Raised Bed Garden

Maylith says Very cold, hard rain here in Virginia, and our lawn already needs mowing (aside from the salt-killed portion that is!) Anyone here tried to put in a cottage stone retaining wall? I can't decide if I'm ambitious or insane....

Lometa says raised bed gardening is a good way raise veggies.

GrouchyOldMan says, Building a proper stone wall is a big undertaking, so you should first decide if you want to be a stonemason or a gardener this spring. I'd suggest knocking together some wooden raised beds out of treated 2x12. Feed it with a drip irrigation system and you'll be all set.

- Chatter in the E2 Greenfingers Group

An easy and inexpensive vegetable or flower garden you can build

Raised bed gardening avoids many of the problems and headaches associated with the average small garden by growing plants in long narrow boxes of soil above the ground.  Here are some of the primary advantages:

  • Raised bed gardens are typically long and narrow so you can walk all the way around them without compacting the soil
  • They are very space efficient so you can fit them into almost any growing space, 
  • Because you don't need room to walk in the garden, you can space the plants closer together without crowding them, resulting in a greater yield,  
  • They have excellent drainage allowing the plants to "breathe," and allow you to control the water and fertilizer efficiently,
  • Extended growing season; raised beds warm up quicker in the spring and last longer into the fall,
  • Many garden pests, such as gophers, are unable to plunder raised bed gardens,
  • Because you don't have to bend over so far to reach the plants, they are significantly more comfortable for grouchy old gardeners like me to work in. 

Below you'll find plans for constructing a simple raised bed garden planter suitable for most anything that will grow in your local climate.  I've used these for a wide variety of vegetables and herbs, and they should be equally capable of hosting any variety of bulbs or flowers.  There are countless "how-to" plans available for similar raised-bed garden projects, and the primary advantage of this particular one is that it's inexpensive and easy to build and in the twenty-odd years I've been using it, I've never had a problem adapting it to the available terrain.

The basic unit of the raised bed garden is an eight foot long by two foot wide  box, standing one foot tall (2.4 meter x 0.6 meter x 0.3 meter) with screen on the bottom to keep the critters out and a simple drip system irrigation system to reduce watering and allow you to feed your plants conveniently.  The system is modular, so if you have more room you can just add another bed without much fuss.  The beds are made of treated lumber, so they last virtually forever and they are cheap to build in the first place, so you can even justify using them when you're a temporary resident on a strict budget.  I used to brag that you could pay for them with one good summer's harvest of veggies.

So that's the premise and the steps below will lead you directly to it.  I'm using a cookbook format for convenience but, obviously, you can and should improvise as needed to fit your local needs, resources and inclinations.

Materials List

2"x12"x8' treated lumber: 2 pieces.  

2"x12"x2' treated lumber: 2 pieces.  

This wood forms the sides and ends of the box.  The long pieces are standard lengths but the shorter end pieces will probably need to be cut out of a longer length of lumber.  Most lumberyards will do custom cuts for you for a nominal fee and, unless you have a good saw and a steady eye, it's probably worthwhile to have them do it for you.  You might try asking for one eight footer and one twelve footer with the two two-foot pieces cut off one end.   I make my boxes out of a twenty footer length of 2 by 12 cut at three places (cut at: 2-feet, 4-feet and 12-feet), to make the four boards. 

Don't use untreated wood as it will rot out after a couple of years.  Studies have shown that treated wood1  won't harm your plants and that it doesn't transfer any of its nasty chemistry into the vegetables grown around it. Depending on where you live, the "treatment" used on "treated" wood may be the older arsenic-based process, or the newer, environmentally friendly, copper-based products.  Regardless of which you use, remember to wash your hands after handling it.

2' x 8'-6" galvanized hardware cloth screening (1/4" mesh): 1 piece.  

This metal screen will keep moles and gophers from burrowing into your garden from below.  The typical mesh size for hardware cloth is 1/4" which is big enough to let roots squeeze through, but keeps the critters out. Our raised bed garden is only two feet wide, so this piece will cover the entire bottom.

Simpson Strong-Tie A34 angle brackets: 8 pieces

Welcome to the world of pre-engineered connectors!2  These little metal widgets come in an abundant array of shapes and sizes and are used to replace or enhance traditional nailing for the floors, walls and ceilings of wooden houses.  As a group, they have virtually revolutionized modern house construction, reducing construction time and cost while creating much stronger buildings.  Even a brief overview of their history and modern usage is beyond the scope of this discussion, but the reader is encouraged to peruse the Simpson website at their leisure.  The Simpson A34 is a small, galvanized, metal plate formed into a 90 degree angle with holes for nails and a "Speed Prong" shaped like a little nail that is used to temporarily hold the bracket in place before nailing.  

In this project, we'll use the Simpson A34 Tie Plates to hold the raised bed garden frame together so securely that you could literally drive a tractor over it without breaking the box. Embarrassingly, I can attest to that claim personally: 'friends don't let friends drink and garden.'  

Simpson Strong-Tie N8 nails: Box of 100

These stubby nails are designed for the A34 brackets and are the easiest things in the world to use because they don't bend.  You're going to be hammering in a bunch of them, so these are worth a few bucks more.

Drip System Irrigation 

This part is entirely optional, and probably not justified for a single raised bed box, but if you're feeling ambitious and want to impress your gardening buddies, you can easily add a simple drip irrigation system to the project for some pocket change and a couple of hours of work.  Maybe it's a grouchy old guy thing, but I get totally jazzed every time the automatic timer for my drip system clicks on and I hear the flood of water rushing through the pipes.  It's like having a gardening robot to do my work for me.  The drip system information in the Apple Orchard writeup is easily adaptable for this project and includes technical info, construction tips and purchasing sources. 

