Grow box/bed question.

[ACooke]

Hi all,



I was hoping for some input and advice on trying to mimic field-growing as best possible, or perhaps more concisely - growing some material at a good rate.



I don’t have the ability to plant directly in the ground but am able to put a 2000mm x 1000mm x 500mm deep bottomless ‘garden bed’ on top of some very sandstone-heavy and not-so soil-heavy heavy earth.



I expect that this would be a better avenue than flower pots?



My question are (and please add any additional thoughts if anyone has any):



1/ Is there anything i should particularly look for in a soil? Zone, i believe is 10b. It’ll be in the care of someone looking after the yard as a whole with minimal interest in bonsai - they’ll water it, but at the same frequency they’d water the other pot-plants, lawn etc. I can fertilize as required/desired, and monitor them weekly/bi weekly ish.



2/ Is there anything i need to look out for planting different species that close together? I was hoping to get 6-10 trees in there although maybe higher range is defeating the purpose of ‘field growing’, being so close together?



3/ Should i be putting then in root bags/mesh pots or similar? I wasn’t planning in it?



Would love any other info or advice.



Initially i was going to put a couple of JBP’s in there and i’d love to be able to plant a couple of different species alongside.



Thanks in advance

 

[dbonsaiw]

Ground growing will give you the quickest growth rate, but you can get very good results from using a wide and shallow grow box. Soil generally should be free draining and people will use a mix of inorganic/organic material to accomplish this depending on the zone and tree in question. Zone 10b seems to be warm, so maybe some organics in the soil to retain water is a good idea. There are multiple folks here from your neck of the woods who will likely chime in as well with better first hand experience down under. I make my grow boxes out of 2X6 boards and make them 17"x17" on the outside and 5.5" deep.

 

[ACooke]

I’ll be using a deeper box @18inch deep which sounds like it might not be ideal but was just what was readily available; sounds like it’ll just make it a harder/longer process getting in to a desirable pot at the other end of this.

thanks @dbonsaiw !

Ground growing will give you the quickest growth rate, but you can get very good results from using a wide and shallow grow box. Soil generally should be free draining and people will use a mix of inorganic/organic material to accomplish this depending on the zone and tree in question. Zone 10b seems to be warm, so maybe some organics in the soil to retain water is a good idea. There are multiple folks here from your neck of the woods who will likely chime in as well with better first hand experience down under. I make my grow boxes out of 2X6 boards and make them 17"x17" on the outside and 5.5" deep.

 

[River's Edge]

If I translate the grow box size correctly we are looking at a 6ft by 3ft by 1 1/2 foot depth grow box. For growing out trees I use a spacing of 2 feet minimum between smaller trees that I am thickening up. So on that basis I would plant three trees per grow box that size maximum. because they are planted pretty close together I would be sure to root prune the drip line at least once per year to ensure the root balls do not grow together.
Local advice for free draining mix that holds the appropriate amount of moisture would be best to obtain. They would be aware of local options and climate best.
I would suggest a larger particle base to ensure better drainage on the bottom of the grow bed. You mentioned a heavy soil at the base so you want to be sure the roots do not sit in accumulating water. If the base is heavy clay some drainage holes may be needed in the bottom layer/boards.
When I constructed these grow beds I placed 75mm lava as a rough coarse on the bottom with landscape cloth underneath the lava. The placed my soil mix above that with a permeable landscape cloth between the very coarse lava and the Bonsai soil mix. The mix I used was pumice and sea soil for grow out. 80 percent pumice and 20% Sea Soil. The Sea Soil was selected for organic content and extra moisture retention. This was easier for me to plan because I knew the amount and frequency of water to expect. I used an automatic irrigation system. Just some extra ideas!

 

[jevanlewis]

To add to the already good advice on soil choice, another factor influencing the mix of inorganic/organic will be the frequency the person can water the trees. If they are watering the lawn/other plants infrequently, you may not be able to go as free-draining/organic as you would want were you able to monitor and water daily. If that causes you to go more organic to protect against drying out, you are more susceptible to overwatering versus a more inorganic mix. However, a grow box can handle overwatering a bit better versus a pot, but make sure your grow box can sufficiently breathe and drain water into the ground beneath it.

