Planter Box - Arlingtonva
Urban Planter Box - Common Dos and Don’ts Typical Installation Perforated underdrain (minimum slope of 0.5%), covered with 9” VDOT #57 stone, followed by 3” pea gravel, followed by 18”-30” of soil media, followed by 2” shredded hardwood mulch. Proper ponding depth (6”-12”) should be provided above the soil/mulch layer. CHECK PLANS FOR PROPER PONDING DEPTH AND SOIL MEDIA DEPTH!
Acceptable
Perforated underdrain
9” VDOT #57 stone
3” pea gravel
18” – 30” soil media mix
2” mulch
Not Acceptable
GEOTEXTILE FABRIC Geotextile fabric should NOT be used in between any layers in an urban planter box.
10’ – 12” VDOT #57 stone
3” pea gravel
No filter fabric over #57 or pea gravel!
March 2015
Perforated Underdrain
Waterproofing
Overflow Pipe Cap
Underdrain should be perforated schedule 40 PVC with 3/8” holes (4 rows), spaced 6” on center.
A waterproof liner (seal all seams) or waterproofing sealant must be applied to the inside of the planter box.
Acceptable
Acceptable
Acceptable
Recommended
Not Acceptable
Not Acceptable
Not Acceptable
March 2015
Downspout and Overflow Pipes Downspouts should enter planter box away from the overflow pipe, and proper energy dissipaters (splash block/rocks) should be installed at each downspout.
Acceptable – Recommended
Acceptable – Not Ideal Examples of corrections in the field after installed incorrectly.
Not Acceptable Do not install downspouts directly above overflow pipe.
March 2015
Acceptable
Perforated underdrain
9” VDOT #57 stone
3” pea gravel
18” – 30” soil media mix
2” mulch
Not Acceptable
GEOTEXTILE FABRIC Geotextile fabric should NOT be used in between any layers in an urban planter box.
10’ – 12” VDOT #57 stone
3” pea gravel
No filter fabric over #57 or pea gravel!
March 2015
Perforated Underdrain
Waterproofing
Overflow Pipe Cap
Underdrain should be perforated schedule 40 PVC with 3/8” holes (4 rows), spaced 6” on center.
A waterproof liner (seal all seams) or waterproofing sealant must be applied to the inside of the planter box.
Acceptable
Acceptable
Acceptable
Recommended
Not Acceptable
Not Acceptable
Not Acceptable
March 2015
Downspout and Overflow Pipes Downspouts should enter planter box away from the overflow pipe, and proper energy dissipaters (splash block/rocks) should be installed at each downspout.
Acceptable – Recommended
Acceptable – Not Ideal Examples of corrections in the field after installed incorrectly.
Not Acceptable Do not install downspouts directly above overflow pipe.
March 2015
