Gravel from my yard for "developing" trees?

[Harewood Hobbyist]

I am looking for some thoughts, anecdotes, peer reviewed research, et cetera for making my own soil in a long, wet winter and short but hot, dry summer climate (Vancouver Island).

For context:

• Being of the generation and region I am from, I've grown trees, ornamentals, and various vegetables in pots for upwards of 20 years as I have moved around from shared house to apartment to cabin to another apartment and so on. This was always in nice big deep pots in almost 100% organic matter.
• I have been "doing bonsai" for less than a year. This mostly means digging up and/or repotting small trees into shallow pots.
• The main lesson learned so far is to shun organic matter almost totally in my soil mix. It seems easier to water more in the summer heat than it is to water less when it rains all the time.
• For tiny plants in tiny pots, I use diatomaceous gravel with the dust rinsed off.
• For larger plants (probably nothing over a foot tall) that I am "developing," I use half perlite or pumice and half diatomaceous gravel.
• These two substrates seem pretty good. Tiny plants are doing great with very few exceptions. Larger plants that went into the half perlite half diatomaceous gravel mix are mostly still living, several are thriving.
• Pumice is pretty cheap when bought in bulk but I don't have a good spot for the dump truck to dump.
• BUT I want to spend less money on this early, experimental, non-refinement stage of learning "to bonsai."

Because the tiny potted plants are a tiny volume of substrate and therefore low cost, I intend to keep using diatomaceous gravel and try out akadama next winter/spring.

For my larger plants, mostly in wooden boxes on the ground out back, I am thinking I will switch over to using whatever mostly inorganic soil I can find near me and sift it to remove everything over 1/2" and everything under 1/4".

What is wrong (or right) with this path?

Thanks

 

[LemonBonsai]

I am a noobie as well. However I will say something i've learned with soil through trial and error. At first I used half perlite and half oil dry or hard clay particles sifted. However I found that when I added potting soil to this mixture of perlite and oil dry I got way better growth, as well as great drainage. I don't put alot of potting soil, but I probably put in 1 part potting soil to 2 parts of my mixture. However I also mostly have trees in training, When trees are young ive learned that organix soil is good as long as drainage needs are met, and once you get your foundation laid out, switching to non organic, gritty soil helps with slower growth, tighter growth.

To give an example last year I started 6 lemon seedlings in my original 50/50 perlite and oil dry probably half way through summer. maybe a month after I started those I started 3 others in pure potting soil, which was stupid but I wanted to experiment and lemon seeds are easy. Now, the ones I planted in potting soil are 4 times the size of the ones planted in the original mix, and they are technically younger!

So I found for me, a happy medium between the two is what works for me.

 

[HoneyHornet]

Wish i knew where to get pumice by the dumptruck..nd i did hardscaping for years nd been to tons of rockproduct n landscspe supply places lol looks like i need to look again

Other cheap inorganic sub i really like is fullers earth..i buy it in form of safe t sorb oil absorber

My only comment would be to not feel tho u cant use any organic..many do 60 40.. Especially during grow outs whether it be in ground or large container...you an even use screen or mesh for bottom of the growbox for max drainage..i fluff with an excellent organic compost mix called Bumper Crop (blue bag) and works great

 

[HoneyHornet]

Comment above me came in before I finished sent mine and I agree with that oil dry mix lol

 

[Harewood Hobbyist]

oil dry

I use the Qualisorb brand from cantire, diotomaceous gravel mined in Quebec.

Your right and I agree that organic soil should promote more growth. I think you get a lot less rain in Ontario. But lemons mean you are probably growing under glass and have a lot of direct control of precipitation? I am experimenting with ozmocote for the first time re growth. IDK how this will work out

 

[LemonBonsai]

I use the Qualisorb brand from cantire, diotomaceous gravel mined in Quebec.

Your right and I agree that organic soil should promote more growth. I think you get a lot less rain in Ontario. But lemons mean you are probably growing under glass and have a lot of direct control of precipitation? I am experimenting with ozmocote for the first time re growth. IDK how this will work out

Actually no i dont grow in a controlled enviorment except in winter of course. But we do get a decent rainy season here. The key to that is to make sure drainage is still the most important factor. If the soil is well draining it could rain as much as it wants. If I left my lemons in pure potting soil then id be in trouble, I have since moved them to my new and improved soil.

 

[Paradox]

Gravel is going to make the trees very heavy to carry around. Also gravel is not particularly porous so it will not retain much nutrients or moisture.

I used to use a gravel/sand mixture
It was VERY heavy and it tended to compact which retarded good root growth.

