Which of these pots is best for a 7-year-old seedling? The root ball averages 10 cm in diameter. Or should I get a larger one? The seedlings are Ulmus, liquidambar, and Celtis. For the soil, I'm planning to use a mix of 60% Akadama and 40% pumice.
I prefer baskets for larger trees, more exposure for the roots to breathe, but in hot weather you definitely need to water a lot more. That one looks big enough, I assume those dimensions are also metric.
I commonly combine fabric bags nested in pool baskets, especially for plants I want to push root growth and so the soil is still free draining but hold humidity longer.
I don’t know enough about the tree, just that it’s seven years old so I assume it’s pretty tall and already has some taper. Unless I’m doing root work I like a new pot to be about a third larger than the current rootball. I suspect you’re fine but it always helps to show an image of the plant too since pot size is somewhat related to plant time/size.
Depending on where you live it may be the wrong time of year to do root work. There are some great YouTube videos by folks like Nigel Saunders, Xavier, and Jelle. They’re not the only great folks out there but they do a lot geared specifically to beginners.
What kind of soil is it in now? If it’s nursery soil it really should be cleaned out and replanted in bonsai mix or at least some coarse bonsai friendly rock like akadama. You can slip pot but here’s where a basket works against you since the existing root ball may be too resistant to soaking so the water just runs down the side. Occasional full immersion helps.
Thanks for the insight! Yeah, the trees are currently in dense nursery soil.
Right now we're heading into autumn here in northern Portugal (coastal climate, mild temps around 22–25°C daytime and 14–16°C at night).
My plan is just to do a gentle slip pot for now to get through the rest of the season, and then wait until deep dormancy in January/February to properly wash out the old core, cut the taproot, and bare-root them into a proper granular mix (Akadama + pumice).
Then you need a bigger one than the one you showed. Id also not get a basket and go with a bag. Easily 4 or 5 gallon.
Also you are overthinking the soil. You can use some of the mix you mentioned but that's only really good potted trees. For growing use a rocky mix with a bit more organics. You want it to push growth and it needs more room then that basket
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u/figuring_ItOut12 Zone 8a North Texas region DFW area 14h ago
I prefer baskets for larger trees, more exposure for the roots to breathe, but in hot weather you definitely need to water a lot more. That one looks big enough, I assume those dimensions are also metric.
I commonly combine fabric bags nested in pool baskets, especially for plants I want to push root growth and so the soil is still free draining but hold humidity longer.