Cinder Blocks - Double stack or Single?

My DH and I are planning on using cinder blocks for our SFG. But I'm in a bit of a quandry of what we should do when first starting out.

On the one hand - Double Stack means I can sit on the edge to "garden" and won't have to lean over or kneel much. Great thing because my knees aren't what they used to be!

Also, if we Double stack, we'll probably have to fill the bottom stack with sand, because filling 16" deep with MM would be expensive! But .. if we Single Stack, we'll be filling with 16" deep (total) anyway lol

On the other hand - Single stack means we get 2x the SF space! More room to plant stuff.

We are planning on doing quite a few 8' x 4' beds, over time, and I'm sure some will be double and some will be single, but just to get started, we have already acquired 40 blocks and I'd love to be able to get "something" layed out before the snow starts flying this year.

What would you do???

Also, since we're using cinder blocks, do we need to use mortar or just dry stack them?? Figure Boffer would know that one

Thanks in advance for your input and advice!

There is lots of info about table tops if you want to see them go to the top left side of page, put in table tops and put a check mark in the Search SFG Forum. I learned a lot from many of those discussions.

First I would consider your height standing or sitting. I want to stand so in my case I can offer this thought, that at 5'3" tall I'm thinking 30 inches high from the bottom of the blocks to the top of the 6 inches of Mel's Mix. Then consider the added height of the mature plants too. I would be bothered if everythingthing grew up and past my eyeball level and straight up over my head! I believe Boffer offers excellent advice of 36 inches tall just like a kitchen counter. But for my height I think I am going to lower the boxes a tad.

Oops I totally mis-read what you were saying, I thought you were using blocks and boxes. Sorry!

wncsohn wrote:Also, if we Double stack, we'll probably have to fill the bottom stack with sand, because filling 16" deep with MM would be expensive! But .. if we Single Stack, we'll be filling with 16" deep (total) anyway

I don't understand what the words in italics mean; what am I missing?

wncsohn wrote:What would you do???

I would make the boxes that I'd be planting first next spring. For me, that would be hardy cool crops. Like having a full wood shed or pantry, it's comforting to me to get my first boxes ready for spring planting now. Then, next spring, I can run out between rain showers to get seeds planted. No messing around making MM or making boxes when it's cold, windy, and wet.

wncsohn wrote:Also, since we're using cinder blocks, do we need to use mortar or just dry stack them??

Aesthetics is going to be the big influence here. The mortar you can see in a wall has little strength in it; it is used to get the blocks plumb, level, and square. The strength in a block wall comes from the re-bar and concrete that is in the holes of the blocks.

Laying the first coarse on the ground and dry stacking the second course is certainly practical for a gardening bed. It will be more 'casual' looking because the blocks are not all going to be level, and, there might be some movement from frost heaving. You can get lateral strength, cheap or free, by putting a stick or 1x2, about a foot long, into every other hole, then pack the hole with dirt or gravel that can be packed. Or, you could spend money to do it like a pro, by sticking ½ inch re-bar into every other hole and then filling the hole with concrete or mortar.

If your eye prefers the more formal and precise look of mortar bedded courses, then you would have to make a concrete footer to lay the first course on.

wncsohn wrote:My DH and I are planning on using cinder blocks for our SFG. But I'm in a bit of a quandry of what we should do when first starting out.

On the one hand - Double Stack means I can sit on the edge to "garden" and won't have to lean over or kneel much. Great thing because my knees aren't what they used to be!

Also, if we Double stack, we'll probably have to fill the bottom stack with sand, because filling 16" deep with MM would be expensive! But .. if we Single Stack, we'll be filling with 16" deep (total) anyway lol

On the other hand - Single stack means we get 2x the SF space! More room to plant stuff.

We are planning on doing quite a few 8' x 4' beds, over time, and I'm sure some will be double and some will be single, but just to get started, we have already acquired 40 blocks and I'd love to be able to get "something" layed out before the snow starts flying this year.

What would you do???

Also, since we're using cinder blocks, do we need to use mortar or just dry stack them?? Figure Boffer would know that one

Thanks in advance for your input and advice!

I'm not sure what you mean when you say when you single stack they will be 16" deep anyway. The blocks are 8" high each, so single level would be 8", double 16".



