It's sometimes difficult to obtain pine bark on the left coast because of the huge volume of fir and redwood bark by-products there. These products are also well-suited as a substantial component of most container and raised bed (RB) soils, primarily because they are rich in lignin and suberin, which are very good at defeating micro-organisms' attempts at cleaving the hydrocarbon chains that make up the bark. Since they break down so slowly, N immobilization is a factor, but it is minimal enough that you can manage it by using a product that is high in N. I'll come back to this in a minute, because the bark route is the way I decided to go, so I can describe how I made the soil for my raised beds & you can decide how you want to proceed.

You can also do what LazyG (sounds like her rapper name) ;-) suggested in another thread - mix about 1 part of compost to 2 parts of native soil (or good topsoil if your native soil is unsuited) and call it good. This is fast & easy, and shrinkage won't be much of a problem. I will say though, that if you are not growing plant material that needs renewing each year (annuals & veggies) the shrinkage you DO get will cause the plant's roots to become exposed, unless you stay right on top of adding additional soil or compost.

Here is a picture of the soil in my raised beds:

{{gwi:871}}

It's a very productive soil and abundant with all the tiny denizens that make up soil life. You can see it also has excellent tilth. It drains well yet still holds lots of moisture. The soil is comprised (originally) of approx
5 parts partially composted pine bark fines
2 parts sphagnum peat (could also use 2 parts Michigan or reed/sedge peat, leaving out the sphagnum)
1-3 parts Turface or NAPA floor-dry
1-2 parts builders sand or native topsoil
dolomitic lime
but I could easily have used more sand in this soil.

I know I was all over the place in what I just related, so I hope you're not confused. Please think of it as the opening to a conversation that you can now steer in whatever direction you'd like it to go. Please be sure to let me know if you have any aversion to using fertilizers other than strictly organic.

Al

I've thought about doing the topsoil/compost thing, since I'd never be able to dig up enough of the soil in my yard to make up any substantial portion of what I'll need. I've also considered Mel's Mix, but part of me really, really doesn't want to deal with peat because of the horror stories I've heard. If I did buy the topsoil, it'd be what the company calls "screened sandy loam". I'm not sure whether or not that would need another additive beyond compost to aid in aeration and drainage, or moisture retention. They also sell something called "nursery mix", but there isn't much information as to what's contained within (Description here). Recently, I visited a multi-million dollar home with a gorgeous garden, and asked what kind of soil they planted in. The answer, Lyngso's nursery mix with bone meal mixed in. So, it doesn't seem to be bad stuff, but one never really knows.

I'd like to go the bark fines route, and it seems like any mix I make will need some amount of Turface or floor dry (around $13/bag for the Turface, and $9/bag for the floor dry - any idea approx. how many sq ft. are in a 50lb bag of Turface, btw?), so I don't think I'll be able to get around the expense of that, but the other parts are sketchy. I guess since you're in MI, and Home Depot gets their products from regional suppliers, there's no chance that you'd be able to direct me to a product name to look for, in terms of bark fines, right? Would you happen to have a picture of what your fines looked like before they went into the mix? I know redwood isn't ideal because it breaks down so slowly, but since the place I'm buying from has "redwood compost", I'm thinking maaaaaybe that would serve as a substitute for the fines? The more I can buy in bulk, the better, since I'm going to need around 3cu yards of everything all told, and buying that much bagged material will send costs skyrocketing.

And nope, I don't have any non-organic fertilizer aversions. I mean, in a perfect world, I'd go all organic, but who am I kidding? Both I, and this world, are so far from perfect that a little Miracle Grow isn't going to tip the scales one way or the other.

{{gwi:1234}}

What I started with for my beds looked like something close to what you see at the top of the pic above, but it wasn't quite as fine.

A bag of Turface has 1 cu ft in it; a bag of floor-dry has a little less - maybe .8-.9 cu ft.

"I know redwood isn't ideal because it breaks down so slowly ...." Not so - that it breaks down slowly is an advantage you actually should seek for soil components, because there is less N immobilization to be concerned with. It also guarantees that it will retain it's physical properties longer, but that is more important if you were using it in a container medium rather than in a RB soil.

I've actually been thinking about this for quite awhile. You're going to want to end up with at least half of your soil a mineral component, so I'm thinking that a yard of the topsoil + a yard of the redwood compost is a good place to start. Because you guys get so little rain (I have a dear friend in Fremont and another friend in Walnut Creek), some vermiculite and floor-dry would be helpful. Let's talk about:

1-1/4 yard of screened topsoil
1 yard of redwood compost
10 bags of floor dry
3-4 cu ft vermiculite
6 bags reed/sedge peat
10 lbs garden lime
5 lbs High-N slo-release turf fertilizer (like 27-3-3 or similar)
A micro-nutrient source like Micromax would be very helpful until the soil biota gets going

Your thoughts?

