Weed Mat Nails vs U-Pins: Which Holds Better?
Weed mat only works if it stays flat. Once wind lifts an edge, light gets in and weeds come back. The two most common ways to hold it down are plastic weed mat nails with a cap and galvanized steel U-pins, also called landscape staples. The choice comes down to your soil, your wind and whether you also need to hold drip pipe. Here is how they compare and which one to use where.
The two options at a glance
| Plastic weed mat nails | Galvanized U-pins | |
|---|---|---|
| Material | UV-stabilised polypropylene | Galvanized (zinc-coated) steel |
| Length | 6 inch (about 15 cm) or 7 inch (about 18 cm) | About 6 inch (15 cm), 1.5 inch (3.8 cm) wide |
| Grip | Barbed shank resists pull-out | Two legs in the soil |
| Top | Wide flat cap spreads load on fabric | U bridge straddles fabric or pipe |
| Rust | Cannot rust or stain | Zinc coating resists rust |
| Holds drip pipe | Can pin pipe | Straddles 16 mm pipe without crushing it |
Both come in packs of 100, 200, 500 and 1000.
When to choose plastic weed mat nails
- You want the fabric protected. The wide flat cap spreads pressure, so it does not tear woven mat or thin mulch film.
- You are pinning more than weed mat. The same nails hold mulch film, shade net, frost fleece, drip pipe and tarpaulin to the ground.
- You do not want any rust. Plastic cannot rust or leave stains on the mat.
- Soil is firm (6 inch) or loose and sandy (7 inch). The barbed shank bites into the soil, and the extra inch on the 7 inch nail helps in sandy, loose or windy sites.
Choose 6 inch weed mat nails for firm garden and field soil, and 7 inch weed mat nails for sandy, loose or exposed ground.
When to choose galvanized U-pins
- Drip pipe runs under or beside the mat. The U shape straddles 16 mm pipe without squeezing it, so one pin can hold both pipe and fabric.
- You are pinning joins. The two legs can pin two overlapping layers of fabric at once.
- You want extra hold. Two legs in the soil give a broad grip along edges and overlaps.
- You want to reuse them. Pull them out and use them again next season.
See our 16 mm galvanized U-pins (landscape staples).
Verdict: which holds better?
Neither wins everywhere. In practice, many growers use both:
| Situation | Best choice |
|---|---|
| Edges of mat in firm soil | 6 inch nails |
| Edges in sandy, loose or windy sites | 7 inch nails |
| Overlaps and joins | U-pins (holds two layers) |
| Where drip pipe crosses or runs alongside | U-pins |
| Mulch film, frost fleece, light covers | Nails (wide cap protects thin film) |
| Shade net or tarpaulin pinned to the ground | Nails |
How many do you need?
Our product guidance is one pin every 1 to 1.5 m along the edges and every 30 to 50 cm along joins and overlaps. For a 100 m roll pinned on both edges every 1 m, plan on about 200 pins, plus extra for joins.
| Area | Edge pins at 1 m | Pack to buy |
|---|---|---|
| Kitchen garden, 30 m of edges | 30 + joins | 100 |
| One 100 m roll, both edges | 200 | 200 |
| Five 100 m rolls | 1,000 | 1000 |
How to fit them properly
- Lay and stretch the mat flat before pinning.
- Pin the four corners first, then the middle of each edge.
- Fill in every 1 to 1.5 m along edges and every 30 to 50 cm along joins.
- Push nails straight in until the cap sits flush. In hard ground, tap gently with a mallet.
- Fit U-pins over the drip pipe or overlap with both legs fully in the soil.
Related guides
Read our step-by-step weed mat laying guide, see how to keep drip lines in place with 16 mm stakes and U-pins, and compare our weed mat rolls.
Shop weed mat nails → Shop U-pins →
Frequently asked questions
Are plastic weed mat nails as strong as metal U-pins?
For holding fabric, yes in most soils. The barbed shank resists pull-out and the wide cap holds a broad area. U-pins give extra hold at joins and over drip pipe.
What is the difference between 6 inch and 7 inch weed mat nails?
Both have the same cap and barbed shank. The 7 inch nail has an extra inch of shank for sandy, loose or windy sites; the 6 inch suits firm soil.
Will U-pins crush my drip pipe?
No. Our U-pins are sized to straddle 16 mm drip pipe without squeezing it.
Do weed mat nails rust?
No. Our nails are UV-stabilised polypropylene, so they cannot rust or stain the mat. U-pins are galvanized to resist rust.
How many weed mat nails do I need?
About one every 1 to 1.5 m along edges and every 30 to 50 cm along joins. A 100 m roll pinned on both edges every 1 m needs about 200.
Can I reuse nails and U-pins?
Yes. Both can be pulled out and reused when you relay or move the mat.
