As a general rule, you should wait at least 28 days before doing any significant landscaping around freshly poured concrete. That said, the exact timing depends on what type of landscaping you're planning — light work like placing potted plants can happen sooner, while heavy earthworks or retaining walls need the full cure time or longer.
Why Curing Time Matters
Concrete doesn't simply "dry" — it cures through a chemical process called hydration, where water reacts with cement to form a hard, durable matrix. Disturbing the slab or the ground around it too early can cause cracking, edge damage, or settlement that's expensive to fix. In New Zealand's variable climate — from the humid north to the cold, frosty south — curing conditions can vary significantly and affect how quickly concrete reaches its design strength.
BRANZ notes that concrete typically reaches around 70% of its design strength at 7 days and close to full strength at 28 days under normal conditions.
A Rough Timeline for Different Activities
| Activity | Minimum Wait Time |
|---|---|
| Light foot traffic | 24–48 hours |
| Removing formwork (simple slabs) | 24–48 hours |
| Wheelbarrow or light equipment | 7 days |
| Edging, garden borders, pavers nearby | 7–14 days |
| Planting shrubs or trees close to edge | 14–28 days |
| Heavy earthworks, retaining walls, machinery | 28 days minimum |
| Backfilling against a concrete wall | 28 days minimum |
These are guides only — always check with your concreter, as mix design, slab thickness, and weather all affect cure rates.
Factors That Affect Curing in NZ
Temperature and Weather
Cold temperatures slow curing significantly. In places like Otago, Canterbury, or Central Plateau, winter pours may need extra time or protective measures (like curing blankets) to reach strength. Hot, dry nor'west conditions in places like Marlborough or Canterbury can cause the surface to dry too fast, leading to shrinkage cracks. Your concreter should account for these conditions.
Concrete Mix Design
Higher-strength mixes (e.g. 25 MPa vs 17.5 MPa) may cure at different rates. Blended cements with fly ash or slag can cure more slowly but ultimately achieve excellent strength. Ask your concreter what mix was used so you can plan accordingly.
Slab Thickness
Thicker slabs — such as those for driveways or structural pads — retain moisture longer and may need more time before heavy loads are applied nearby.
What Landscaping Can You Do Early?
After 24–48 hours, you can generally:
- Walk carefully across the slab on foot
- Remove timber formwork from simple slabs (check with your concreter first)
- Place lightweight potted plants away from the edges
After 7 days, you can typically:
- Use a wheelbarrow nearby
- Begin laying pavers or garden edging at least 300–500 mm from the slab edge
- Start light soil preparation in adjacent garden beds
Avoid digging, compacting soil, or operating machinery close to the slab until the 28-day mark.
Protecting the Edges
The edges and corners of a concrete slab are the most vulnerable during the early curing period. Avoid:
- Backfilling soil hard against the edge before 28 days
- Running irrigation water directly onto or under the slab
- Planting trees or large shrubs too close — roots can eventually lift or crack concrete over time
For garden beds directly adjacent to concrete, consider installing a physical root barrier and leaving a small expansion gap to allow for movement.
Does Landscaping Require a Building Consent?
Most residential landscaping around a concrete slab won't require a building consent, but there are exceptions. Retaining walls over 1.5 metres in height typically require consent under the NZ Building Code, and some councils have lower thresholds. Structures like pergolas, decks, or garden sheds attached to or near the concrete may also need consent.
Always check with your local council before starting, and refer to MBIE Building Performance for guidance on Schedule 1 exemptions.
When to Call a Professional
If you're planning significant landscaping — such as retaining walls, drainage changes, or structures near the new concrete — it's worth getting a qualified concreter or landscaper involved early. They can advise on:
- Whether the slab design is suitable for what you're planning
- Correct drainage to prevent water pooling under or around the concrete
- Expansion joints and edge details that protect long-term durability
For any work that involves plumbing or drainage near the slab (e.g. stormwater, irrigation connections), you'll need a licensed drainlayer — check the Plumbers Gasfitters & Drainlayers Board for licensed practitioners.
You can find qualified local concreters and landscapers on tradedirectory.co.nz to get the job done right from the start.
Site Safe