Al

I know I shouldn't, but I can't help myself - when I see recipes, I translate it into dollar signs, lol. It goes something like this:

topsoil: $42.50
redwood compost: $29.00
delivery fee for topsoil + compost: $50.00
floor dry (the most painful component of all): $90
4cu ft. vermiculite: $34 (the cheapest I've been able to find it so far :()
6 bags peat: not really sure of the cost per bag... loose estimate of $10/bag = $60
10 lbs lime: haven't a clue of the cost or where to get it, lol
____________________________________________________________
$305.50... roughly, and without the lime

I'm trying to keep it right around $200-$225 for all, although I think that may be harder than it originally struck me as being. I'm bummed to hear that the 50 lb. bags of Turface are only a cubic foot. I was hoping for closer to two, so I could justify the $13 a bag. I know this is all an investment, and putting in good things to begin with that'll last for a while is better than putting in something crappy that nothing will grow in, and that'll need to be replaced or amended really heavily later, but yikes! Is one of the more expensive items in the mix swappable for regular compost? Or could I cut out the extra vermiculite since there's already floor dry? I'm sorry I'm being difficult, lol, but I'm trying to do it all on the cheap.

Oh - I don't think you're being difficult at all. You should see some of the questions I get in my mail. Sound the NERDALERT, but discussing soils and how to get to where you want to be when developing them is fun.

Sure - you can use regular compost instead of the redwood compost, but the $29 seems reasonable, and if you have to pay the delivery fee for the topsoil anyway ......

No reason you can't eliminate the vermiculite, too. It was only there to help with moisture retention and add a little volume.

Building a productive RB soil really isn't as complicated as building a good container soil. You can top-dress the RB to help with shrinkage and steady collapse of the organic component, and water retention isn't so problematic or as much of an issue because the earth below the bed(s) acts as a giant wick & 'sucks' all the loosely held water from the soil; the point being that you can get away with using material with much finer particles in RBs.

Here in MI, the sedge peat is about $3-4 per bag. It looks like muck, but it works very well incorporated into RB soils.

..... or you could always go back to the topsoil/compost thing and do ok, too.

No matter what you do, you'll need to watch for N immobilization & fertilize appropriately (be thinking 30-10-10 soluble). Fortunately, it's easily remedied & will likely only be an issue for the first year. The garden lime is cheap - about $6-7 for 50 lbs here. You do need it to supply Ca and Mg, especially if you use soluble fertilizers because most lack it.

.... ball's in your court.

Al

I love that you love talking about this because nobody I know seems to want to talk about dirt, lol. And nobody I know knows anything about dirt anyway, so even if we did talk about it, they'd just glaze over.

I was looking around here, and read that Hyponex (gross!) is mostly sedge peat. Is there any truth to that? If so, I can probably find it at Kmart or something for a couple bucks per bag, and that would bring down the cost by $48. If I swapped out the vermiculite and replaced it with a greater quantity of regular compost (they don't serve the same purpose, but I kind of want it in there just for the sake of bulking things up, and because my mind can't seem to get past wanting compost-compost in my mix, lol), that probably wouldn't change too much, right? Since there's already the Floor Dry?

I also looked closer at the soil supplier's website, and it looks like some things they sell in 1/2 yd. increments, and so I'm assuming the others require the purchase of a whole yard, or else I'll be out there bagging it myself and paying a premium per sq. foot, along with having to transport it myself (no truck here - booooo).

So maybe:
1 yard of screened topsoil
1 yard of regular compost
1/2 yard of redwood compost
10 bags of floor dry
6 bags hyponex
(other various amendments)

That comes to:
top soil: 34.00
reg. compost: 34.00
redwood compost: 14.50
delivery fee: 50.00
napa floor dry: 90.00
Hyponex (assuming it's $2/bag): 12.00
_______________________________________________
$234.50 + 9.25% tax (freaking California....)

That's a lot more manageable. Now, here's another question for you. Is there a benefit to using the redwood compost over using regular compost, or vise versa? Some quality that one or the other will have that gives one the edge over the other? The redwood compost they have looks almost like soil in and of itself already, if that gives you an idea of what I'd be working with.