In terms of mixing species, different species usually grow fine together assuming they each get the proper amount of water, sun, and root growth space. Specifically, if you pack them in to tightly, they might shade each other out. Also, if you are having someone water the grow box uniformly, you want to make sure your trees watering requirements are somewhat similar. Finally, each tree needs space to spread its roots, the space need depending on species and on how often you plan pull them out and prune their roots.

What types of trees are you planning, and what are the ages/sizes of them?

 

[ACooke]

If I translate the grow box size correctly we are looking at a 6ft by 3ft by 1 1/2 foot depth grow box. For growing out trees I use a spacing of 2 feet minimum between smaller trees that I am thickening up. So on that basis I would plant three trees per grow box that size maximum. because they are planted pretty close together I would be sure to root prune the drip line at least once per year to ensure the root balls do not grow together.
Local advice for free draining mix that holds the appropriate amount of moisture would be best to obtain. They would be aware of local options and climate best.
I would suggest a larger particle base to ensure better drainage on the bottom of the grow bed. You mentioned a heavy soil at the base so you want to be sure the roots do not sit in accumulating water. If the base is heavy clay some drainage holes may be needed in the bottom layer/boards.
When I constructed these grow beds I placed 75mm lava as a rough coarse on the bottom with landscape cloth underneath the lava. The placed my soil mix above that with a permeable landscape cloth between the very coarse lava and the Bonsai soil mix. The mix I used was pumice and sea soil for grow out. 80 percent pumice and 20% Sea Soil. The Sea Soil was selected for organic content and extra moisture retention. This was easier for me to plan because I knew the amount and frequency of water to expect. I used an automatic irrigation system. Just some extra ideas!

Excellent, thanks!

Does the annual root-pruning not hinder the growth to a level where it’d be comparable to potting individually? Or do you prune when they’re going in to dormancy so it’s not overly affected? Sorry - probably a silly question.

I don’t think water should sit at the bottom/around the root base - even though it is sandstone it’s not completely level so i’d think that will help with run-off, as well as the open base.

Thanks for the info, certainly a lot to think about and digest. Being that i’ll be looking at fewer trees than i’d hoped, that adds to the thought haha. (And yes your conversion from M to F looks correct to me).

 

[ACooke]

To add to the already good advice on soil choice, another factor influencing the mix of inorganic/organic will be the frequency the person can water the trees. If they are watering the lawn/other plants infrequently, you may not be able to go as free-draining/organic as you would want were you able to monitor and water daily. If that causes you to go more organic to protect against drying out, you are more susceptible to overwatering versus a more inorganic mix. However, a grow box can handle overwatering a bit better versus a pot, but make sure your grow box can sufficiently breathe and drain water into the ground beneath it.

In terms of mixing species, different species usually grow fine together assuming they each get the proper amount of water, sun, and root growth space. Specifically, if you pack them in to tightly, they might shade each other out. Also, if you are having someone water the grow box uniformly, you want to make sure your trees watering requirements are somewhat similar. Finally, each tree needs space to spread its roots, the space need depending on species and on how often you plan pull them out and prune their roots.

What types of trees are you planning, and what are the ages/sizes of them?

Yeah i don’t think an overly freely draining soil mixture as you’d normally use would work with the watering schedule. They won’t necessarily even get watered daily unless it’s hot, so it’ll be more of a ‘lets see how it goes’ than anything ideal - but it’s that or nothing.

As for species, id like to use a black pine or two, potentially a juniper or two, and something else - i’m not set on what yet, but i’ll be giving more weight to what could work than what i’d like most. (Although if i’m truly down to 3 trees it much 1 or 2 JBP’s and 1 other tree.

I’m not yet overly familiar with what will thrive most in my climate although junipers and JBP’s certainly do so.

