Installing a timber picket fence around a raised garden bed is a satisfying weekend project that adds structure, charm, and a little critter protection to your garden. Because this type of fence is low (typically under 1 metre tall) and purely decorative or functional within your own property, it generally doesn't require a building consent — but it's always worth confirming with your local council before you start, as rules can vary.
Plan Your Fence Layout
Before buying any timber, measure the perimeter of your raised garden bed carefully. Sketch a simple plan showing:
- Post positions — space posts no more than 1.8 m apart for a sturdy result, and always place a post at each corner.
- Gate location — if you want access, plan a simple gate opening (600–900 mm wide is typical).
- Picket spacing — a gap of 50–75 mm between pickets looks tidy and lets air circulate around your plants.
Once you have your measurements, calculate how many posts, rails, and pickets you'll need, adding around 10% extra for waste and mistakes.
Choose the Right Timber
For a garden setting, timber durability matters — it will be close to soil and moisture. Good options available from NZ suppliers include:
- Treated pine (H3.2 or H4 rated) — suitable for ground contact and outdoor use. H3.2 is fine for posts that won't be in the ground; use H4 for any post that goes into soil.
- Macrocarpa — a naturally durable NZ timber that looks beautiful and doesn't require chemical treatment.
- Cedar — naturally rot-resistant and lightweight, though it can be pricier.
Avoid untreated pine in a garden environment — it will rot quickly. Check the timber's hazard class rating on the label before purchasing. You'll find a good range of treated timber at Bunnings, Mitre 10, and PlaceMakers.
Gather Your Tools and Materials
| Item | Typical Size / Spec |
|---|---|
| Fence posts | 75×75 mm or 100×100 mm, H4 treated |
| Rails (horizontal) | 75×50 mm, H3.2 treated |
| Pickets | 75×19 mm or 100×19 mm, H3.2 treated |
| Concrete (rapid-set) | One 20 kg bag per post |
| Galvanised nails or screws | 65–75 mm, hot-dipped galvanised |
| String line and stakes | For alignment |
| Post-hole digger or spade | — |
| Spirit level | — |
| Tape measure and pencil | — |
| Saw | Hand saw or circular saw |
Always use hot-dipped galvanised or stainless steel fixings — regular steel will rust quickly outdoors and stain your timber.
Set Your Posts
This is the most important step — a fence is only as good as its posts.
- Mark post positions with stakes and a string line to keep everything aligned.
- Dig post holes to a depth of around one-third of the post length (for a 1 m above-ground post, dig at least 300–400 mm deep). A post-hole digger makes this much easier.
- Place the post in the hole and check it's plumb (vertical) with a spirit level on two adjacent faces.
- Pour rapid-set concrete around the post, following the bag instructions. Brace the post with temporary timber props while the concrete sets — usually 30–60 minutes for rapid-set mixes.
- Allow the concrete to cure fully (at least 24 hours) before attaching rails.
Tip for Raised Beds
If your raised garden bed has a solid timber frame, you may be able to bolt posts directly to the outside of the frame instead of setting them in the ground. Use 10 mm galvanised coach bolts and check the frame is solid enough to take the load.
Attach the Rails
Once posts are set and cured, attach your horizontal rails between posts. For a fence under 1 m tall, two rails (one near the top and one near the bottom) are usually sufficient.
- Cut rails to length and nail or screw them to the inside face of the posts.
- Keep the top rail about 50–75 mm below the top of the posts so pickets can overhang neatly.
- Check rails are level as you go.
Fix the Pickets
- Mark a consistent height line along the rails using a string line or chalk line — this ensures all picket tops are even.
- Space pickets evenly using a timber offcut as a spacer between each one.
- Nail or screw each picket to both rails using two fixings per rail connection. Pre-drilling helps prevent splitting, especially near picket ends.
- Check every few pickets that they're still plumb — small errors can compound quickly.
Picket Top Profiles
You can buy pre-cut pointed or dog-eared pickets, or cut your own profiles with a jigsaw. Pointed tops help shed rain and look classic.
Finishing and Protecting the Timber
Once built, apply a quality exterior timber stain, paint, or preservative to protect the fence and extend its life. Resene, Dulux, and Wattyl all offer exterior timber coatings suitable for garden use. If you're painting near edible plants, check the product is safe once dry — most modern water-based paints are fine when fully cured, but check the manufacturer's data sheet to be sure.
Reapply a protective coat every 2–3 years, or as the manufacturer recommends, to keep the timber looking great.
When to Call a Professional
This project is well within most DIYers' abilities, but consider hiring a qualified fencer if:
- Your site has difficult ground (rock, tree roots, or very wet soil) that makes post setting tricky.
- You want a longer fence run where alignment and post setting accuracy is critical.
- You'd like a gate with latches and hinges fitted correctly.
- You're unsure about any aspect of the build.
A professional fencer will get the job done efficiently and to a high standard. You can find experienced local fencers on tradedirectory.co.nz.
Safety note: Always wear safety glasses and gloves when cutting timber and driving fixings. If you're using power tools, follow all manufacturer safety instructions.