Here is pictures & info from when I built mine 2 blocks high:



https://squarefoot.forumotion.com/t5172-my-new-garden-and-helpers



It is a 4'x8' inside dimensions(outside it is 5'x9' as I used the narrower, cheaper, lighter 6x8x16 blocks). If I were going to redo it I would make that 4'x8'outside dimensions. It is difficult to reach some parts especially with the trellis(s) in place. I am very happy with the height. It is so easy to work on.



I put metal lath down to keep out gophers, then dry stacked the blocks in a staggered pattern (for more strength). I pounded in rebar thru the blocks or outside them in a few places to hold them in place. That was in february and it is holding well plus it will be fairly easy to change if I want to.



To fill I started with a couple of inches of dirt and manure, then put down several layers of paperwoven feed sacks as my weed barrior. I figure I probably ended up with 8-10" of MM with some extra compost thrown in.



I also used some leftover blocks for a small, single high squash bed. The squash quickly over took everthing so I did not have to get down there to weed or harvest:) so it worked fine. The squash are on a trellis.



I just scored a good deal on 3 old security doors to use as a base for my new beds. No gophers going thru them. Plus they are strong enough to be a base for a couple of table tops by putting them up on blocks.

Hmm.. guess what I said was confusing ... I thought by putting (total) in parenthases it would clarify I meant 2 single stack boxes at 8" depth each ... i.e. 16" total, lol

One 8' x 4' x 16" DOUBLE stacked bed with have either ...

1. 8" deep of sand & 8" deep of MM or
   
2. 16" deep of MM
   

Two 8' x 4' x 8" SINGLE stacked beds would both have 8" of MM (8" x 2 = 16")

Double stack would give ease of sitting to garden when needed.

Single stack would give 2x the gardening space.

Does that make a bit more sense? I'm not trying to be complicated! Seriously!


Either way, I'm hoping to get the bed(s) laid out before winter hits, and the MM into them. That way I can simply cover them with plastic to "overwinter" then have them ready and raring to go come spring!

Lindacol - cool! Looks like you dry stacked. Which is kinda what I want to do but DH ... ermm ... being who he is ... wanted to go all out with morter mix, re-bar .. the whole nine yards! Sometimes he likes to make things a whole lot more complicated than they need to be~! LOL

Boffer - I kinda was thinking about being able to plant an herb or two or some pretty flowers in the "holes" !! Maybe not every one of them, but at least a few! All those empty holes would bug me eventually.

I like the idea of just putting "sticks" in the holes and packing them really well with dirt (every other one). My Motto is "The easier the better"

I'm not so concerned about the boxes themselves being "visually pleasing". My concern is the produce I grow in them be "visually pleasing"! As well as "gastrically pleasing!!!" LOL

Re: "The Trellis" I had actually contemplated doing a 3' wide trellis, then skip two feet and do another 3' wide trellis. That way it would be easier to get into the "center" of the back side of the garden. Also, some plants (i.e. watermelon, etc) require (basically) 2 SF spots, so I thought I could plant those on that inner 2' "space" ... darn ... describing things without pictures is so difficult sometimes, lol. i.e. leave that center 2' space empty.

X X X E E X X X
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Okay, before I complicate things even more I'm gonna close out this post, lol. Might add some later in another post!

wncsohn wrote:...Which is kinda what I want to do but DH ... ermm ... being who he is ... wanted to go all out with morter mix, re-bar .. the whole nine yards! Sometimes he likes to make things a whole lot more complicated than they need to be~! LOL...

A good compromise would be to dry stack and then parge the wall. That would give it a stucco-like look; you wouldn't know it was cinder blocks.

This guy dry stacked a 2100 square foot house; then used nylon netting from the fabric store and a mortar blend to cover the sides of the house for strength and appearance. Minimal cost; mucho perspiration!
http://www.texasmusicforge.com/gimmeshelter1.html

wncsohn wrote:...I kinda was thinking about being able to plant an herb or two or some pretty flowers in the "holes" !! Maybe not every one of them, but at least a few! All those empty holes would bug me eventually...