Compost, peat moss and potting soil

Each raised bed box will nominally hold 16 cubic feet of soil.  You can fill this space using any soil type that meets your needs and either amend it or replace it each season as you choose.  If you are an experienced gardener, you probably already have a good idea of what soil composition will best suit your intended use, but here's a good starting point based on materials you can purchase at any garden center.  

The ideal vegetable garden soil is a deep, loose, well drained, loam with significant organic matter content. Towards that end I'd suggest using one part peat moss, two parts compost and three parts potting soil as a good general purpose mixture.  Each of these components is available in bags of varying sizes, so you can purchase what you need to fill as many raised beds as you intend to build. For more information on soil types, see the excellent Simple ways to test your soil writeup on the subject by karma debt.

Construction

This project is designed to be completed by a complete novice, and it's been tested on my teenaged daughter, who is in fact a complete novice.  The only skill you'll need is swatting nails with a hammer, and that's a skill that tolerates a wide range of expertise.  By the end of the first box you'll be be so good at this that you'll want to make a second one just for fun.  Trust me on this.

1. Lay out the boards. Hopefully you talked the lumberyard into cutting your boards for you, so they're ready for assembly.  If not, get it done now.  Our starting point is four boards: two end pieces and two side pieces.  Lay these out on a hard, flat surface so that they are standing on edge and the long side pieces fit inside the shorter end pieces.  I'm wretched at ASCII art, but it should look something like this:
---------------------------------------
|              End Piece              |
---------------------------------------
|     |A                       B|     |
|     |                         |     |
|     |                         |     |
|  S  |                         |  S  |
|  I  |                         |  I  |
|  D  |                         |  D  |
|  E  |                         |  E  |
|     |                         |     |
|     |                         |     |
|     |                         |     |
|     |                         |     |
|     |                         |     |
|     |                         |     |
|     |                         |     |
|     |                         |     |
|     |                         |     |
|     |                         |     |
|     |                         |     |
|     |C                       D|     |
---------------------------------------
|              End Piece              |
---------------------------------------

The outside dimensions of the box should be two feet wide and eight foot - three inches long. Admire the box for a few minutes, to get the configuration clearly in your head before continuing.  If you have a tape measure check the dimensions.  Breathe deeply, savor the moment.

2. Take a pencil and scribe a line on the inside of the End Pieces where the Side Pieces connect.  These points are marked "A", "B", "C", and "D" in the drawing above. You want a nice dark pencil line running the whole width of the end piece.  We'll use these to guide the nailing in the step below.

3. Lay the end pieces flat on the ground and position the eight A34 brackets on them so that the "Speed Prong" on each A34 points down at the end piece and the bend lies along your pencil line.  Since you're using two brackets per corner, position each of them about two inches in from the top and bottom of the end piece.  Here's more bad ASCII art to illustrate:

 

               (End View)         
     |                           | 
     |                           | 
     |                           | 
     |____\____          ____\___| 
-----^---------------------------^------
|              End Piece               |
----------------------------------------
4. Tap the Speed Prongs into the end pieces with your hammer to temporarily position the brackets along the line, then hammer four of the N8 nails into the round holes. Repeat this to nail all eight A34's to the two end pieces.

5. Flop one of the side pieces over and position each end piece over it for nailing as shown below: 

------                            ------
| E  |                            |  E |
| N  |                            |  N |
| D  |                            |  D |
|    |                            |    |
|    |         (End View)         |    |
|    ||                          ||    |
|    ||                          ||    |
|    |/                          \|    |
|    ||_________         ________||    |
|    |----------/-----------/-----|    |
|    |          /Side Piece /     |    |
|    |          /           /     |    |
----------------/-----------/-----------

6. Repeat step 5 with the other side piece to complete the box.

7. Lay the hardware cloth (screen) over one side of the box so that it's evenly positioned along the sides and extends about three inches beyond each end.  Use more of the N8 nails to secure it to the box.  Fold the overlapping ends up the end pieces and nail the excess screen to the end piece.

8. Turn the box over so that the screen is on the bottom and position the box where you want it.  Be sure it's in the right place because it will be too heavy to move again. The optimal orientation3 for the boxes is generally along a Southeast, Northwest axis, allowing all your plants to receive the maximum sunlight, so consider that where possible. If you have more than one box, put taller plants, like corn, in the more northerly boxes so they don't shade the little guys.  Spread a layer or two of newspaper along the bottom to keep the soil from eroding during the first few waterings, then add the soil components until you've filled the box.  Compact it by stepping lightly down the length of the box, then fill it to the top again

9. If you've decided to add a drip system to your raised bed, now's the time to install the drip tubes.

10. Saturate the soil with water and let it drain over night before planting, then get those plants plugged into that rich moist loam and stand back!

 

We must cultivate our garden...
- Voltaire, Candide

===================&===================

1  Treated wood information: http://www.treatedwood.com/
2  Simpson engineered connectors: http://www.strongtie.com/products/connectors/ltp4-ltp5-a34-a35.html
3  Primer on Raised Bed Gardening: http://ohioline.osu.edu/hyg-fact/1000/1641.html

--Special thanks to the E2 Greenfingers group for their helpful comments and suggestions.