Raised bed soil

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Shohin
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i plan on putting in a few raised beds this spring in my yard. Going to use them for trees I want to grow more and thicken the trunks. My question is what kind of soil should I put in them? Is just plain top fine or should I mix anything with it like live park, small rocks or sand. Obviously I can't fill them with pumice lava rock and akadama since each one is going to be 8'x4'. Just didn't know if a mix to make it a little more free draining would be better than straight top soil.
 
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First you have to tell us what kind of trees. Different trees need different soil even when "field growing"
 

Spdyracer

Shohin
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First you have to tell us what kind of trees. Different trees need different soil even when "field growing"
Good point sorry about that. Most would be local deciduous trees like maples, hack berry, mulberry and other similar trees. May have a few junipers but that would be the exception.
 

Anthony

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Placing the tree [ and on a tile is optional ] in a colander, before planting into the growing bed helps.

We use grow troughs roughly 8 feet long and about 2 feet deep, they are built on top of concrete floors.
The soil is a basic top soil blend [ read loam ] that has been slightly modified with some 5 mm gravel to enhance
drainage.

This soil can grow junipers / pines, evergreens/ deciduous and anything else we have thrown at
it. Since we use a fridge, we can also grow anything non-tropical that can handle a top temperature of around
86 to 90 deg.F [ 30 to say 33 deg.C ] - eg. Celtis and Ginkgo and in the past we did the Trident maple.

Best of luck.
Good Day
Anthony
 

BrianBay9

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Like Anthony I use topsoil amended with something inorganic for drainage - whatever is handy. Throughout the year I add used bonsai soil after repotting, etc and work it in.
 

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Like Anthony I use topsoil amended with something inorganic for drainage - whatever is handy. Throughout the year I add used bonsai soil after repotting, etc and work it in.
The old bonsai soil is a good idea I'll have to remember that. About what ratio do you use with soil and inorganic?
 

Giga

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I have 3 beds and honestly anything works, I use soil conditioner, old bonsai soil, turface mvp and high quality manure or compost. I've planted any and every thing in them and have never had a issue.
 
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You can use most anything without issue, BUT........

The thing you have to keep in mind is you are trying to do the equivalent of field growing to thicken trunks. To get that result as quickly as actually sticking them in the field ground, the ecology needs to be the same as if it were going to be in the actual field, but with the addition that in your case, it also needs to be well draining.

A few things that make a huge difference in the field vs. in a bed in terms of ecology or to be more specific the micro-ecology.

1: Beneficial root fungi. This exists in nearly all top soil that is within a mile of any other tree. Endomycorrhizal fungi and Ectomycorrhizal fungi, as well as Trichoderma. They form a symbiotic relationship with the roots of nearly all plants and trees helping them to reach more water and nutrients and better absorb minerals. Thus greatly increasing a trees growth rate. Also they inoculate against many types of harmful fungi. You can find all kinds of this stuff for sale. I could write a book on the topic but nobody here wants to read all that.

2: Soil Organic Matter. This is the animal and plant residues at various stages of decomposition. The best "time release" fertilizer in the world, and also needed to keep your beneficial fungi alive. There are hundreds if not thousands of micro-organisms as a result of this in your soil, all of them are important to your trees growth and health. I could also write a book about this here, but I'll save everyone the 5 page reply.

3: Worms. There is likely no tree that you cant dig a hole near and not find worms. Not only do they help get more air into the soil, they leave behind castings from eating your organic matter which is another great natural fertilizer. Depending on how deep your raised bed is, the best worms you can find for this are called Red Wigglers. Just google it, they are not that expensive and work wonders. They are the best little root farmers you can hire, and they work for scraps. Literally.

All of the above builds a similar micro ecology to what a tree will have in the ground, the nice thing is once you get a good micro environment going it will live for hundreds of years as long as you supply the organic matter and don't kill off your fungi with fungicides or high doses of fertilizer. So.... Although the cost of starting out might be around $100 for a couple of raised beds, as long as you tend them you'll never spend that money again and you will have an amazing place to "field grow" your trees with great results and quickly.

