Repotting advice JWP

[vp999]

Sweet! I am looking for something roughly 18"x15" and around 4-5" deep.

I’ll let u know soon.

 

[snowman04]

How much deeper should the pot be? The current pot is 3.5" tall (externally). This one looks like it is 4.75" tall. Is an inch enough or could I go a bit deeper? What is too deep?

One more inch of depth in an 18" pot is a fair amount of more soil... If you are leaving it in this pot for three more years, ok. Let those roots develop...

 

[NMbonsai]

Good advice from @snowman04. Conifers grow a lot slower than deciduous trees in general, so you won't need to repot your pine for several years. As stated, this will allow more root development to feed the upper growth, which you will be working on to bring the tree into refinement. Nice pot, BTW.

 

[River's Edge]

One more inch of depth in an 18" pot is a fair amount of more soil... If you are leaving it in this pot for three more years, ok. Let those roots develop...

With Pines a well respected guideline is a 4 inch depth for most situations where health and development are prime considerations. When showing a refined tree with well established root ball shallower containers are often selected for temporary use. If I could make a suggestion it can help to consider some design characteristics when selecting a pot. Because your tree has a smaller trunk at this point compared to the deeper pot. A pot with different feet and a smaller lip may improve display and better complement the tree at this stage.
The choice of a lighter color is not a bad thing to consider if you wish to lighten the feel or diminish the mass of the pot when selecting a deeper pot. Here are a couple of optional designs to consider. I know the sizes of these particular pots are not suitable, just showing them to generate ideas.
Last suggestion, Use inside measurements as other have suggested to ensure fit. Every design varies the actual root space, outside dimensions are unreliable in that respect. My eye suggests the current pot may be longer and wider than needed for the trees current size. The caveat is how well developed and trained the root ball is at this point.
Four alternate pot shapes that may suit.
I should also mention that I would not invest in a more expensive long term pot until you explore the root ball yourself and refine the design for the tree. If you compact and refine the tree as well as the root ball over time the pot size and style may vary quite a bit as the tree matures.

 

[Rgw66]

With Pines a well respected guideline is a 4 inch depth for most situations where health and development are prime considerations. When showing a refined tree with well established root ball shallower containers are often selected for temporary use. If I could make a suggestion it can help to consider some design characteristics when selecting a pot. Because your tree has a smaller trunk at this point compared to the deeper pot. A pot with different feet and a smaller lip may improve display and better complement the tree at this stage.
The choice of a lighter color is not a bad thing to consider if you wish to lighten the feel or diminish the mass of the pot when selecting a deeper pot. Here are a couple of optional designs to consider. I know the sizes of these particular pots are not suitable, just showing them to generate ideas.
Last suggestion, Use inside measurements as other have suggested to ensure fit. Every design varies the actual root space, outside dimensions are unreliable in that respect. My eye suggests the current pot may be longer and wider than needed for the trees current size. The caveat is how well developed and trained the root ball is at this point.
Four alternate pot shapes that may suit.

This is wonderful. Thank you. I was actually looking at the top left pot here for some of the reasons you stated. It looks like it has an internal depth of about 4 inches and has zero lip. Part of me does like the lip though because it gives the appearance of a thinner pot.:

18″ – 20″ Unglazed Oval Bonsai Pots – Wigert’s Bonsai

I just called a bonsai nursery in the area (Meehan's Miniatures for those familiar). I spoke with the owner and she suggested that the pot it is currently in is likely perfectly sized for this tree and suggested that if it does need to be repotted, it could probably just be put back in the same pot. She said in a deeper pot, she would be worried it would be overwatered. So now I am unsure what to do. Who knew pot selection would be so nuanced

 

[River's Edge]

She said in a deeper pot, she would be worried it would be overwatered.

This comment is ridiculous. Bonsai are watered when they need watering! This is determined by many variables. A shallower pot in itself does not prevent overwatering, nor does a deeper pot cause overwatering.

 

[snowman04]

This comment is ridiculous. Bonsai are watered when they need watering! This is determined by many variables. A shallower pot in itself does not prevent overwatering, nor does a deeper pot cause overwatering.

So true, Frank! I have killed a few trees overwatering them in shallow pots because I thought they would dry out sooner...

 

[Rgw66]

She has been repotted! Thanks all for the help! And thank you vp999 for the pot!


I think the new pot looks great. The lighter color makes the rest of the tree pop. The deeper pot and the slightly smaller length and width definitely makes the tree look taller than before.

When should I fertilize? And should I keep it shaded for a a week or two or should give it full sun right away?

 

[Japonicus]

She has been repotted! Thanks all for the help! And thank you vp999 for the pot!
View attachment 588615

I think the new pot looks great. The lighter color makes the rest of the tree pop. The deeper pot and the slightly smaller length and width definitely makes the tree look taller than before.

When should I fertilize? And should I keep it shaded for a a week or two or should give it full sun right away?

