Potting Bench / Garden Workbench
A drained, beginner-friendly garden workbench for potting and light tasks — timber use class, slatted top, fixings and replaceable wear parts for UK outdoor conditions.
What you'll need
Materials
- Indicative for 1200 × 600mm treated redwood — confirm on site.
- Legs ×4: 75×75mm × 900mm (trim to final height)
- Top long rails ×2: 45×95mm × 1200mm
- Top short rails ×2: 45×95mm × 600mm
- Shelf long rails ×2: 45×70mm × 1120mm (inside legs)
- Shelf short rails ×2: 45×70mm × 560mm
- Top slats ×9–10: 120×25mm × 600mm
- Shelf slats (optional) ×6–8: 90×20mm × 560mm
- Rear lip (optional) ×1: 120×20mm × 1200mm
- Exterior screws; optional oil; feet pads ×4 if on paving
Tools
- Tape measure, square, saw, drill/driver
- optional clamps and sander
Material complexity: Low
Allow one spare slat length on a first build.
Main risk: Moisture held on a flat top or at the leg ground line — rot within a few seasons if drainage and use class are ignored.
Cut list
Legs ×4: 75×75 × 900mm
Top long rails ×2: 45×95 × 1200mm
Top short rails ×2: 45×95 × 600mm
Shelf rails ×4: 45×70 (lengths inside leg layout)
Top slats ×9–10: 120×25 × 600mm
Optional rear lip ×1: 120×20 × 1200mm
Batch-cut slats with a spacer block; pre-drill ends.
Step-by-step
Set height and footprint
Decide finished height from the user's elbow. Mark all legs together. Confirm 1200 × 600mm suits the site and stock lengths.
Tip: One miscut leg wobbles the bench — batch-mark legs before cutting.
Cut frame and ease edges
Cut legs, top rails and shelf rails. Ease arrises on edges your forearms will contact.
Assemble frames square
Build side frames or a full rectangle on a flat surface. Two screws per joint minimum. Check equal diagonals before adding slats.
Tip: Clamp across diagonals while screwing if the frame racks.
Join sides and shelf rails
Connect assemblies with front and back top rails. Add shelf rails at the chosen height. Keep screw lines accessible.
Fit lower shelf
Install slats or ply with gaps if slatted. Do not trap water against the inside face of legs.
Tip: Slatted shelf dries faster than a solid ply panel.
Fit upper slats
Screw slats with 10–15mm gaps using a spacer strip. Optional rear lip after slats are aligned. Screws from below hide heads on the working face but take longer.
Watch out: Do not use a solid sheet top — standing water rots timber quickly.
Place, pad and finish
Set on paving or feet pads — not soil. Let the bench dry in place before oiling visible faces. Brush off compost after use.
Tip: Re-check screws after the first season.
Watch out: Not suitable for heavy workshop machinery or climbing loads.
Tips & traps
- Flat solid top — compost and rain pool; use slats.
- Legs in soil without separation — rot at ground line even if top timber was correct.
- Interior screws — stain and fail; use exterior-grade fixings.
- Over-wide slats without gaps — cupping and trapped water.
- Bench too tall for the user — sore back during repetitive potting.
- Slats nailed or glued beyond repair — screw slats you accept replacing.
Planning & timber detail
Why build this?
A potting bench is one of the most useful small timber projects in a UK garden — and one of the easiest to get wrong by copying indoor bench logic outdoors.
The failure mode is almost always moisture, not joinery complexity. A flat, non-draining top holds compost slurry and rain. Legs buried in soil wick water into the frame. Timber may be “treated” but not for the contact conditions you actually built.
This guide walks through a simple, drained, replaceable bench using stock from a normal UK merchant, with fixings that survive damp cycles and dimensions that suit real potting work.
A potting bench succeeds when you treat it as outdoor furniture that gets dirty, not an indoor bench moved outside. Drain the top, keep legs out of soil, use exterior fixings, and build slats you are willing to replace later.
Where it works best
Works well on a level patio, greenhouse threshold or firm path where legs sit on paving or pads with airflow underneath; sheltered side returns that dry between sessions; kitchen gardens where you want height without going indoors.
Think twice on fully exposed coastal or hilltop sites, shaded north-facing niches where timber rarely dries, or soft lawn without feet or pavers (legs sink; moisture sits at the grass line).
Not for heavy workshop work (vise, planing, machinery) or climbing or sitting loads — light-duty garden station only.
Planning notes
Measure elbow height with shoes on before fixing leg length. Add a centre leg or mid rail on wide (1500–1800mm) variants. Wall-leaning and sink-ready versions need sound fixings and drainage — advanced, not the default. Light-duty only; not structural engineering advice. Verify use-class labels on merchant stock before publish.
Typical sizes
Top overhang 20–40mm past the frame sheds water off leg tops. Lower shelf 150–200mm below top slats. Plan cuts from 2.4m stock; batch-cut slats with a spacer block.
Default dimensions
Default footprint: 1200 × 600mm.
Work height: 850–950mm finished (from user elbow height).
Top: 120×25mm slats with 10–15mm gaps; optional 20–40mm front overhang.
Lower shelf: 150–200mm below top slats.
Design variants
Standard (recommended) — slatted top, lower shelf, four legs, optional rear lip.
Compact (~1000 × 500mm) — small patios; same height logic.
Wide (1500–1800mm) — add centre support to limit rail sag.
Sink-ready — bowl cut-out; maintain drainage; consider a separate guide.
Wall-leaning — fix to solid structure only; not a default.
Mobile — castors compromise stability when pressing down while potting; not recommended as default.
Suitable timber options
Default: treated European redwood frame and slats, 1200 × 600mm footprint, slatted top with 10–15mm gaps, galvanised or stainless exterior screws. Frame: 75×75mm legs (or 90×90mm if stocked), 45×95mm rails, 120×25mm top slats. Optional low rear lip. Optional translucent exterior oil on visible faces after dry-in — not on trapped wet joints.
Larch: credible alternative where local stock is good; same drainage and fixings discipline.
Douglas fir: fine for frame if straight, dry-graded; keep slats narrow.
Western red cedar: excellent for slats if budget allows; softer, dents more easily.
Oak: usually unnecessary — heavy and costly for this role.
Do not use plywood or OSB on the upper surface; ply on the lower shelf only if kept off the ground and accepted as replaceable.
Fixing and finishing
Exterior-grade stainless or hot-dip galvanised screws. Typical: 4.5–5.0 × 50mm for slats; 5.0–6.0 × 75–90mm for frame (adjust to timber thickness). Pre-drill slat ends.
Maintenance
Brush off compost when you finish; do not leave wet soil mats on the top. Expect top slats to be the wear item — plan to replace them in later years. Re-tighten screws after the first season. Refresh oil only if you chose an oil finish and water no longer beads.
Timber behaviour
Durability
Slatted top and airflow under the bench matter more than a thick coating alone. Finish does not replace drainage.
Movement
Gap slats across the width; narrow boards cup less than one wide solid top. Pre-drill slat ends — thin stock splits easily.
Go deeper
Get the Timber Buying Companion
An 8-page practical guide to choosing better boards, avoiding waste and spotting common timber problems before you buy.