At Affinity Water, we’re all about helping you keep life flowing, one simple, seasonal action at a time. Building a rain garden this autumn is an easy way to save water, protect wildlife, and make your outdoor space thrive.
This guide will walk you through what a rain garden is, why it matters, and how to create one step by step.
What is a rain garden?
A rain garden is a shallow, planted area designed to collect and absorb rainwater from roofs, patios, driveways, and other hard surfaces. Instead of water rushing into the drain, it’s naturally filtered through soil and plants.
Think of it as a natural sponge for your garden; slowing, cleaning, and soaking up excess rainwater.
Why build a rain garden?
Creating a rain garden offers benefits for your home and the environment:
- Reduces flooding risk – Captures heavy rainfall and prevents drains from overflowing.
- Saves water – Recharges groundwater naturally and reduces pressure on mains supplies.
- Supports wildlife – Provides food and shelter for pollinators, birds, and amphibians.
- Boosts garden health – Improves soil structure, reduces erosion, and adds seasonal colour.
- Eco-friendly landscaping – A simple way to make your outdoor space more sustainable.
How to build a rain garden this autumn/winter
1. Choose the right location
- Pick a low spot in your garden, at least 3 metres away from your house to avoid damp foundations.
- Look for an area where rainwater naturally flows or where downpipes can be diverted.
- Avoid sites with poor drainage (standing water for more than 48 hours).
Tip: Pour a bucket of water 5–10 litres (a standard household bucket) to mimic a small rainfall. If it drains within 24–48 hours, it’s perfect for a rain garden.
2. Prepare the soil
- Dig a shallow basin (about 15–30 cm deep).
- Loosen compacted soil to help water soak in.
- Mix in sand and compost to create a free-draining soil blend.
This ensures water infiltrates the ground rather than sitting on the surface.
3. Plant the right species
Choose plants that tolerate both wet and dry conditions. For autumn and winter planting, consider:
- Grasses: Carex, Festuca, Deschampsia
- Perennials: Iris, Rudbeckia, Astilbe
- Shrubs: Cornus (dogwood), Sambucus (elder), Viburnum
- Wildflowers: Foxgloves, primroses, and asters for pollinators
Plant in layers: taller plants in the centre, shorter species around the edges. This mimics natural habitats and boosts biodiversity.
4. Add mulch and finishing touches
- Spread organic mulch (like bark or leaf mould) to keep moisture and suppress weeds.
- Edge the rain garden with stones or logs for a natural look.
- Direct downpipes or create a shallow channel to guide rainwater into the garden.
5. Maintain your rain garden
Rain gardens are low-maintenance, but they do need some care:
- Remove weeds in the first year.
- Water young plants in dry spells until established.
- Refresh mulch annually.
- Prune and tidy in late winter or early spring.
Over time, your rain garden will become self-sustaining and wildlife-friendly.
Why autumn/winter is the perfect time to start
- Cooler, wetter weather helps plants establish roots.
- Soil is easier to work after summer heat.
- You’ll be ready for spring showers with a functional rain garden in place.
Creating a rain garden is a simple and rewarding way to make your garden eco-friendly. By capturing rainwater, you can help reduce flooding, conserve water, and attract wildlife, all while beautifying your yard.
Grab your spade and some plants and let this autumn or winter mark the start of your sustainable gardening journey.
If you want to enhance your gardening while saving water, sign up for My Water Footprint. You’ll receive helpful water conservation tips and FREE water-saving devices for your home and garden.
Don’t miss your chance to make a positive impact on your water usage.