Advanced options
Based on 2.4m softwood sleepers laid flat (200mm face). Use new treated softwood or untreated oak for veg beds, never reclaimed railway sleepers indoors or around food: the old tar-creosote ones are banned from garden-contact use. Stagger joints between layers like brickwork and screw layers together with 200mm+ landscaping screws.
What The Sleeper Calculator Works Out
- Sleepers needed: the bed perimeter (2 x length + 2 x width) divided by the sleeper length, rounded up, then multiplied by the number of layers. The garden sleeper standardised at 2.4m x 200mm x 100mm, so a classic 2.4m x 1.2m bed is three sleepers per layer and six for the two-layer 40cm bed most veg growing wants.
- Fixings: two 200mm+ landscaping screws per sleeper to lash the layers together, plus two per sleeper on the bottom course for corner pegs or ground fixings. Drive them at an angle and stagger joints between layers like brickwork.
- Soil to fill: length x width x finished height, in cubic metres and 0.7m3 bulk bags. A two-layer 2.4m x 1.2m bed swallows over a cubic metre; a lasagne of subsoil, organic matter and topsoil is far cheaper than bagged compost throughout.
- Sleeper length and face height (advanced): switch to 1.2m, 1.8m or 3.0m sleepers, or to the chunkier 250 x 125 section, or lay 200 x 100 on edge for a 100mm step. The soil volume and bed height update to match.
- Cutting-list sleepers (advanced): instead of dividing the perimeter, this cuts two long sides and two short sides per layer (the short sides sit inside the long ones, so they lose two sleeper thicknesses) and packs the pieces into whole sleepers. It is often one fewer than the simple count on beds whose sides fold neatly into a sleeper, and shows the offcut you will have left.
- Sleeper and soil cost (advanced): enter a price per sleeper (new treated softwood is typically GBP 20 to GBP 35 a 2.4m length, oak GBP 45 to GBP 70) and a price per bulk bag of topsoil (GBP 60 to GBP 110 delivered) to see the materials bill.
- Liner needed (advanced): perimeter x bed height plus a 100mm tuck-under, in square metres of heavy polythene. A liner keeps treated timber and the soil apart, which extends softwood and makes the treatment chemistry academic for veg beds.
- Bed height and timber weight (advanced): the finished height in centimetres and a rough weight of the timber at about 11kg per metre of 200 x 100 softwood, useful for planning delivery and lifting. A 2.4m sleeper is a two-person carry.
- Number of identical beds (advanced): multiplies every quantity, so a four-bed kitchen garden can be priced in one go.
- Layer table (advanced): sleepers, soil and cost for one to four layers so you can see what the extra no-bend tier really costs. Reclaimed tar-creosote railway sleepers are prohibited where skin or food contact is likely, which rules them out for veg beds.