Introduction: Building a Raised Garden Into a Hillside.
I have a small backyard with very little level ground and plenty of shade. I wanted to expand my garden, but the prime real-estate was up a six foot incline to my back fence. It took a lot of digging and what seemed like endless root cutting from a former maple tree to tame this hillside. I ended up with: four 4x8 beds, one 8x8 bed, four 2x4 beds and some additional areas for shade plants at the top.
Per 4x8 bed
6 4x3/4''x8' (pressure treated fence boards)
1 cu yds of generic garden soil
1/2 bag sphagnum peat moss
2 bags compost manure
2 bags quality garden soil (miracle grow, etc.)
Step 1: Building the Frames
I decided to make the first beds using mortise and tenon joints because I liked the look. It looks similar to a bed frame when assembled. I used my router with a guide attached and a 3/4'' spiral cut bit. This made the 3/4'' side fit tightly in the mortises. I made several passes, gradually plunging deeper each time to achieve the desired depth of the mortise to prevent overheating the bit.
Dry fit everything to make sure you haven't made any mistakes before digging your footings. Because these beds are set into a hillside, it is best to anchor your 4x4 posts in the ground.
Tip: Make a Story Stick to mark the position of every cut and mortise. Use your Story Stick to mark each board, rather than your tape measure. This makes marking your wood much faster and will ensure uniform cuts on each piece.
Step 2: Filling With Soil.
Once your beds are in place and you are happy with your alignment, you can begin filling them with soil. It is also recommended that you add a layer of mesh wire to the bottom to prevent unwanted guest from digging up into your beds. It will take about 1.25 cu yds of soil to fill a typical 4x8x1 bed. I ordered 5 cu yds of garden soil from a local nursery to start my beds off. I then added a layer of sphagnum peat moss, 2 bags of compost manure and 2 bags of quality vegetable garden soil to each 4x8 bed. I worked everything into the soil before planting.
I used left over stones from our patio to build the steps. They ended up looking pretty good and it didn't cost me anything!
Step 3: Planting
I began most of my garden from seeds. I then transplanted everything to other beds. It is critical to follow the advice for spacing. Some plants like squash get very large and will shade out plants that are too close. After your first season, you will get the hang of this. But in general, pay attention to how the sunlight tracks across your yard for the entire day. Plant taller plants, like tomatoes and corn in the back to prevent them from shading shorter plants like strawberries and peppers.
Some plants grow well together. A Three Sisters Garden has corn, beans and squash. The beans use the corn stalks as support and the squash shades out weeds.
Keep your garden watered, but not over watered. I attached two brass sprinklers to metal stakes and put them on an inexpensive digital timer. Everything gets watered about 1/2'' every two days this way.
Step 4: This Year's Addition Complete.
Now it's time to sit back, relax and enjoy your bounty. Yeh right, you better get started pulling those weeds now!
In hind sight, I don't know that mortise and tenon joints were the best choice because they could cause the wood to rot a little more quickly. Time will tell.... but they look great!
Step 5: Harvest Time
I decided to add some pics here as I harvest during the summer.