I bought a bag of Hyponex soil to use for demonstration purposes when I talk about container soils or container gardening to various garden groups. It was very sticky & had lots of rocks in it - some the size of walnuts. I can't imagine it would be any less expensive than the reed/sedge peat, but ...... it's your choice.

If there is a difference between the redwood & regular compost, it might be in the fact that the redwood compost would be more stable. Often, commercially made compost is not 'finished' and will often tie up N as it continues to break down quickly in soils. The redwood, even if it's not well-composted will still break down slowly, which would minimize shrinkage (and expense down the road in having to replace the lost volume with more organic matter) and N immobilization. All things being equal, I'd probably opt for the redwood compost - especially if the price is a trade off.

Al

Oh, interesting with the redwood compost. It's cheaper than the regular stuff too, so I guess maybe I should let go of my compost issues and just go with straight redwood. It sounds like I'll need to find a good peat supplier too. So, in the end, the mix would be comprised of top soil, redwood compost, floor dry, and peat, yes? And that sounds like it'd be a good enough mixture?

Also, at what sort of store were you able to find the lime in such large bags? I think I checked Home Depot once and wasn't able to find anything.

For what it's worth, around here pine fines are sometimes called "soil conditioner". Ingredients on the bag label read "100% pine bark fines". I've never been able to find it sold it bulk (i.e. cu yards, by the truckloads). I really like it both for container soil or just as a mulch on the planting beds.

Karen

I think the mix you outlined will work well. Don't forget the fertilizer to start with. Most rural elevators/feed stores will have the garden lime, as will those places that sell fertilizers. Big box stores might only carry it as a seasonal thing. Espoma packages it too, so anywhere that sells their products will have it, but you'll pay as much for 10 lbs of Espoma as you would 50 lbs of generic.

If you go to the rural elevator/feed store, you might inquire about a bag of crushed granite of cherrystone (if you'd like to make a very good soil for your houseplants and long-term container plantings. The granite would be best in grower size and the cherrystone in #2 size. One or the other would be great. Then, a bag of the smallest fir bark from Lyngso's + some floor dry is all you need. Sorry for getting off track - just trying to help you kill 2 birds with one stone if you had interest.

Looks like you're in pretty good shape.

Al

I touched on most of the main points you made, Pam. The earth acting as a wick to reduce drainage concerns, that she could simply use a mix of compost and topsoil, .... so I would say that to argue the point would be like trying to decide where the lines are between adequate, good, and better. ;o)

YPA

I do kind of feel like I'm overthinking this all, to some degree. After only a moderately successful first year in my raised beds that I threw bags of potting soil into, I was hoping for something more successful for my fall garden in the new, currently empty raised beds that I've put up. I think that's why I've been so adamant about getting the right mix. I'll have to think it over a bit before I decide on anything. I really, REALLY appreciate all the input, Al and gardengal.

Question about the container mix, the landscape supply co. has crushed granite available in bulk also, but I'm not sure of the size or what it's generally used for. They sell it by the ton, so I assume it's usually used in very large scale projects. About the size of the white stuff in your mix photo above (btw, is that what Turface looks like?), or larger? Smaller? How would a Japanese maple, 2 keffir lime trees, and a Santa Rosa plum do in the mix? There isn't any place to plant them in-ground currently, so they'll be confined to pots for the foreseeable future, and I'd like to keep them as healthy as possible (though the limes have been in the same pots for several years and endured a lot of neglect and are still perfectly healthy).

The crushed granite or cherrystone that works so well in container soils for houseplants and long-term plantings is usually prescreened & about the size of BBs, or slightly larger. Turface is just a little smaller than that. See pic

{{gwi:4343}}

The gritty mix, made of equal parts of pine bark, Turface, and crushed granite is excellent for all your long-term plantings. You should learn about root-pruning though, as all perennials will decline in containers w/o attention to their roots. "Perfectly healthy" is a broad term. One person may look at a plant and feel it is healthy because leaves are green & it's not showing signs apparent to them that the plant is in decline, while a more experienced grower might look at other indicators and determine that the tree is stressed or growing under strain and not growing to its genetic potential.

Al

I certainly didn't intend to second guess you, Al :-)) I just can't see the benefit of the vermiculite, the peat or the floor-dry/Turface for a raised bed, provided one is using a 'reasonable' engineered soil blend rather than just topsoil (whatever that is) and/or compost. And as I go back and re-read, you did indeed indicate that streamlining the process should work.

YPP ;o)

FWIW Spaghetina, crushed granite, aka decomposed granite, is typically used for paving purposes, as once compacted, it generally becomes a nearly impervious surface similar to concrete, except for water penetration. Used frequently for walkways, patios, sometimes driveways and as a base under pavers.