Our 4'x12'x 2' deep beds consists of inorganic pro mix and compost (75% inorganic 25% compost) Then we mix in to that mix about 5% lava sand to balance PH, and increase drainage and 1 bag of perlite for drainage as well even though there is perlite in the pro mix. We use 2 bags of mycorrhizal fungi per bed, there a lots of brands but we found that rootgrow has the highest spore count per tsp so we use that, we also mix in 1, 1Oz. bottle of great white brand for the trychoderma it offers. Then we put in about 500 red wiggler worms to start the bed, they breed quickly so in no time you will have thousands in your soil mix.

We have seen equal, and sometimes better results in our beds as compared to the trees that we literally put in the field with a tile below them. In most cases for the shrubs the results are 25-30% better than in the field (shrubs being junipers in most peoples cases) Trees are just as hardy as the ones in the field, and depending on how the micro ecology is working we often find that after 2-3 years of being in the raised bed the trees out-perform the ones in the actual field.

If you have a season where you wont have trees in them, grow potatoes, it will help the micro-ecology thrive and be super ready for the next batch of trees.


Sorry for the short book reply, I was a horticulturist before a bonsai artist and for me the science of growing magnificent trees is just as much an art form as styling and wiring them.
 

_#1_

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@Woody Carverton what inorganic do you use for that 75%? I'm going to be mixing soil soon for my 11x7x1.5 raised grow bed soon. I'm calculating way more than $100. But my math sucks though.

Thanks.
 

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Sorry for the short book reply, I was a horticulturist before a bonsai artist and for me the science of growing magnificent trees is just as much an art form as styling and wiring them.

Don't apologize for the great info gives me so much to consider when building the beds. The fact you have seen better results is a big reason why I want to build a few beds. Also want to be able to keep the trees I'm growing close to my other trees in pots so I can make sure they get taken care of the same. Thanks for all the info. I'll have to research a few of the ideas you have brought up.

Do have one question that may tie into your #1 and 2. My father n law lives right next to me and has horses. Would it be a good to use there manure in the soil?
 
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@Woody Carverton what inorganic do you use for that 75%? I'm going to be mixing soil soon for my 11x7x1.5 raised grow bed soon. I'm calculating way more than $100. But my math sucks though.

Thanks.

We use SunGro Horticulture's ProMix. We buy it by the pallet which GREATLY reduces the costs. But there are a lot of things you can use that are just as inexpensive, The cheapest way is to grow large beds of peat moss then dry them or go to your local saw mill and buy a pickup truck load of bark. We use to do it that way until we got big enough that it just made more sense to buy a ready made inorganic mix to save time.

Also i should have added that 75% was just a starting figure, as the ecology settles in your soil mix turn's more organic by the year, its just best to start with a large inorganic component to keep things balanced. We only turn our beds every 7 -10 years and even then we recycle everything we pull out. If you plan to turn your beds more frequently you can use a little more organic to start.

To save money, you can replace lava with river sand. Literally take 5 gal. buckets to a river, put on the boots and get out away from the banks to find pure sand. Also you can get away with 1 bag of fungi, get a large Rubbermaid tote, fill it with garden soil, mix in the fungi and plant some potatoes in it. After you harvest the potatoes pull out all the roots, chop them up and throw them in your raised bed, you will have essentially quadrupled your fungi count by growing it yourself.
 
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Do have one question that may tie into your #1 and 2. My father n law lives right next to me and has horses. Would it be a good to use there manure in the soil?

Mainly depends on what he is feeding them, but in most cases yes, but only as a topical dressing. You will want to get a LOT, then spread it out on tilled earth. Throw some worms in it then let it sit for about a month, let it sit until it dries out about 60-70% and is more fluffy. Then mix spread a light amount on the top of your soil and "wash" it in. If you dont already have one, i would buy a Dramm 1000PL water breaker and wand for this as to not disturb the ecology. Only do this in early spring, and late fall.

Honestly, anyone who has a living raised bed (living means micro ecology) should have a Dramm 1000PL. It is the least disruptive head on the market and also adds a lot more air to the soil than any other watering method.

(
) Skip to about 1:25 to see one in action, its the only video i could find that had a good demo on how light and fluffy the water comes out without making one myself.
 

GGB

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I love frugal / free gardening and I don't get fancy. BUT, as a lover of pines, I ALWAYS add a soil acidifier to my growing beds, a little goes a long way. I'll amend the soil with anything that doesn't hold water (basically any stones i find get tossed in). I am a novice, but have a very low mortality rate, just food for thought. Oh and I second @Woody Carverton ecto/endo mycorrhizal (spelling) fungi is worth the 5 bucks
 
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