Soil progress

kingkong

I just can't stop digging up the soil around the jbp. It's hopeless. Experimenting with three soil mixes in the ground. Silica sand mix, soiless aggregate mix and peat nursery container mix. Wouldn't you know it, the one I am trying to stop using. The one nobody recommends is by far rooting the best. I am not sure what to think but the peat mix is way ahead.

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Graydon

Sounds fair but remember - we are in this for the long haul. Peat based stuff will collapse long before the others you listed. The longer they go before root disturbance the better they will be.

On a similar subject George (you met him at the Schley's when we met) brought in a JBP to our club meeting last night. We potted 200+ of these mid November. This one had roots growing from the drain holes already. The root mass was selectively reduced by at least 50%. I checked mine like it today and there a little root tips growing thru the bottoms of most of the colanders.
George's are in turface and pine bark, mine in a lava, pumice and akadama. I suspect no difference in root growth at all.

By the way - do you keep touching wet paint to see when it's dry?

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kingkong

I think it must have something to do with their preference for acid soil, 5 to 6.5 pH range.

Colin Lewis

I missed the brginning of this thread, but from what you say it seems you are getting exactly the same results as I did. In the early nineties, when I was publishing the UK Bonsai Magazine (now a part of Bonsai Europe) I ran some fairly scientific tests.

I got five other people, as well as myself, to grow scots pine and larch seedlings and elm cuttings in several different soil types. Two of the five had no horticultural experience. Soil types included akadama, peat, turface, garden soil and sand - plus a fairly standard bonsai mix. Everyone grew one of each species in each soil type - eighteen plants each. All were foliar fed only.

With no exceptions, peat stimulated the most prolific roots and largest plants. Sand gave a lot of root growth but slightly less bio mass. Next came akadama, turface and finally garden soil.

This is how seedling roots behave after one season, but that does not mean the same would happen year on year, or with older more sedate trees.

I believe this result has to do not so much with the moisture retention properties of the soils (sand holds little) but more with how available the moisture is to the roots. Peat and sand are both very fine with tiny interparticle spaces. Wherever roots want to go they can and they will always be in contact with available water.

Fast forward a few years to a nursery plant growing in pure peat-based compost, and you're potting it down. The roots are very fine indeed and they form a dense block that is impossible to comb out - right? That's the problem with peat as a long-term growing medium.

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COLIN LEWIS
www.bonsaideals.com
www.bonsaiforum.com

Graydon

Thanks for summing that up better than I could Colin.

Here's a follow up question - would it be prudent to start pines in a peat based mix as kingkong has done and let them grow unchecked for a year - and then remove the soil, do some root selection and correction and repot in a faster draining, larger particle mix for a better nebari development?

I ask as I have access to 75 JBP seedlings that someone else started in such a mix and have tons of fine roots as well as some beginnings to good nebari. I have begun to work them out of that soil in to a better soil mix for the long run. Too early to see results yet, just curious as to your opinion.

Good thread kingkong - you're a thinker for sure!

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kingkong

Just visited a nursery that was growing the healthiest, most robust slash pine ( Pinus ellioti) I had ever seen. Young pines, 3 feet tall, 2-3 inch calliper trunks, multi low branching and dark rich green. Too my suprise they were planted in huge 40 gallon pots with sray stick irrigation. The soil is a canadian peat, pine bark, coconut husk, sand mix. The secrete according to owner is the pots drain very well and the soil is loose. They are to last in this environment up to 2 years before sold. Typically, this is a hard pine to grow so well. Got one so I can dissect the root ball, you know, the part I enjoy the best.

Colin Lewis

I think so - or even up to three years. After that the peat will deteriorate. It's important to get a good root system working for you early on. For some reason seedlings do better in this humus-rich and acid environment. I wonder if it has something to do with the fact that they're designed to germinate in leaf litter... I favor those nursery pots that are shallower than normal flower pots. I think they use them for bulbs or chrysanthemums.

I like to get the nebari nice and wide first, wider than you would think, for this reason: Imagine a young trunk,half an inch thick, with nicely spaced nebari spreading out to a radius of two inches all round. Wide enough? Now think ahead ten years. The tree has been in the ground for four or five years, then in a large growing container. The trunk is now two inches thick, but the nebari is still only four inches across. An inch-wide nebari all round? Not enough by any means.

It took me twenty years to figure that out!

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COLIN LEWIS
www.bonsaideals.com
www.bonsaiforum.com