Building raised beds with the SFG method

[Agilityscots]

Hi everyone,

I hope you're not all sick of my questions yet. This is the only place I can ask questions of so many experienced people!

My husband and I are getting ready to build our beds for our first garden; we're planning on using the Square Foot Gardening method, including the mix for soil that the author recommends (1/3 peat moss, 1/3 vermiculite, 1/3 compost). Has anyone here used this mix? Anyone have success with it before I sink a bunch of money into the ingredients? If someone hasn't had success, I need to hear it, fast! Any other suggestions for materials to fill the beds with would be greatly appreciated.

Amy

[dcarch]

Originally posted by Agilityscots:

Hi everyone,
I hope you're not all sick of my questions yet. This is the only place I can ask questions of so many experienced people!
My husband and I are getting ready to build our beds for our first garden; -----Amy

We are all here to learn.

For my raised bed, I use just soil, leaves from trees, and lots of kitchen crap (600 gallons over the years!).

I don't compost much, just direct burial, because I am lazy. Normally, it is a very good idea to compost first.

Things have been working out fine for me.

dcarch

[Agilityscots]

Thanks for the response, dcarch! Our soil is heavy clay, so it's out...unless I want to spend weeks doing backbreaking labor. I need to put something else, or a mix of something else, into our beds.

We have been composting (kitchen scraps and chicken litter from my hens) since last summer, but I don't think it's rotted enough to use this spring. I think I'm stuck buying it. I should be able to use my compost by the fall, though.

Amy

[dcarch]

BTW, re. kitchen scraps:

I have a separate bucket in the basement with an air-tight cover to accumulate. Every 4 to 5 days, the bucket will be full and I will then bury the contains. By that time, the scaps are rotting and really stinky to high heaven. I have never had any problems of animals digging up the scraps.

dcarch

[Agilityscots]

Originally posted by dcarch:

BTW, re. kitchen scraps:

I have a separate bucket in the basement with an air-tight cover to accumulate. Every 4 to 5 days, the bucket will be full and I will then bury the contains. By that time, the scaps are rotting and really stinky to high heaven. I have never had any problems of animals digging up the scraps.

dcarch

I do something similar...I keep a container in the fridge (I got SO tired of fruit flies, no more containers in the kitchen), and when it's full, I put it in my compost tumbler. After a week to a month, when the tumbler is full, I dump it into the 4x4 pile. I think the bottom half of my pile may be rotted enough, but getting to it is another matter! ha ha

Amy

[dcarch]

Originally posted by Agilityscots:

I do something similar...I keep a container in the fridge (I got SO tired of fruit flies, no more containers in the kitchen), -----Amy

Amy,

I have been there. No scraps in my frig because it uses electric energy.

Here is what I have done:

1. Get a piece of plate glass,
2. tape a few sheets of sandpaper on the glass,
3. rub and grind your container opening on the sandpaper until the edge is flat as the glass,
4. The glass will be completely flat and air-tight as the cover for the container, no smell or fruit flies can get in or out and there is no smell in the kitchen. So convinient on the ketchen counter next to the sink and chopping board.

dcarch

[Bill]

Amy,

If you're building new raised bed atop hard clay soil, you first need to strip off the top layer of vegetation if you want to start now. If you are going to prepare and build the bed in warmer, drier weather, it's a different process. But since you indicate immediacy, you need to strip off the grass sod or whatever surface vegetation is there now.

Then till up the underlying clay soil to at least an 8-inch depth to loosen the compaction. The next step would be incorporating at least 2 - 5% well-composted organic matter into the tilled clay soil. You can estimate the cubic foot quantity of organic matter needed by determining the square footage of your raised bed outline and multiplying that by .7 for 8-inch tilled depth, .75 for 9-inch tilled depth, whatever, then multiplying the resulting cubic feet of tilled clay soil by .02, .05 or whatever percentage you're shooting for.

Organic matter is the best amendment for improving drainage in clay soils. Period. Not sand. OG will combine with clay particles to facilitate better drainage and better retention of nutrients than will sand. Why till up and incorporate OG into the native clay soil underlying your raised bed? Well, because if you don't, you are simply laying a layer of good, well drained garden medium atop a slab of concrete that will act as a fragipan horizon and bench water in the bottom several inches of your raised bed, drowing the root system of your plants.

Following the improvement of the clay soil under your raised bed, construct the side boards to the height you've chosen and begin filling the bed in "lifts" or shallow layers of the growing medium you've mixed. Each time you put in say a 6-inch lift, till that into the underlying layer. When you get the bed fully filled, you should have a relatively homogenized bed of growing medium ... or at least a bed where the growing medium is gradually denser from top to bottom as it would be in Nature.