Age wise, it’d won’t be overly expensive material so hopefully something approaching 10 years. Size wise, ideally something a little larger than Shohin.

Sorry, not the most concise answers - i’m beginning to realize i have more to think about than i’d thought.

I wonder if plating without root-bags would save so much inter-tangling of roots/allow an extra tree or 2 without hindering growth rate too much?

 

[jevanlewis]

I think watering needs should be similar enough for JBP and Juniper (but, please listen to others' advice over mine since I am only familiar with JBP).

Speaking about JBP size/age, although the most expensive and impressive trees are several decades old, there are some very nice (and expensive) 10-year old trees (See the "6-year JBP from seed contest" threads. It's quite impressive what some members have done in only 6 years from seed). On the other hand, 10-year old JBP that have just been left to grow can be relatively cheap, but they likely have long/leggy trunk and branches. The point I'm trying to make is, if you don't want expensive, you're better off getting a much younger JBP that is small enough that (1) you can still put some movement into the trunk, (2) you can build taper in the trunk, (3) has branches low on the trunk, and (3) has tight internodes and foliage close in. These things are extremely difficult to fix on a tree 10-year old JBP tree that hasn't been continuously cut back and shaped with the intent to turn into bonsai. Of course, my advice depends on what you consider to be expensive!

To avoid root tangle, root bags are an option. I haven't worked with them. Many on this forum use them and like them. Others complain that the roots get caught in the fabric. An alternative would be to plant in something like an Anderson Flat and burying that to let the roots grow out the bottom. But, if you are going heavier on organics, I would probably just plant in the ground and space out enough to prevent root tangle and/or prune around the drip line, as suggested by @River's Edge . Root prune in the spring, which is the time you would usually repot (exact timing depends on the species). This shouldn't impact growth much, if at all, since most of the root ball is unaffected.

 

[River's Edge]

Does the annual root-pruning not hinder the growth to a level where it’d be comparable to potting individually?

The root pruning is just around the perimeter to prevent roots from intermeshing with the tree beside it. So very minimal disturbance. I would do it just prior to the beginning of your grow season. Do not damage the roots just going into dormancy. It simply consist of using a spade to push straight down to divide the area between the trees in half. Hope that is expressed clearly!

 

[ACooke]

I think watering needs should be similar enough for JBP and Juniper (but, please listen to others' advice over mine since I am only familiar with JBP).

Speaking about JBP size/age, although the most expensive and impressive trees are several decades old, there are some very nice (and expensive) 10-year old trees (See the "6-year JBP from seed contest" threads. It's quite impressive what some members have done in only 6 years from seed). On the other hand, 10-year old JBP that have just been left to grow can be relatively cheap, but they likely have long/leggy trunk and branches. The point I'm trying to make is, if you don't want expensive, you're better off getting a much younger JBP that is small enough that (1) you can still put some movement into the trunk, (2) you can build taper in the trunk, (3) has branches low on the trunk, and (3) has tight internodes and foliage close in. These things are extremely difficult to fix on a tree 10-year old JBP tree that hasn't been continuously cut back and shaped with the intent to turn into bonsai. Of course, my advice depends on what you consider to be expensive!

To avoid root tangle, root bags are an option. I haven't worked with them. Many on this forum use them and like them. Others complain that the roots get caught in the fabric. An alternative would be to plant in something like an Anderson Flat and burying that to let the roots grow out the bottom. But, if you are going heavier on organics, I would probably just plant in the ground and space out enough to prevent root tangle and/or prune around the drip line, as suggested by @River's Edge . Root prune in the spring, which is the time you would usually repot (exact timing depends on the species). This shouldn't impact growth much, if at all, since most of the root ball is unaffected.

Great advice, thanks @jevanlewis

Yeh, i’m not concerned about actual age and am certainly more concerned with base/trunk movement and so on. There’s certainly some fantastic younger trees around, and likewise some underwhelming older trees.

Purely hypothetic. Would you think planting a Japanese Maple for eg. (Insert any differing species - assuming climate was a fit) in the same box would be an issue and if so, mainly due to feeding, watering/oxygen requirements?

