Build a Raised Bed for Alpines and Rock Garden Plants

Wild Ginger Farm

Reasons to build a raised bed

for alpines and rock garden plants

* Raised beds can be built in just about any available space, large or small;

* The soil in a raised bed can be easily adapted to meet the needs of the plants;

* Raised beds are easier to tend than ground level gardens;

* Plants are easy to view and study in a raised bed;

* If desired, a removable roof structure to protect from winter wet can be built above a raised bed.

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How to build a raised bed for alpines and rock garden plants

STEP ONE - Select a location and decide on the size of your raised bed

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We chose an unused area in front of our hoop house to build a raised bed. The outside dimensions of the finished bed are 6' wide by 8' long, but just about any shape and size would work. We made sure there was enough room for an access path on all sides. We decided to use concrete blocks to create a sturdy structure. We leveled the ground under the blocks and alternated each layer for strength. We pounded rebar into each block cavity and packed it with roadbed rocks. We could also have filled the cavities with concrete. Other materials including brick, railroad ties or large rocks could have been used to create the raised bed.

(Optional) Apply a Finish to the Surface

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We chose to stucco the sides and top to create a place to sit and enjoy the plants! Truls put on two coats of stucco, the undercoat and later a colored finish coat. Other options included facing the blocks with stone, capping the top with pavers, or leaving it as is.

STEP TWO - Fill the bed with soil mixture

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We will grow alpines and other small rock garden plants in this raised bed so we wanted a lean, very well-drained mix. Using equal parts sand and grit and some compost, we combined the mixture with our small tiller. Raised beds can be used to grow a wide variety of plants and the bed could have been filled with native soil and amendments to create a well-drained planting soil.

STEP THREE-Select the rocks

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We went to the local rock yard and selected these plutonic rocks. They have a weathered appearance we found appealing and came in a variety of sizes and shapes. Learning from past experience, we got more rocks than we expected to use and planned to put any extras in the nearby herb bed. By using the same rocks in a nearby space, we created continuity between the raised bed and the rest of the garden.

STEP FOUR - Place the rocks.

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Now came the fun part, positioning the rocks! We started at the edges and worked our way up, using rocks to stablilize the soil on the steepest slopes.

We established natural looking contours by varying the distances between rocks and creating planting basins and nooks. We buried the rocks by varying amounts. Some rocks were placed close together to create planting crevices. Positioning some rocks upright created drama.

Once we were satisfied with the placement of our rocks, we wet the raised bed thoroughly to allow the soil and rocks to settle.

STEP FIVE- Planting time!

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We selected our plants, keeping in mind the small scale of the space. Even with careful selection, some plants will likely outgrow the bed eventually and need to be relocated. We may also need to fill in areas with additional plantings if the current plantings do not fill in as anticipated.

In placing the plants, we considered the slopes and orientations within the bed that create micro-climates. South and west slopes were planted with the most heat tolerant selections while north and east slopes were used for plants that appreciate some protection from the heat of the day. The entire bed was topdressed with grit following planting.

Plants included in the initial planting were Dianthus subacaulis, Heuchera pulchella, Dianthus glacialis, Antennaria dioica, Schivereckia doerfleri, Lewisia cotyledon, Gentiana spetemfida v lagodochiana, Silene acaulis, Androsace carnea, Linum flavum 'Compactum', Hymenoxys grandiflorum, Festuca scoparia, Petrophytum caespitosum, Androsace septentrionalis, Soldanella alpina, Rhodiola rhodantha, Androsacce sarmentosa, Gentiana gracilipes, Ranunculus graminius, Arenaria ledebouriana, Anacyclus pyrethrum v depressus, Raoulia subsericea, Chaenorhinum origanifolium,

UPDATE

This photo shows the raised bed the first spring.

Almost every plant has thrived and put on spring show!

Examples of Other Types of Rock Gardens

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