I've used a lava : pumice mix with developing trees in larger pots with good results, much better than the gravel - sand mix.

If you are worried about expense, limit the number of trees you keep to a number you can afford to support with the proper soil.

 

[Harewood Hobbyist]

@HoneyHornet

There are pumice mines not that far from me. My estimate was a dump truck load would cost me under two grand and last me for a decade or two. Storage tho

I have been avoiding fullers earth because it is just clay? It will turn to suffocating mud on the wet coast?

 

[Harewood Hobbyist]

Gravel is going to make the trees very heavy to carry around.

I have joined the landed class and no longer need to move plants from renoviction to renoviction. I can have my serfs lift the pots if need be.

tended to compact which retarded good root growth.

This is a big deal and I already knew this but I guess wanted someone else to remind me and thus disabuse me of my gravel solution.

limit the number of trees you keep to a number you can afford to support with the proper soil.

Sound advice but no

 

[Paradox]

I have joined the landed class and no longer need to move plants from renoviction to renoviction. I can have my serfs lift the pots if need be.

I am not familiar with your climate. Do you not need to move trees in the early winter for winter protection and back to your benches in the spring? You can leave them out all winter on the benches with no protection?

sound advice but no

If you prefer to have many trees with suboptimal health and suboptimal growth instead of fewer healthy trees with vigorous growth, that's your choice but good luck trying to bonsai trees that are not healthy

 

[HoneyHornet]

@HoneyHornet

There are pumice mines not that far from me. My estimate was a dump truck load would cost me under two grand and last me for a decade or two. Storage tho

I have been avoiding fullers earth because it is just clay? It will turn to suffocating mud on the wet coast?

..ya clay but i mean its treated at 800 to 1000 degrees and puts in a few seasons for me before repotting anyway

Wouldn't be the first person convinced its not suitable LOL

And it's the main ingredient for most oil dri products which ppl def hve used.. mixed with lava rock and Fir bark and a smidgen compost it does me good

Just offering alternative because you mentioned saving money

 

[Harewood Hobbyist]

I am not familiar with your climate. Do you not need to move trees in the early winter for winter protection and back to your benches in the spring? You can leave them out all winter on the benches with no protection?

I am not 100% sure how the trees will respond to winter in a shallow pot but I am mostly doing native species whose ranges extend into much colder areas than my place. Altho that can be really deceptive, a lot of alpine species can't handle hard freezes and they don't have to because the snow pack protects their roots from going as low as freezing, for example. Where as I get a couple weeks of snow a winter but not enough snow to really protect them from the cold. IDK.

By saying that "I can have my serfs lift the pots if need be" I mean that I own this house and this yard and I will not be renovicted by the landlord; the substrate can be heavy because I won't be moving hundreds of potted plants on short notice.

 

[Paradox]

I am not 100% sure how the trees will respond to winter in a shallow pot but I am mostly doing native species whose ranges extend into much colder areas than my place. Altho that can be really deceptive, a lot of alpine species can't handle hard freezes and they don't have to because the snow pack protects their roots from going as low as freezing, for example. Where as I get a couple weeks of snow a winter but not enough snow to really protect them from the cold. IDK.

By saying that "I can have my serfs lift the pots if need be" I mean that I own this house and this yard and I will not be renovicted by the landlord; the substrate can be heavy because I won't be moving hundreds of potted plants on short notice.

lol ok.
FYI I also own my house and I leave my trees out in the fall as long as I can.
I have gotten surprise freezes in the fall that required me to move trees into the cold frame the day or two before.
I have somewhere around 50 (too many) and I've moved them in about 2 hours when we got a freak early fall freeze.

 

[HoneyHornet]

I use the Qualisorb brand from cantire, diotomaceous gravel mined in Quebec.

I have not seen your use of De probably because I was posting from work but yes that product is just like Ultra sorb which I like as well for some reason the Fullers based absorbance are more available by me but I'm a fan of all those Oil-Dri type products for cheap substrate.. if I had read more thorough through your description I wouldn't have bothered pointing that out

 

[ShadyStump]

I have had a fistful of trees in a mostly gravel mix in very large pots for the past year or so, with dubious results. By that I mean none of them are doing well, but I'm fairly certain it's other factors in care (or lack there of; trees were dropped in priority as other things came up) more than the soil/substrate.

I mixed standard granite road gravel- cheap and available here, but very large particles- with soil from a section of the yard that I know had been heavily composted over the years so would not compact. Drainage was excellent while retaining enough moisture to not have to water our native (semi-arid climate) plants several times a day.

But yes, HEAVY. Get a sturdy hand truck, but it will certainly work.