Also, i wonder if partially segregating the trees with some corrugated plastic or similar would work/solve the root commingling problem without too many negative effects.

Thanks again

 

[ACooke]

The root pruning is just around the perimeter to prevent roots from intermeshing with the tree beside it. So very minimal disturbance. I would do it just prior to the beginning of your grow season. Do not damage the roots just going into dormancy. It simply consist of using a spade to push straight down to divide the area between the trees in half. Hope that is expressed clearly!

Yep, that makes perfect sense thank you.

I was toying with the idea of segregating with corrugated plastic or similar but the above sounds like an easier means of achieving much the same goal.

 

[Shibui]

A bottomless raised bed is essentially ground growing as the roots can grow with no restriction.
Raised beds always need more water than ground level beds but once a week should suffice most species depending on your natural rainfall pattern. Around the edges of a raised bed is always drier than the centre so trees planted near the edges of a 1m wide bed may not do so well.

Some species grow faster than others.
I now dig and prune tridents every winter. If I don't they end up with unmanageable roots. Annual dig and prune doesn't seem to restrict growth much if at all but as a bonus allows you to manage trunk taper much better than trees left to themselves for years.
Japanese maples and Chinese elms are medium growers and are usually left for 2-3 years at a time.
Pines and junipers are slow. They take up to 5 years to thicken substantially and roots don't thicken unduly so they are left alone with just occasional direction pruning.

I grow a lot of trees in grow beds at ground level. Trees are planted at around 50cmx1m spacing and grow reasonably well here. If aiming at larger sized bonsai maybe space them out a bit more to allow more growth.
There's no problem with roots growing together provided you have room to dig between the trunks when harvesting. The roots will be cut short anyway so no problem if they have intermingled in the meantime.

No need to use open or fast draining soil when growing trees. The soil will be removed at transplant and trees generally have no problem with a change of soil at transplant.

 

[River's Edge]

There's no problem with roots growing together provided you have room to dig between the trunks when harvesting. The roots will be cut short anyway so no problem if they have intermingled in the meantime.

True, but there is a benefit to the root ball development if stronger and longer roots are cut, forming more feeder roots within closer to the trunk.

No need to use open or fast draining soil when growing trees. The soil will be removed at transplant and trees generally have no problem with a change of soil at transplant.

This is also true, however it is an advantage to create a rootball more suited to bonsai work. The fast draining soil is much easier to work with when correcting root structure in transplanting and repotting. Improvements at each stage of growth and development results in a superior product. When working with a few trees taking the time to perform extra steps will be worthwhile. In a large operation where the intent is to sell the product before refinement the labour saving or cost saving of soil mixes may become the deciding factor. Note: I found the free draining soil easy to continue reusing over extended periods of time and easier to maintain. ie: weeding
Not arguing, expressing another aspect for consideration.

 

[ACooke]

Thanks for all the info, everyone.

I'll definitely be going for a more 'normal' draining soil mixture rather than I quicker draining one, mainly due to my inability to monitor watering and here in Australia drying out too much seems to be a scarier prospect than staying a little wet, which I think is probably unlikely with the watering 'schedule' they'll have.

Excuse my greediness and impatience here as I'm sure this has probably been best addressed by not being addressed haha.

Are the dimensions mentioned above which were quick similar @ 1 tree per 1000mm x 500mm and (a forget the exact) but 3 trees per my bed size (2000mm x 1000mm) a pretty solid rule regardless of size? Ie. they just don't do well much closer than that for anything of notable size. Or would for eg. something with a decent/thickish trunk size for something a little over shohin size allow say 6 trees @ 500mm x >650mm 'plots'? or even 8 trees at 500mm x 500mm 'plots'. Is that just simply too close and largely hindering the growing process as a whole?

