Winter spot |
|---|---|
| Japanese black pine | Outdoors on the bench, out of drying wind; small or weak trees under eaves or in a cold frame |
| Japanese white pine | Cold frame (mid-December to February) |
| Shimpaku juniper | Under the bench or in a cold frame after 2-3 frosts |
| Needle juniper | Cold frame, moved in early (weak to cold and dry air) |
| Japanese maple | Cold frame after 2-3 frosts |
| Trident maple | Under the bench or in a cold frame after 2-3 frosts (mid-December to March) |
| Japanese zelkova | Under the bench or in a cold frame after 2-3 frosts |
| Japanese apricot (ume) | Cold frame |
| Flowering cherry (e.g. Asahiyama) | Under the bench or in a cold frame after 2-3 frosts |
| Satsuki azalea | Under the eaves (December to March) |
| Chojubai (dwarf flowering quince) | Cold frame |
| Crabapple (hime-ringo) | Cold frame, out of frost and dry winter wind |
| Banyan fig (gajumaru) | Indoors (5°C or above) |
Source (13)
- Omiya Bonsai Art Museum newsletter Vol.55 (candle cutting Jun–Jul), Kimi's Mini Bonsai Days, Komeri, e-Bonsai
- Kimi's Mini Bonsai Days, Komeri, e-Bonsai, Omiya Bonsai Art Museum newsletter Vol.50
- Kimi's Mini Bonsai Days: Shimpaku juniper
- Kimi's Mini Bonsai Days (needle juniper), e-Bonsai (repotting)
- Kimi's Mini Bonsai Days (Japanese maple), e-Bonsai (repotting), Saitama City reports on the museum collection
- Kimi's Mini Bonsai Days (trident maple), e-Bonsai (repotting)
- Kimi's Mini Bonsai Days (zelkova), e-Bonsai (repotting)
- Kimi's Mini Bonsai Days (ume), All About (Kaori Yamada, Seikoen), e-Bonsai (repotting)
- Kimi's Mini Bonsai Days (cherry), e-Bonsai (repotting)
- Kimi's Mini Bonsai Days: Satsuki azalea
- Kimi's Mini Bonsai Days (chojubai), e-Bonsai (repotting)
- Kimi's Mini Bonsai Days (crabapple), e-Bonsai (repotting)
- Hyponex Plantia: How to grow gajumaru
A cold frame or the space under the eaves gets no rain, so it is easier to forget watering there than on an outdoor bench.
Gajumaru spends the winter indoors. Water it less often, and only after the soil has dried well.
Even when you water less in winter, do not stop watering altogether. Ways to protect trees from the cold are covered in Bonsai Winter Care.
How do you water bonsai while you travel?
For trips of up to about 5 days, wrap the pot in a wet towel and a plastic bag before you leave. For longer trips, use an automatic watering device.
| Time away | Method | What to watch |
|---|---|---|
| Up to about 5 days | Water plenty on the morning you leave. Wrap the pot in a wet towel and cover it with a plastic bag | Keep the leaves outside the bag, and bring the tree indoors before you leave |
| More than 5 days | Use an automatic watering device | Run it before you leave and check that the water reaches the pot |
| Long trips in summer | Ask family or a friend to water | Write down the seasonal frequency guide and hand it over |
This wrapping is a simple trick for time away, introduced in the Seikoen guide.
When you get back, first look at how dry the soil is and how the leaves look. If they are wilting, go to the fixes for drying out below.
Think of short trips as wrapping to keep moisture in, and long trips as a device or a helper.
How do you tell drying out from root rot?
Both make the leaves wilt, but if the soil is dry suspect drying out, and if it stays wet suspect root rot. First, check the soil with your finger.
| What to look at | Drying out | Root rot |
|---|---|---|
| Soil surface | Whitish and bone dry | Does not dry; stays wet |
| Leaves | Wilt and droop | Look weak, turn yellow and drop |
| Why it happens | No water until the soil was bone dry | Watering went on while the soil was not dry |
| First fix | Water until it runs from the bottom of the pot | Empty the saucer and wait until the soil dries |
There are other signs of root rot too. A garden product maker's guide to potted plants lists a rotten smell from the soil and black roots.
After drying out, treat the tree in this order.
- Water until it runs from the bottom of the pot
- If water will not soak in, gently submerge the whole pot in water
- Move it to bright shade, and do not feed or repot
- Hold off on heavy pruning until new buds appear
If you suspect root rot, hold back water and let the soil dry. Put the tree in a bright spot with good airflow, and check the roots at the right time for repotting.
Japanese white pine is a tree whose roots are easily damaged by overwatering. In the table too, its guide is lower than the other conifers.
When you see wilted leaves, touch the soil with your finger before watering. If it is wet, water will only make things worse.
When a tree wilts, touch the soil before you water. This alone helps prevent the mistake of making root rot worse.
How often to water bonsai: which species need extra care?
