How to Dig a Trench with a Trench Spade Fiberglass
By Radius Garden | Published: 2026-10-27
Category: How-to Guides
Learn the correct technique for digging narrow, precise trenches with a fiberglass trench spade—from marking the line to clearing soil—plus common mistakes to avoid.
Quick Answer
To dig a trench with a trench spade fiberglass, mark your line, cut the edges with the spade's narrow blade, lift soil in thin slices, and clear the trench as you go—keeping the blade perpendicular to the ground for straight walls.
Why a Trench Spade Beats a Regular Shovel
A standard shovel has a wide, curved blade that makes it hard to cut clean, straight sides. A trench spade's narrow, flat blade is designed to slice through soil with less disturbance, which is essential for irrigation lines, edging, or planting bulbs.
The fiberglass handle on the Radius Garden Trench Spade Fiberglass keeps the tool lightweight, reducing fatigue during repetitive digging. This matters because trenching involves many small cuts rather than one big scoop, so a lighter tool lets you work longer without strain.
When a Trench Spade Isn't the Best Choice
For shallow, wide planting holes or moving large amounts of loose soil, a round-point shovel or a spade with a broader blade will be faster. The trench spade's narrow blade is a precision tool—it excels at straight, narrow cuts but not at bulk excavation.
If you're digging in extremely rocky or compacted ground, you may need a pick or a mattock to break the soil first. A trench spade can handle firm soil, but it isn't designed to smash through large rocks or roots.
Step-by-Step Trench Digging Process
- Mark the Trench Line: Use string and stakes or a line of flour to outline the exact path and width of your trench. This gives you a visual guide and prevents wandering cuts. Check that the width matches your pipe or cable before you start digging.
- Cut the Edges First: Position the blade perpendicular to the ground and press it straight down along the marked line to cut the sides. This creates clean, vertical walls and makes the next steps easier. Keep the blade vertical—leaning it will make the walls sloped and unstable.
- Lift Thin Slices of Soil: Insert the spade at a slight angle and lift a thin slice of soil (about 2–3 inches deep) rather than trying to scoop a large chunk. This reduces strain and keeps the trench uniform. If the blade won't penetrate, water the soil a few hours beforehand to soften it.
- Clear the Trench as You Go: After every few cuts, use the spade to scoop out the loosened soil and deposit it on a tarp or wheelbarrow. Keeping the trench clear lets you see the bottom and maintain depth. Don't let soil pile up at the edges—it can fall back in and hide uneven spots.
- Check Depth and Straightness: Periodically place a straight board across the trench and measure depth with a tape measure. Also sight down the line to ensure the walls are straight and the bottom is level. Fix any low spots now; it's much harder to correct after you lay pipe or cable.
Tool to Use
- Trench Spade Fiberglass: The Radius Garden Trench Spade Fiberglass has a fiberglass build that provides durability and resistance to corrosion, and its optimized shape is designed for clean, narrow trenching in tight spaces. This means you get a lightweight, rust-resistant tool that cuts precise trenches without the extra weight of a steel-handled shovel, reducing fatigue during repetitive digging.
Trench Spade Fiberglass