Full Sun is good except during breezy days.
Fertilising, if I'm repotting that year, I wait for
candles to extend fully, pich off 50% or more
of each candle as it begins to open at the top
then fertilise when fully open. Fish emulsion is fine.
Then limited Fertilising till late Summer.
Then full strength.
If I'm not repotting that year, definitely no
fertiliser till late Summer save for a couple
applications of fish emulsion. Just not before
candles open and extend no more.
Spring fertiliser causes longer candles/internodes. Also I pinch off 75% of each
candle as it begins opening = shorter needles and internodes.

 

[Japonicus]

Late Summer is when the candles harden off.
Evidenced by shedding of needle sheaths.
Then we want to build reserves fertilising.
Full Sun all growing season.

 

[tanlu]

She has been repotted! Thanks all for the help! And thank you vp999 for the pot!
View attachment 588615

I think the new pot looks great. The lighter color makes the rest of the tree pop. The deeper pot and the slightly smaller length and width definitely makes the tree look taller than before.

When should I fertilize? And should I keep it shaded for a a week or two or should give it full sun right away?

Any updates?

 

[Rgw66]

Any updates?

Tree is healthy and seems to be tolerating our crazy hot/humid/wet summer quite well. Candles came in quite short/small I think due to a combo of repotting/lack of fertilization/maybe stress.

Happy I repotted since I now know exactly what the soil comp is and am comfortable with it getting rained on every day.

I fertilized a few weeks after repotting and going to fertilize heavily in the fall and spring to hopefully get better candle growth next year.

Also going to wire it up and get some shaping going in the fall. Any artistic suggestions for shaping would be much welcomed!

 

[Japonicus]

Looking good.
Adams bonsai sells a better Spring application
than fertiliser. MicroMax
http://adamsbonsai.com/adamsbonsai2025apr19_020.htm since fertiliser will probably cause longer needles and internodes. It will turn moss black so you may want to remove any moss you for some reason might want to keep
Compressed soil can cause shorter needles too.
Count your blessings if you have shorter candles and or needles. BTW repotting alone can cause happy shoots that elongate more than desired especially, especially, if you're sizing up pots.
Has lead to long bare necks on my candles before for which I know no fix such as pinching candles as the neck is below the candle.

 

[tanlu]

Looking good.
Adams bonsai sells a better Spring application
than fertiliser. MicroMax
http://adamsbonsai.com/adamsbonsai2025apr19_020.htm since fertiliser will probably cause longer needles and internodes. It will turn moss black so you may want to remove any moss you for some reason might want to keep
Compressed soil can cause shorter needles too.
Count your blessings if you have shorter candles and or needles. BTW repotting alone can cause happy shoots that elongate more than desired especially, especially, if you're sizing up pots.
Has lead to long bare necks on my candles before for which I know no fix such as pinching candles as the neck is below the candle.

I think candle elongation in pines tends to be the result of energy gained from the previous year. Repotting will invigorate a pot-bound plant, but if it’s already growing vigorously then repotting will probably slow it down.

As far as moss goes, I’d remove any moss you see on or by the trunk because it will rot the bark, which takes forever to age on JWPs, especially grafted ones. Pulling it off bark will damage the bark, so I’d spray vinegar on it to kill it off. It can be brushed off after it dies and turns black.

 

[Rgw66]

I think candle elongation in pines tends to be the result of energy gained from the previous year. Repotting will invigorate a pot-bound plant, but if it’s already growing vigorously then repotting will probably slow it down.

As far as moss goes, I’d remove any moss you see on or by the trunk because it will rot the bark, which takes forever to age on JWPs, especially grafted ones. Pulling it off bark will damage the bark, so I’d spray vinegar on it to kill it off. It can be brushed off after it dies and turns black.

Very interesting. Had no idea moss rots the bark. I love the look of the moss at the base but I will remove it for the tree's health

 

[99 Mile Creek]

She has been repotted! Thanks all for the help! And thank you vp999 for the pot!
View attachment 588615

I think the new pot looks great. The lighter color makes the rest of the tree pop. The deeper pot and the slightly smaller length and width definitely makes the tree look taller than before.

When should I fertilize? And should I keep it shaded for a a week or two or should give it full sun right away?

I agree. It wouldn't have been a color that would initially come to mind...but it works rather well.

I'm thinking a red pot for one of my older black pines.

Well done!

 

[tanlu]

She has been repotted! Thanks all for the help! And thank you vp999 for the pot!
View attachment 588615

I think the new pot looks great. The lighter color makes the rest of the tree pop. The deeper pot and the slightly smaller length and width definitely makes the tree look taller than before.

When should I fertilize? And should I keep it shaded for a a week or two or should give it full sun right away?

I should have mentioned this before, but I think the pot size is way more in line with the size of the tree and makes it the composition more cohesive. I also wouldn’t have thought to use a cream-colored pot for a pine, but for a white pine, especially those with lighter foliage, it works. Well done!

As far as the buds go, the tree should be making fairly healthy, plump buds now if you’re fertilizing well, so expect to have fantastic growth next year. By the way, unless your candles are longer than 1 inch, I wouldn’t pinch. Just let the tree retain vigor. You could either prune back later that year or pinch the following year to balance that vigor.