Among the 13 species, Japanese white pine, shimpaku, Japanese maple, ume, cherry, satsuki and gajumaru have notes that differ from the others.
| Species | Note | Source |
|---|---|---|
| Japanese white pine | Roots are easily damaged by overwatering. A tree of high mountains, so its guide is lower | Kimi's Mini Bonsai Days, Omiya Bonsai Art Museum |
| Shimpaku juniper | Gives off water from its leaves in winter too, so do not let it go dry in winter | Omiya Bonsai Art Museum |
| Japanese maple | Draws up large amounts of water in the growing season | Omiya Bonsai Art Museum |
| Japanese apricot (ume) | Its flower buds start moving earlier than other deciduous trees, so change the amount and timing of water | Omiya Bonsai Art Museum |
| Flowering cherry (e.g. Asahiyama) | High in summer, at 2 to 3 times a day or more | Kimi's Mini Bonsai Days |
| Satsuki azalea | In summer, avoid watering in the midday heat | Kimi's Mini Bonsai Days |
| Banyan fig (gajumaru) | Indoors, once the surface dries. Less often in winter | Hyponex |
Even at the same "twice a day," species use water differently. The museum says broadleaf trees such as maple and conifers such as shimpaku adjust to the seasons in different ways.
Read the species notes together with the frequency in the table. The year's jobs for each species are in the calendar in How to Care for Bonsai and the Yearly Calendar.
What terms come up in bonsai watering?
| Term | Meaning |
|---|---|
| Root water (nemizu) | Water poured around the base, following the shape of the pot |
| Leaf watering (hamizu) | Spraying the whole tree or the leaves to give the leaves moisture |
| Second pass (kaeshimizu) | Watering once, waiting a while, then watering again |
| Submerging (dobuzuke) | Gently submerging the whole pot in a container of water |
| Drying out | The soil dries out completely and the tree wilts |
| Root rot | The soil stays wet, and the roots are damaged and rot |
| Cold frame | An enclosure or shed that protects bonsai from cold and drying wind in winter |
| Dormancy | Stopping growth in winter to get through the cold |
What else goes with bonsai watering?
Bonsai watering is linked to placement and to the seasonal jobs. Start with whatever you are curious about.
- Yearly jobs for 13 species: How to Care for Bonsai and the Yearly Calendar
- Care right after repotting: When to Repot Bonsai
- The winter spot and cold protection: Bonsai Winter Care
- When to feed: When to Fertilize Bonsai
Year calendarHow to Care for Bonsai: A Yearly Calendar for 13 Species, Seasonal Care, and 3 Basics for BeginnersHow to care for bonsai with a yearly calendar for 13 species, from black pine to maple and satsuki. Repotting, pruning and feeding by group, and fixes.
When to do itWhen to Repot Bonsai: Months for 13 Species, How Often, Rootbound Signs and AftercareWhen to repot bonsai, by month for 13 species. Spring before bud break is the rule. Exceptions, how often, rootbound signs, steps and aftercare, with sources.
Watering and seasonsBonsai Winter Care: Where to Keep 13 Species, Why Frost Comes First, Cold Frame Alternatives, Winter Watering and Checking for Dead TreesBonsai winter care: winter spots for 13 species, why trees take 2 to 3 frosts first, cold frame or under the bench, winter watering and spotting dead trees.
When to do itWhen to Fertilize Bonsai: Months for 12 Species, Why Stop in Midsummer and Winter, Solid vs Liquid, and Fertilizer BurnWhen to fertilize bonsai, by month for each species. Feed in spring and autumn, stop in midsummer and winter. After repotting, solid vs liquid, fertilizer burn.What are common questions about how often to water bonsai?
Do bonsai need watering every day?
For outdoor species, almost every day from spring to autumn. In winter, cut back in line with dormancy, to once every 1 to 4 days.
Decide by whether the soil is starting to dry, not by a daily count.
How many times a day should you water bonsai in summer?
For the outdoor species in this table, most are 2 to 3 times a day. Japanese white pine is lower, at 1 to 2 times a day.
For small pots, check for dryness in the evening too.
Can you water bonsai at night?
The times the sources give are morning and evening, and we found no source that recommends late at night. In summer, top up dry pots while it is still evening.
Give the main water in the cool morning.
What do you do when you go away on a trip?
For up to about 5 days, wrap the pot in a wet towel and a plastic bag, put it indoors, and then go. For longer trips, use an automatic watering device.
Keep the leaves outside the bag.
How much water should you give bonsai?
Until water runs out of the drainage hole. For shallow pots, watering once more after a while gets the water all the way down.
Empty the water left in the saucer every time.
Sources
- Omiya Bonsai Art Museum, Saitama City: Jinshari newsletter Vol.46 "Summer work: the secrets of watering" (in Japanese. About once a day in winter, 3 or more times a day in summer, the second pass, leaf watering right after repotting, how each species uses water)
- All About: "Watering bonsai" by Kaori Yamada, Seikoen (in Japanese. Frequency by season, root water, submerging, evening leaf watering, tips for time away)
- Komeri HowTo: "Bonsai (care)" (in Japanese. Once a day in spring and autumn, adjust in summer and winter)
- Hyponex: "Heat protection for planters and potted plants, and how to revive weakened plants" (in Japanese. Morning is the base in summer, small pots in the evening too, check the pot's weight, do not set pots directly on the floor)
- Hyponex: "How to grow pachypodium" (in Japanese. Signs of root rot: the soil does not dry, a rotten smell, black roots)
- Hyponex Plantia: "How to grow gajumaru" (in Japanese. Watering by season)
- KINCHO Engei: "How do you keep plants comfortable?" (in Japanese. Judging dryness by soil color, water in the saucer, drying out and root rot)
- Kimi's Mini Bonsai Days: "How to grow bonsai" (in Japanese. Seasonal watering guides for 12 species)