Well, after all the thinking, rethinking and overthinking, I finally decided to bite the bullet and go the cheap route. I got 1.5cu yds. of nursery mix, and 1.5cu yds. of finished compost, and it was delivered at 9:30 this morning. I've been out there for 2 hours with intermittent breaks to rest my back, have lunch, and guzzle down some Vitamin Water 10 (ok, lots of breaks...) and I've got the 8x4 bed filled. There are three 4x4 beds left to do, and then all the cardboard I layed out right before we got gale force winds needs to be repositioned, and the mulch poured on top. I'm really wondering if this can all be done today with just me on the job. I've already contemplated driving down to Home Depot and hiring the guys standing around out there to come and do all this for me, but I don't think I'll get near as much satisfaction out of that, even if my back says otherwise.

The soil looks and smells really nice. It does seem a bit dense, but it is worlds apart from what I have natively, which might not really be saying much. I think, eventually, I'll be adding bags of Floor-Dry to it to give it a little more aeration and such, but that expense can wait. I really just wanted the dirt in without having to mix 3cu yds. of stuff in my driveway. So, I feel like I took the easy way out, and only time will tell what comes of that, but there's no going back now.

Al, I want to thank you for all your help. Your knowledge wasn't wasted on me. I plan on amending as time goes on, according to your specs. And gardengal, I'm so happy you chimed in as well. Both of you have greatly contributed to this project actually getting completed because if not for you, I would have sat here thinking about dirt for the next month without actually DOING anything about getting my hands on some.

Thanks, y'all! (Now back to shoveling dirt... )

Hello spaghetina, I see that your original quest is this: "I'm trying to build a soil for raised beds, and I just can't seem to hit upon the right combination of things or the right places/names of the ingredients to go into the mix. " I didn't see what you are wanting to grow, is it vegies, annual flowers, perennials or ?

For my raised beds in which I grow mostly vegies and a few flowers I don't buy ANYTHING. Well, we do pay for the screws to hold the reused lumber together. Inside goes the cardboard, possibly some wood chips on the bottom, old produce in large quantities, horse manure, leaves, and repeat the last three ingredients. Sprinkle in some crushed egg shells and a little wood ash from my stove, put some finished compost or soil on top if I have some, and viola'. I have excellent results with my vegies, flowers, and rhubarb in this.

Surely San Francisco has similar free items with which you could fill your beds? Maybe less leaves, but more grass clippings, coffee grounds, whatever. Since you mentioned not wanting to spend a lot of money, I am wondering why you are buying stuff when many of us do this with only a little gas money expended?

Marcia

Tapla,

As a "cheap" replacement for the vermiculite and having used a yard of screened year old horse manure as well, can I use shredded paper as an aid to water retention/ clay break up amendment? ( I live in the same city as one of your mentioned friends,... Fremont)

Sorry for butting in on the thread Spag

Led_zep, it'd be nice to use all free things, but although on a budget, I am also impatient. So, aside from not wanting to wait to find all the things to go into the beds (80 sq. feet + another 64 in the back that needs to be topped off) because I wouldn't have been able to supply them all on my own, I didn't want to wait for things to break down. Buying stuff, even reasonably cheap stuff, worked out to be my best option. All told, including the delivery fee, it came out to around $230, which is right around the amount I was hoping to hit.

Kiki, no worries! :) Ask away! I'm curious too. Btw, are you planting directly in the ground out there in Fremont? I'm in San Carlos, and oh man, the ground was IMPOSSIBLE to work at all. Kind of seemed like it'd take a jackhammer to get through it!

Kiki - you can use the newspaper, and in time it will help with the heavy/hard clay soil, but be aware that if you'll be growing in it too, it is likely to cause a considerable degree of N immobilization you'll need to deal with. One of the reasons I suggested the ingredients I did upthread was to minimize shrinkage and the initial N immobilizing effects of what is likely to be unfinished compost while maximizing aeration with no sacrifice in (or improved) water retention.

Al

Al,
Thanks for that explanation. Didn't realize that paper/cardboard would cause N immobilization! (Ya learn something enw every day!). I guess I'll work the paper into the next batch for future use.

