How to Install a Corten Pou Whenua

Your pou whenua is designed to go in without fuss. Most gardens need nothing more than a firm push; exposed spots or hard ground are better with a little concrete. Here's how to choose, and what to expect as your pou weathers.

What's in the box

One corten steel pou whenua with sharpened base prongs. The Iti is 120 cm overall and stands about 1 m above ground; the Nui is 150 cm overall and stands about 1.3 m above ground. That leaves about 20 cm of prong in the ground.

Before you start

1. Choose the spot. Walk around with the pou and look at it from the house, the path and the gate before committing.
2. Check underground. Avoid irrigation lines, cables and pipes. If in doubt, dig a small test hole first.

Option 1: Push it in

Best for garden beds, lawns and soft or loamy soil in sheltered spots.

1. Water the spot well the day before if the ground is dry. Damp soil takes the prongs far more easily.
2. Stand the pou upright on the spot and check it's facing the way you want.
3. Press it down evenly, using your body weight on the shoulders of the pou. For firmer ground, place a block of timber on top and tap gently with a rubber mallet, moving side to side so it goes down straight.
4. Push it in until the prongs are fully buried and the base sits at ground level.
5. Check it's vertical with a spirit level on two faces, then firm the soil around the base with your foot.

Option 2: Set it in concrete ( useful for exposed, windy or hard ground)

Best for clay or stony soil, windy or coastal sites, high-traffic spots, or anywhere tamariki might lean on it.

You'll need: a spade, a bag of rapid-set post concrete, a spirit level, water, and two stakes with string or tape to brace the pou while it sets.

1. Dig a hole about 30 cm deep and 25 cm wide, wide enough to surround the prongs.
2. Add 5 cm of gravel to the bottom for drainage.
3. Stand the pou in the hole with the prongs resting on the gravel and the base at finished ground level.
4. Brace it upright with the stakes and string, and check it's vertical on two faces.
5. Pour in the dry concrete mix and add water as the bag directs. Check vertical once more.
6. Leave the bracing in place for the setting time on the bag, then backfill the top few centimetres with soil, bark or gravel to hide the concrete.

How corten weathers

Corten is a weathering steel. When it meets rain and air it forms a stable, rust-coloured layer that protects the steel underneath, so it doesn't need paint, oil or sealing.

• Week 1–4: the grey mill finish starts to show orange patches.
• Months 1–6: the colour deepens and evens out to orange-brown. 
• After about 6–12 months: a settled, deep russet patina.

Wet-dry cycles build the patina; a pou that stays constantly wet weathers more slowly. To speed it up, mist the pou with water every day or two for the first few weeks.

Care

• Nothing to do, most of the time. Brush off leaves and mud if they collect at the base.
• Keep mulch and soil off the steel. A pou buried in damp mulch or soil above its base stays wet and weathers unevenly.
• Coastal gardens. Salty air keeps corten from fully settling. Your pou will still look beautiful, but within a few hundred metres of the sea the patina may keep developing for longer.

Need help?

If your pou is going somewhere unusual (a raised planter, decking, a rock garden), or you'd like a custom height, email us at kiaora@ahocreative.com and we'll talk it through.

→ See the Pou Whenua