Leveling Garden Beds With a Laser Level: Flat Even Beds
Leveling garden beds with a laser level comes down to one number. That number is slope, the change in height over a set distance. A laser line or a string with a line level shows that change.
The short answer
Iowa State University Extension notes slope is rise over run. A 1 foot rise over 12 feet is 8.33 percent. Slopes under 5 percent need few special steps. The UW Arboretum notes a flat bed lets water spread out instead of puddling. Cut soil from the high side plus fill the low side.
How do you measure slope for a bed?
The UW Arboretum uses rise divided by run times 100. Run a level line from a stake at the high end. Measure down to the ground at the low end. The drop is the rise.
| Slope | Ratio | What it means |
|---|---|---|
| Under 5 percent | Under 1:20 | Few special steps |
| 8 to 16 percent | 1:12 to 1:6 | Moderately steep |
| 20 percent | 1:5 | Steep |
| About 30 percent | 1:3 | Very steep |
Source: Iowa State University Extension.
How do you level a bed on a slope?
The UW Arboretum advises cutting soil from the upper side plus filling the lower side for a flat bottom. Iowa State notes terraces with walls, stones or timbers create flat planting zones.
How big should raised beds on a slope be?
University of Maine Extension advises terraced beds that run with the contour. Beds 8 to 12 inches tall plus under 4 feet wide work well. Mulch the paths between.
How to: step by step
- Set a stake at each end of the bed.
- Mark a level line between stakes.
- Measure the drop at the low stake.
- Divide rise by run plus multiply by 100.
- Move soil from the high side to the low side.
- Recheck the line before planting.
Troubleshooting
Pooling at one end: uneven bed. Recheck the level line.
Soil washes downhill: steep slope. Iowa State advises terraces.
Bed settles after rain: loose fill. Firm the soil plus recheck.
For bed planning see garden microclimates plus planning an outdoor garden layout. Read raised beds. Kind Seed Co also stocks cannabis seeds.
Sources
- Measuring slope (RGS 2-5), University of Wisconsin Arboretum
- Gardening on slopes and hillsides, Iowa State University Extension and Outreach
- Do you have any tips to help with gardening on slopes?, University of Maine Cooperative Extension
- Controlling soil erosion improves vegetable gardens, University of Georgia Extension
FAQ
What slope counts as gentle?
Iowa State Extension notes slopes under 5 percent generally have few special planting needs.
How do I work out percent slope?
The UW Arboretum divides rise by run plus multiplies by 100.
Why should a bed be level?
The UW Arboretum notes a level bed lets water spread out instead of puddling.
How wide should a terraced bed be?
University of Maine Extension advises no more than 4 feet wide so you can reach the center from either side.
What holds soil in a terrace?
Iowa State notes retaining walls, boulders, field stones, bricks or wooden timbers.