Do not compost your kitchen waste in your garden bed. While that may be suitable for some folks, it also attracts pests like mice, voles, rats, skunks, racoons, etc. Additionally, compost should be rotted in a heap so the interior temperature is raised to a level that pasturizes the mix. The heap should be turned every so often so that the cooler material near the surface of the pile comes in contact with the heat of the interior and the interior is continually fed new micro-organisms required to complete the rot. This cannot happen efficiently when you toss kitchen wastes willy-nilly into a shallow garden bed that is subject to a subsurface frost line.

You indicate "economy" in your initial post. And yes, vermiculite and peat moss is expensive when you get into building extensive raised beds ... particularly vermiculite if you're mixing it in at 33.3% of the growing medium. I'm lucky ... there is a farmer nearby who has a soil-building business and sells various of his custom mixes for 25 bucks a pick-up load. He builds them out of rotted horse bedding, manure, native clay, sand, lime, and rotted bark fines. Professional nurseries always have their own nursery mixes. You might try one of the more well-drained mixes. I can get a great nursery mix here from Combs Nursery for 35 bucks a pick-up load.

Don't buy "topsoil." It's a pure-D rip-off. Don't want to go into it right now, but no one is selling true topsoil. There are no laws that give a definition of topsoil, and most of what you would get is river bottom dredgings or sewer department compost, etc. Nuff said.

Bill

[Agilityscots]

Bill, thank you for your excellent response!

The plan laid out in the SFG book is to build the frame for the bed, line it with several layers of weed cloth, and simply start filling with the mix that the author recommends. He does not indicate that it's necessary to tinker with the soil underneath the box, but the way you explain it sure makes a lot more sense. So, just to make sure, you think this is a bad idea for drainage? I am so happy you responded, because you mention several things that a new gardener like me wouldn't know...until it might be too late.

Several people on my chicken message board have said they used Miracle Gro organic garden soil, which sure seems a lot easier than mixing up all this stuff. But you think an even better bet might be a nursery mix?

I do know that my compost isn't yet well rotted and I won't be able to use it this season. So at least I got that part right!

Oh, and I don't know if immediacy is necessarily a concern, either; I want to be ready to plant lettuces, spinach and peas by mid-April. Do I have enough time to do what I need to do?

Amy

[Agilityscots]

Originally posted by dcarch:

Amy,

I have been there. No scraps in my frig because it uses electric energy.

Here is what I have done:

1. Get a piece of plate glass,
2. tape a few sheets of sandpaper on the glass,
3. rub and grind your container opening on the sandpaper until the edge is flat as the glass,
4. The glass will be completely flat and air-tight as the cover for the container, no smell or fruit flies can get in or out and there is no smell in the kitchen. So convinient on the ketchen counter next to the sink and chopping board.

dcarch

Great idea! Now if I can get my darling husband to do this for me...

Amy

[Bill]

Amy,

It would surprise me greatly if your soil condition in Ohio (I'm assuming central Ohio with the Z5/6 indication) is ready to till. Surely it's too wet and soggy, if still not frozen underneath. If you're dead set on lettuce and spinach set in early (can you plant spinach that early in 5/6?), you might do as recommended in this book you mention as those two crops probably can get by in a small, shallow bed. Peas ... hmmm ... I've planted them in mud in late Feb-early March before. I don't know ... how many pea vines you talkin' 'bout?

Maybe you should build one small temporary bed for these early projects. And then when the soil dries sufficiently, you can build some much better permanent beds as described with tilling of the underlying soil. My suggestions for the raised bed procedure come from the Purdue Extension Master Gardeners Program, and are proven reliable and workable.

As far as growing media to fill your beds, again, I was offering suggestions based on your first inclination toward economy. So, yes, I would get on the horn right now and call around and find out what a local nursery or local soils builder has to offer. Call some local greenhouses and ask them for recommendations or leads to local producers of landscape mixes. Tell them what you're growing, 'cause most of my focus is on tomatoes, peppers and cukes, so I go for well drained, high OG content mixes that are mostly composted manure, bark chips, bark fines, leaf mould, etc. mixed with sand, clay, and lime. For sure, the mix you first indicated is a great mix ... for seed starting, and small or limited numbers of containers ... but for me it would be way too expensive for a raised bed. I even fill my tomato and pepper containers with the rougher mixes I mentioned above.

For a new raised bed built later in spring or early summer, the standard practice is outlining the perimeter for the bed with spray paint or a salvage garden hose, spray the turf with Roundup, wait 'til the vegetation is dry and brittle, roto-till to a depth of 8 - 12 inches, and proceed as described in my first posted message. I would recommend sideboard height of 12 - 18 inches and the use of 2-by lumber which has not been treated with arsenic-based preservatives, concrete blocks, decorative stone, or some other material that will not leach contaminants into your growing media.

