Landscape fabric, or weed barrier, lets water and air through while blocking the light that weed seeds need to sprout. It is laid under mulch, gravel, pavers or decorative stone. This calculator gives the number of strips, the rolls and the staples for a rectangular bed or path.
How the calculation works
- Effective width of each strip = roll width − overlap
- Strips = 1 + (bed width − roll width) ÷ effective width, rounded up
- Length of each strip = bed length + 6 in to tuck the ends
- Rolls = total length ÷ roll length, rounded up
- Staples = area × staples per 100 sq ft
Example
A 20 × 10 ft bed covered with fabric 3 ft wide, overlapped 6 in, needs 4 strips of 20.5 ft, so 82 ft of fabric: 2 rolls of 3 × 50 ft. At one staple every 3 sq ft (about 33 per 100 sq ft), plan about 66 staples.
Choosing the fabric
| Fabric | Use |
|---|---|
| Woven polypropylene | gravel paths and under stone; strong but harder to cut planting holes in |
| Non-woven (spun-bonded) | under pavers, gravel and rock, and for drainage around French drains |
| Perforated plastic | cheap but short-lived and blocks water poorly |
Heavier fabrics (3 to 5 oz per sq yd) last longer under stone and foot traffic.
Laying the fabric
- Remove weeds and roots, rake the soil level and remove sharp stones.
- Roll out the fabric with the fuzzy side down, if it has one.
- Overlap strips by 6 to 12 in, with the upper strip on top on a slope, so weeds cannot slip through the seams.
- Pin the edges and seams with staples every 12 in, and the middle of each strip every 3 to 4 ft.
- Cut an X where each plant goes, fold the flaps back and tuck them in after planting.
- Cover with 2 to 3 in of mulch or stone to protect the fabric from the sun.
Fabric or not?
Fabric works best under stone and gravel. Under bark mulch in planting beds, the mulch breaks down into soil on top of the fabric, where new weeds then grow, and the fabric can block the organic matter that feeds the soil. Many gardeners prefer a thick layer of mulch over cardboard in beds and keep fabric for paths and stone areas.