| Scenario | Species | Edge | Grip | Climb risk | Estimated reach | Recommended setback |
|---|---|---|---|---|---|---|
| Seed tray on bench | House mouse | Shelf, 15 cm | Medium | Medium | 7.8 cm | 9.0 cm |
| Raised bed with rough wood | Deer mouse | Planter, 10 cm | High | High | 10.6 cm | 12.2 cm |
| Ground edge, smooth collar | Field mouse | Ground, 0 cm | Low | Low | 7.9 cm | 9.1 cm |
This calculator estimates a mouse's practical reach based on body size, stretch, footing, grip, and climb aids. The output is a planning distance for placing seedlings, bait stations, or guards away from edges and footholds.
| Component | Expression |
|---|---|
| Horizontal reach | Reach = (0.62×Body)×Stretch×Posture×Grip×Edge + TailBonus, then apply ClimbAdj |
| Tail bonus | TailBonus = clamp(0.06×Tail, 0, 1.5) |
| Recommended setback | Setback = Reach × (1 + SafetyMargin/100) |
| Vertical reach | Vertical = (0.78×Body)×Stretch×Posture×Grip |
Coefficients are conservative planning values for garden protection. Increase the safety margin when you have nearby climbing supports.
- Select a species preset, or choose Custom for measured values.
- Pick your units and enter body and tail lengths if known.
- Set posture, surface grip, and climb risk to match the area.
- Enter edge type and edge height if plants sit on benches or raised beds.
- Press Calculate reach. Use the recommended setback to position seedlings, bait, or guards.
Why reach distance matters in beds and benches
Small rodents rarely need to enter a tray to cause losses. If tender stems sit near a rim, a mouse can lean, nibble, and retreat without exposure. Reach planning is especially useful for seed-starting benches, raised beds, and compost-adjacent planters where footing is stable and food cues are strong. Even a few centimeters can separate safe seedlings from repeated edge losses in tight spaces.
Inputs that change reach the most
Body length sets the baseline, typically clamped between 3 and 18 cm for planning. The calculator then applies a stretch factor (about 1.05–1.60) plus stability adjustments for posture, surface grip, and edge type. Rough wood, mesh, and twine increase grip, while smooth plastics reduce it. High climb risk adds another boost because nearby clutter acts like steps and handholds, increasing access routes.
Interpreting setback recommendations
Horizontal reach estimates how far a mouse can access from its footing, while vertical reach helps with collars and tall rims. The recommended setback adds your safety margin, creating a practical planting line inside a bed or shelf. For delicate seedlings, a 10–20% margin is common; for high-value starts or frequent sightings, 25–40% keeps damage probability lower. Use the larger value whenever multiple footholds exist.
Guard gaps, collars, and edge details
Physical barriers work when their openings stay tight, and when edges remain difficult to climb. The gap check highlights whether a slot is likely to be secure, borderline, or risky; smaller than about 0.6 cm is treated as tight. Combine small openings with smooth collars, taller rims, and reduced footholds. When an edge is raised, keep nearby boards and bricks away so the height advantage remains meaningful and consistent.
Using results for monitoring and placement
Use the setback number to position bait stations, snap traps in secure covers, or deterrent collars outside the planting zone, and keep attractants away from the rim. If damage continues, increase safety margin and downgrade the grip setting until conditions match reality. Record reach outputs weekly to compare seasons, clutter changes, and crop rotation impacts. A simple log supports better placement decisions over time.
FAQs
What does “horizontal reach” represent?
It estimates how far a mouse can access from its footing without fully climbing into the protected area. Use it to plan how far plants, bait stations, or guards should sit from an edge or foothold.
Why is there a safety margin setting?
Real gardens include unpredictable footing and clutter. The margin adds buffer to the setback so you plan for worst‑case access. Increase it when you see repeated damage or when trellises and pots create step‑ups.
Should I use Custom measurements?
Use Custom when you have field measurements or when local mice appear larger than typical. If unsure, start with a preset, then adjust body and tail lengths until results align with observed access and damage patterns.
How do edge height and vertical reach work together?
Vertical reach helps judge whether a mouse can get paws over a rim or collar. Taller, smoother edges reduce leverage, but nearby footholds can cancel that benefit. Keep clutter away from raised rims for best effect.
What guard gap value is considered safer?
Tighter is better. As a planning rule, openings around 0.6 cm or smaller are treated as “tight” in the calculator. If you must use larger mesh, add a smooth sleeve or secondary liner to reduce access.
Does climb risk replace real inspection?
No. It is a planning adjustment. Walk the perimeter and remove ladders: stacked pots, boards, trellis ties, hoses, and low branches. Then recalculate using a lower climb risk to confirm your updated layout.