I was going to suggest that, but they would get in the way of sitting! In the empty holes, you can stuff the first coarse of blocks with newspapers so you don't need as much MM to fill up the top coarse. I use cinder blocks to outline a raised bed; I've planted beets, radishes, onions, marigolds, and various lettuces in the holes. They do just fine.

wncsohn wrote:Lindacol - cool! Looks like you dry stacked. Which is kinda what I want to do but DH ... ermm ... being who he is ... wanted to go all out with morter mix, re-bar .. the whole nine yards! Sometimes he likes to make things a whole lot more complicated than they need to be~! LOL

Boffer - I kinda was thinking about being able to plant an herb or two or some pretty flowers in the "holes" !! Maybe not every one of them, but at least a few! All those empty holes would bug me eventually.

I like the idea of just putting "sticks" in the holes and packing them really well with dirt (every other one). My Motto is "The easier the better"

I'm not so concerned about the boxes themselves being "visually pleasing". My concern is the produce I grow in them be "visually pleasing"! As well as "gastrically pleasing!!!" LOL

Re: "The Trellis" I had actually contemplated doing a 3' wide trellis, then skip two feet and do another 3' wide trellis. That way it would be easier to get into the "center" of the back side of the garden. Also, some plants (i.e. watermelon, etc) require (basically) 2 SF spots, so I thought I could plant those on that inner 2' "space" ... darn ... describing things without pictures is so difficult sometimes, lol. i.e. leave that center 2' space empty.

!

Yes mine are dry stacked - it was easiest to do and easiest to cange if/when I change my mind. Be sure you take into acount the width of the blocks like I mentioned before. My bed is too wide so I might change that in the future If it was all cemented in that would not be possible.



I also tried planting some of the holes in the blocks and found it to be a PIA. I have drip watering set up for the bed and never got around to arranging it for the plants in the holes so most of them died.



I'm not sure I understand what you mean by 3' wide trellises. But if you have them across the bed then you will have trouble reaching the tops in the middle.

After much debating over many different things, I'm going with a single-stack, dry fitted cinder blocks. Basically, this is the cheapest method of making a SFG bed that won't ever rot, decay, float away or any other disaster that can happen to a SFG bed. It will take a bit of work to make it all level, but after I'm done with that, it should be great. After the blocks are laid down and the Mel's Mix is put in, I'll probably get some cap stones for the top too. Though I may just plant some ornamentals in the holes...I've not yet decided on that(or mint, or something else that can be invasive). Painting the blocks is also an alternative to the utilitarian gray.

I did think about running 2 courses of blocks, but that being 16" tall seemed a bit too much, when I can set the blocks ~2" in the ground and have 6" above the ground...seems perfect to me. That will also(hopefully) stop the grass from growing into my beds later.

The great thing with concrete blocks is their dimensions of 8"x16"x8". A 4'x4' box only needs 10 blocks and would cost about $15. The only other item that comes even close to that is untreated "white wood" lumber that will begin decaying the second you put it down and fill it up.

I don't think the math is right there...

I think 10 blocks will get the OUTSIDE dimensions to 4'x4', but you'd need at least 12 blocks (with open corners) or 14 blocks to get 16 squares INSIDE the blocks. I can post a pic later, but maybe I'm just confused.

+1

Thanks gwennifer, you were succinct. I couldn't figure out how to say it without pictures.

Unmutual wrote:
The great thing with concrete blocks is their dimensions of 8"x16"x8". A 4'x4' box only needs 10 blocks and would cost about $15. The only other item that comes even close to that is untreated "white wood" lumber that will begin decaying the second you put it down and fill it up.

OK, to confuse the issue...
You might need 12 or 8 or 16 but under no circumstances would a 4X4 box need 10 simply because it does not divide evenly by 4 (the number of sides on the box.)
Twelve would be correct (16" * 3 blocks = 48 inches of blocks; 4 sides * 3 blocks = 12 blocks)

And remember, all the pressure will be in the box, so the blocks need to be secured. However, a stake either in the blocks or on the outside will do the trick.

Doh! Yes, you're right...14. For some reason I didn't count one of the long walls(probably because I only made 3 walls, checked the inside measurements and ran with it). This would raise the cost to $20, still cheap for a rot resistant 4'x4' bed. At least I was correct there :p