Before any materials go into the ground, you need tools to shape the rain garden basin.
Tools required:
- Round-point shovel (for digging)
- Flat shovel (for shaping edges)
- Garden rake (for leveling soil)
- Wheelbarrow (for moving soil and materials)
- Tape measure and stakes (for marking the area)
These tools help you excavate the shallow basin that will hold and absorb rainwater.
2. Marking Materials for Layout
To plan the shape and size of your rain garden, you’ll need simple marking items:
- Wooden stakes
- String or rope
- Spray marking paint (optional)
These help you outline the basin before digging so you maintain proper dimensions and depth.
3. Soil Mix (The Most Important Material)
The soil mix is the heart of a rain garden. Regular garden soil is usually too compact and drains too slowly. A proper rain garden soil mix allows water to infiltrate quickly.
Ideal Rain Garden Soil Mix:
- 50–60% sand (improves drainage)
- 20–30% topsoil
- 20–30% compost
This blend allows water to pass through while still providing nutrients for plants.
You may need to purchase:
- Washed coarse sand
- Screened topsoil
- Organic compost
Mix these thoroughly before placing them into the basin.
4. Gravel or Crushed Stone (Optional but Helpful)
If your native soil drains poorly (clay soil), adding a gravel layer at the bottom improves infiltration.
Materials:
- ½ to 1 inch washed gravel
- Crushed stone
This layer is usually 2–4 inches deep and helps prevent standing water for long periods.
5. Mulch
Mulch is essential for preventing erosion when rainwater flows into the garden.
Best mulch types:
- Shredded hardwood mulch
- Pine bark mulch
Avoid lightweight mulch like straw or leaves, which can float away.
Mulch should be applied 2–3 inches thick after planting.
6. Edging Materials
Edging keeps the rain garden defined and prevents soil erosion.
Common edging materials:
- Natural stones or river rocks
- Bricks or pavers
- Metal or plastic landscape edging
- Wooden garden borders
Edging also helps guide water into the basin rather than letting it spill over the sides.
7. River Rock or Decorative Stones for Inlet
Where water enters the rain garden (from a downspout or slope), you’ll need materials to slow the flow and prevent soil washout.
Use:
- River rocks
- Large decorative stones
- Gravel splash pad
This area is called the inlet zone and protects the soil from erosion.
8. Plants (Critical Living Material)
Rain garden plants must tolerate both wet and dry periods.
You will need a mix of:
- Deep-rooted native grasses
- Flowering perennials
- Shrubs (optional)
- Sedges and groundcovers
Plants are not just decorative—they improve drainage and absorb water.
Choose plants based on the zones of your rain garden:
- Wet bottom zone plants
- Moist middle zone plants
- Drier edge plants
9. Compost or Organic Matter
Compost improves soil fertility and structure. Even if you mix it into the soil blend, having extra compost helps:
- Improve plant establishment
- Encourage healthy root growth
- Increase water absorption
10. Downspout Extension or Drainage Pipe (If Connected to Roof Runoff)
If you are directing roof water into the rain garden, you may need:
- Flexible downspout extender
- PVC drainage pipe
- Elbows and connectors
These guide water safely from the roof to the garden basin.
11. Landscape Fabric (Use Sparingly)
Landscape fabric is not always recommended throughout the garden because it can restrict plant root growth. However, small pieces can be used:
- Under rock inlet areas
- Along erosion-prone edges
Avoid covering the entire rain garden floor with fabric.
12. Level and Measuring Stick
A carpenter’s level or measuring stick helps ensure:
- The basin is level across
- Proper depth (typically 6–12 inches)
- Even water distribution
13. Water Source for Initial Establishment
While rain gardens rely on rainwater, newly planted gardens need regular watering for the first few weeks. A hose or watering can is essential during establishment.
14. Optional: Berm Soil (From Excavation)
The soil you remove while digging can be reused to create a berm (a small raised edge) on the downhill side. This helps contain water within the garden.
15. Safety Materials
Basic safety items make the work easier:
- Gardening gloves
- Knee pads
- Boots
Quick Materials Checklist
| Category | Materials |
|---|---|
| Tools | Shovel, rake, wheelbarrow, stakes, string |
| Soil | Sand, topsoil, compost |
| Drainage | Gravel or crushed stone |
| Surface | Mulch, river rock |
| Structure | Edging stones, bricks, or borders |
| Plants | Native perennials, grasses, shrubs, sedges |
| Water Routing | Downspout extender or pipe |
| Extras | Landscape fabric (limited use), level, gloves |
Why Each Material Matters
Every material plays a specific role:
- Soil mix allows infiltration
- Gravel prevents waterlogging
- Mulch prevents erosion
- Rocks slow incoming water
- Plants absorb and filter runoff
- Edging maintains structure
Skipping any of these can reduce the effectiveness of the rain garden.
Final Thoughts
Building a rain garden does not require expensive construction materials, but it does require the right combination of soil, drainage, protective surfaces, and plants.
With sand, compost, gravel, mulch, stones, and well-chosen plants, you can create a rain garden that:
- Absorbs stormwater efficiently
- Prevents erosion
- Supports pollinators
- Looks beautiful year-round
- Requires minimal maintenance after establishment
By gathering these materials before you start digging, you ensure the rain garden functions properly from the first rainfall and continues to perform for years to come.