Spag,
Yeah the soil is clay (masquerading as concrete) over here. I am lucky enough to have a neighbor who has a serious rototiller that I can borrow (I did the whole of my plot over the last few months where my raised vege beds will be).
The whole section was, at some time, "amended" by some lunitic with pea gravel to "break up" the clay. So in the last 6 months I have screened out about 3 cubic yards of this clay soil and the pea gravel and replaced it with 2 yards of year old horse manure (there was a water run-off issue near the hosue). Now I have put up 3 x 8'x4' raised vege beds (12" in height and dug down another 12" into the clay) and added another 1.5 yards of manure to those with the existing soil. I have then layered on some leaf/chips with a mixture of vege waste and some coffee grounds in a semi lasagna bed to rot over the winter.

So hopefully the vege department will be ready next spring.

The flower garden beds I have are a complicated mess. My wife wants a "cottage garden" which is damn close to impossible to create when you have a triangular shaped back yard with 15" brick beds to work with. I can't take the beds out as we rent so I am stuck with what I have. I have worked that soil (mainly with miracle gro type stuff) for the last 3 years and finally planted last spring with some vines to run along the fence and spaces for annuals and small shrubs to get a cottage feeling going.

I also took a chunk of grass out of the back corner and made a space for a couple of adirondack chairs for my wife. It's a funky triangle shape agaonst the beds and under the one big tree in the corner (no idea what the tree is). It's worked out well but I forgot when I laid the pavers up there that the roots from the big tree would expand and I will now have to rectify this next spring (still deciding how best to do that.

But all in all the "projects" have worked well so far and the wife is happy with her "retreat" so it was worth all the swearing and back breaking labor... :)

Your lunatic soil amenders sound like they went to the same school mine did. When we bought this house, the backyard was a big draw because it was nicely landscaped, with some built in planter boxes along the sides of the fence that were mostly empty. Fast forward to this summer when I decided to finally fill the boxes. I didn't get down 1" into the soil before I hit my first stone. Not as difficult to deal with as pea gravel by a long shot, but it was a smallish, smooth river rock-type stone. I chucked it aside, and kept digging... and hit another stone. Stone after stone needed to be pulled, purposely buried in the dirt, which I assume they did because they thought it'd help with drainage. I must have pulled about 100 lbs. of river rocks out of a 5 by 1 1/2 foot planter box. And all of the other boxes, along with the terrace, are all the same. A layer of soil on top of basically a load of rocks mixed in with the native clay soil. I've left most of the other ones alone because of this, lol.

Your wife is a lucky woman, that she has you to build her a garden retreat! I'd love to see pictures of all the hard work you've put in.

Spag,
yep, I figure it was these people trying to help with the drainage, or they thought it just looked nice to have pea gravel as their "toppng"... A french drain (which is really a roman drainage system that was used to build their roads) WILL work if you do it correctly, but it is more work than just throwing pea gravel on the dang "soil".

I haven't actually taken photos of the retreat as yet, but will do so when I have the last major planting in next spring.... The part I like most about it is that it cost less than $100 to do it all.... + about 50 gallons of sweat, and a torqued left knee when the dog decided to "help" while I was up a ladder installing the screws.

IF I ever work out how to add a photo to these forums I'll get a photo of the retreat for you.

btw. Making a really cheap soil screen is easy. 4 pieces of 2"x4" + some mesh. Cost is about $10.00. Then you just muddle your way thru a bed a week, throwing out the larger aggregate and any bad clay clumps. You can actually put that thru your green bin (I asked).

This was a good thread and I appreciated both @tapla (mid-Michigan, USDA z5b-6a) and @gardengal48 (PNW Z8/9) giving perspectives for raised bed soil based on seeking perfection versus seeking adequacy with the greatest simplicity. I think both approaches make sense depending on your project, and your personality.

@tapla (mid-Michigan, USDA z5b-6a) proposed a formula something like this:

1-1/4 yard of screened topsoil
1 yard of redwood compost
10 bags of floor dry
3-4 cu ft vermiculite
6 bags reed/sedge peat
10 lbs garden lime
5 lbs High-N slo-release turf fertilizer (like 27-3-3 or similar)
A micro-nutrient source like Micromax would be very helpful until the soil biota gets going

Assuming we were to substitute vermiculite with peat, and then express this as parts rather than as a specific volume, I think you could approximate this with:

1 part peat (12.5%)

3 parts compost (37.5%)

1 part Turface (12.5%)

3 parts topsoil (37.5%)

The organic and inorganic fractions are each 50%.

@tapla (mid-Michigan, USDA z5b-6a) is there some simple formula for how much garden lime, slow-release fertilizer, and micro-nutrient support you should add on a per-gallon basis for the mixed soil? So, for each gallon of soil you mix, how much of the other components get added? Anyone should be able to scale up from that.