Flat planting terraces have been known for many millennia from a wide variety of cultures and parts of the world: just think of the Hanging Gardens of Babylon to the rice terraces in Asia. Staircase raised beds are an effective measure to prevent soil erosion on steep slopes, to make sensible use of rainwater runoff and to create flat planting areas.
What are the advantages of stair raised beds?
Staircase raised beds are staggered beds that are arranged downhill like steps. They offer security, easier care and expand the planting area. The bed height is ideally 50 cm (sitting) or 80-90 cm (standing) and a planted bed depth of max. 70 cm is optimal.
What are stair raised beds?
Staircase raised beds are beds that are staggered one behind the other like steps. They can be cared for while standing or sitting. The plant stairs offer a whole range of advantages: The brick support structures secure the slope, the flat beds increase the planting area and - last but not least - the beds are safe, ergonomic and easy to maintain.
To be on the safe side, ask a structural engineer
Designing such a stepped raised bed is not easy, especially if it is a very steep garden with difficult geological conditions. Even planning the stairs, measuring them and then installing them poses problems for the layperson. Retaining walls, for example, must be calculated and built in such a way that they absorb the pressure on the slope. You can safely step down smaller slopes yourself, but for higher slopes with staggered walls and unclear soil conditions, you should always ask a civil engineer or structural engineer.
Which materials are best?
Natural stones or concrete blocks, which can be selected according to size, weight, interlocking and other characteristics, are well suited for building such stepped raised beds. When building, you should also differentiate between walls with laid stones and posed palisade walls. While compacted gravel foundations of around 40 centimeters deep are sufficient for the former, you need a deep trench for palisades. This must accommodate the stone columns up to a third of their length.
Planning stair raised beds
So that you can easily care for the plants in the stepped raised beds, you should calculate the dimensions of the stairs and walls as follows:
- The bed height should be either around 50 centimeters (care while sitting) or 80 to 90 centimeters (care while standing).
- The planted bed depth together with the wall (pay attention to the thickness!) should not be more than 70 centimeters.
- For two or more beds staggered one above the other, a path width of at least 40 centimeters must be added. Otherwise, the next higher bed can be maintained.
- Bed depths of 160 to 200 centimeters are best divided into two planting strips with a middle path and a path in front of the next higher planting terrace.
Tip
On steep slopes, you must also plan the necessary stairs very carefully: For a bed height of 90 centimeters, six steps, each 15 centimeters high, are required.