Other considerations are ample and appropriate mulching materials for hot Midwestern summertime weather and drip irrigation hoses or drip tape for irrigation as raised beds drain or evaporate moisture quicker than grade-level, native soil gardens. Mulch should be 2 - 3 inches thick. Composted bark chips are cheap and good. Rotted leaf mulch is great as is composted grass clippings. Wheat straw is fine too. Don't use hay ... too many weed seeds.

Bill

[dcarch]

Originally posted by Agilityscots:

Great idea! Now if I can get my darling husband to do this for me...

Amy

You want me to find the link to Victoria's Secrete?
Get a few things there to put on. He will do anything !

dcarch

[Agilityscots]

Originally posted by Bill:

Amy,

It would surprise me greatly if your soil condition in Ohio (I'm assuming central Ohio with the Z5/6 indication) is ready to till. Surely it's too wet and soggy, if still not frozen underneath. If you're dead set on lettuce and spinach set in early (can you plant spinach that early in 5/6?), you might do as recommended in this book you mention as those two crops probably can get by in a small, shallow bed. Peas ... hmmm ... I've planted them in mud in late Feb-early March before. I don't know ... how many pea vines you talkin' 'bout?

Hi Bill!

Oh no, I wasn't ready to start tilling now. Our ground is still frozen solid. But I'm a planner by nature, and I want to make sure I'm not rushing around building beds when I have plants that need to get into the ground. And as far as spinach and lettuce, I've read that they should be put in about a month before the last frost date...which, here, is 5/15. So I thought I was doing it as I should??

Pea vines: probably 2.

Maybe you should build one small temporary bed for these early projects. And then when the soil dries sufficiently, you can build some much better permanent beds as described with tilling of the underlying soil. My suggestions for the raised bed procedure come from the Purdue Extension Master Gardeners Program, and are proven reliable and workable.

Sounds good to me!

As far as growing media to fill your beds, again, I was offering suggestions based on your first inclination toward economy. So, yes, I would get on the horn right now and call around and find out what a local nursery or local soils builder has to offer. Call some local greenhouses and ask them for recommendations or leads to local producers of landscape mixes. Tell them what you're growing, 'cause most of my focus is on tomatoes, peppers and cukes, so I go for well drained, high OG content mixes that are mostly composted manure, bark chips, bark fines, leaf mould, etc. mixed with sand, clay, and lime. For sure, the mix you first indicated is a great mix ... for seed starting, and small or limited numbers of containers ... but for me it would be way too expensive for a raised bed. I even fill my tomato and pepper containers with the rougher mixes I mentioned above.

Okay, that makes a LOT of sense. I'm definitely going to start calling around and see what kind of soil they have to offer (thanks for the tip on "topsoil"!). My bed will be small--only 4x8. I want to start small and simple rather than going nuts and building a bunch of beds the first year I try this. I'm not so much into economy as I am doing it right and doing it small this first year.

For a new raised bed built later in spring or early summer, the standard practice is outlining the perimeter for the bed with spray paint or a salvage garden hose, spray the turf with Roundup, wait 'til the vegetation is dry and brittle, roto-till to a depth of 8 - 12 inches, and proceed as described in my first posted message. I would recommend sideboard height of 12 - 18 inches and the use of 2-by lumber which has not been treated with arsenic-based preservatives, concrete blocks, decorative stone, or some other material that will not leach contaminants into your growing media.

Duly noted. Thank you! Quick question: I use no chemicals on my lawn or flower beds for multiple reasons. Any suggestions for clearing the grass that don't involve chemicals?

Other considerations are ample and appropriate mulching materials for hot Midwestern summertime weather and drip irrigation hoses or drip tape for irrigation as raised beds drain or evaporate moisture quicker than grade-level, native soil gardens. Mulch should be 2 - 3 inches thick. Composted bark chips are cheap and good. Rotted leaf mulch is great as is composted grass clippings. Wheat straw is fine too. Don't use hay ... too many weed seeds.

Bill

Ooooh, mulch...hadn't even thought of that. Duly noted once again, added to list of notes...

Bill, you're invaluable! Thank you!

Amy

[Agilityscots]

Originally posted by dcarch:

You want me to find the link to Victoria's Secrete?
Get a few things there to put on. He will do anything !

dcarch

Aw geez...you men are all the same!!!

Amy

[dcarch]

Here it is.
No flies.
No smell.
No frig.

dcarch

[Agilityscots]

I like it! Straightforward, and no stink and no bugs. Definitely have to set the hubby onto this...

Amy