 

[Shibui]

The smaller the desired trees the closer together you can plant. The larger you want them to grow the more space each will need.
One of the deciding factors is getting a spade in between the trees to cut roots when digging. 500 spacing is probably minimum to be able to use a shovel to dig them out.
8 at 500x500 puts the trunks at just 250mm (10") from the edges. That's as close as I would go to the edge of the raised beds because the outer soil will dry and heat up closer to the wall. I have found that veges do not thrive closer to the edges of my raised garden beds.

 

[ACooke]

Perfect. Thanks Shibui, that helps a lot.
I’ll think a little deeper about it but maybe 6 is the go.

 

[ACooke]

@Shibui sorry to annoy you with another question but noticed you commenting on a variety of the common JBP varieties.

Have you got any quick high-level advice on the pros/cons on the common varieties that aren’t typically noted? Ie. Yatsabusa is more compact, more prolific back-budding but pruning is more demanding - growth is slower (a lot?). I’ve heard Nashiki can be more temperamental? Grafing needs to be checked etc.

But any big glaring ‘things’ you think are note worthy especially being that you’re working in a similar-ish climate.

Thanks again, i really appreciate your time.

 

[Shibui]

Nishiki is the cork bark black pine. As far as I am aware can only be propagated by grafting which will mean a short section of trunk with no cork bark at soil level. One of the Melbourne growers has pioneered extremely low grafting very close to roots to counter this problem. Slow growth is just one of the problems I have heard of with cork bark pine. I don't have any and don't intend to have any.
Yatsubusa is compact. Not sure that it back buds any more than standard JBP but it does produce many more buds at every growing point so ends up as a dense mass of shoots. Provided you thin out new buds before they get too crowded it can be OK. Needs a different trim and prune regime to the ordinary JBP. Also almost always grafted, sometimes not on JBP stock. Good grafts on JBP stock can be seamless and undetectable but some grafts are glaringly obvious and so not so great for bonsai. I have a couple of these that I've grafted developing as small sized bonsai.

Standard species JBP are not usually grafted so no problem with obvious and unattractive grafts. They grow quite quick in our climate and may even produce 2 or 3 flushes of growth in a single season even without pruning.

Climate should not cause any issues with any of the cultivars you've mentioned.
Downside with most pines is that they don't bud on older bare trunks well so growing them on fast needs knowledge and technique or you'll end up with long, bare trunks and branches with clusters of foliage near the ends.

Most pine species are hard to obtain here since a total ban on import of all pinus material including seed to try to keep out a few pests and diseases.

 

[ACooke]

Nishiki is the cork bark black pine. As far as I am aware can only be propagated by grafting which will mean a short section of trunk with no cork bark at soil level. One of the Melbourne growers has pioneered extremely low grafting very close to roots to counter this problem. Slow growth is just one of the problems I have heard of with cork bark pine. I don't have any and don't intend to have any.
Yatsubusa is compact. Not sure that it back buds any more than standard JBP but it does produce many more buds at every growing point so ends up as a dense mass of shoots. Provided you thin out new buds before they get too crowded it can be OK. Needs a different trim and prune regime to the ordinary JBP. Also almost always grafted, sometimes not on JBP stock. Good grafts on JBP stock can be seamless and undetectable but some grafts are glaringly obvious and so not so great for bonsai. I have a couple of these that I've grafted developing as small sized bonsai.

Standard species JBP are not usually grafted so no problem with obvious and unattractive grafts. They grow quite quick in our climate and may even produce 2 or 3 flushes of growth in a single season even without pruning.

Climate should not cause any issues with any of the cultivars you've mentioned.
Downside with most pines is that they don't bud on older bare trunks well so growing them on fast needs knowledge and technique or you'll end up with long, bare trunks and branches with clusters of foliage near the ends.

Most pine species are hard to obtain here since a total ban on import of all pinus material including seed to try to keep out a few pests and diseases.

Awesome, thanks - that helps a lot.

I’ve luckily got access to several dozen yatsubusa and standard JBP’s and ~10 or so Nishiki locally (established/semi-established) raw stock). I haven’t looked closely at grafts and so forth yet so i’m not entirely sure what the quality is like - but i’m hopefully i’ll find a couple of winners in there.