Slate Chips for Landscaping: Sizes, Depth and Coverage
Slate chips are flat, crushed pieces of slate sold for landscaping. Because the pieces are thin and angular, they lie flat and interlock, which keeps them in place better than round gravel. They come in blue-gray, charcoal, green and plum shades, and many look richer when wet.
Gravel calculator →Common sizes
| Size | Good for |
|---|---|
| --- | --- |
| About 20 mm (3/4 in) | Paths, small beds, between pavers |
| About 30 to 40 mm (1 1/4 to 1 1/2 in) | Beds, borders, general decorative areas |
| 40 mm and up | Slopes, larger features, dry creek beds |
Names and size ranges vary by supplier, so look at a sample before ordering.
Where slate chips work well
- Beds and borders: a tidy, natural look that holds its color.
- Slopes: flat pieces lock together and resist sliding.
- Around ponds and water features: the wet look is a plus.
- Paths: firm underfoot once settled, especially in the smaller sizes.
- Around shrubs: a non-rotting mulch.
Drawbacks
- Edges can be sharp, so they are not ideal for play areas or bare feet.
- Some pets dislike walking on them.
- Leaves and debris are harder to rake out than from smooth stone.
- They cost more than common gravel in many regions.
Installing slate chips
- Mark the area and dig out 3 to 4 inches for paths or 2 to 3 inches for beds.
- Level and firm the soil. For paths, add and compact a crushed stone base.
- Lay landscape fabric under gravel to limit weeds.
- Install edging so chips stay out of the lawn.
- Spread the chips about 2 inches deep for beds or 2 to 3 inches for paths.
- Rake level and walk or tamp lightly to settle.
How much to order
Volume = length × width × depth. Then convert to tons using the supplier's weight. Flat chips leave gaps when loose, so bulk weight is often a little under that of crushed stone. Example with made-up numbers: a bed 8 by 15 feet at 2 inches deep is 8 × 15 × (2 ÷ 12) = 20 cubic feet, or about 0.74 cubic yard. At an assumed 1.2 tons per cubic yard, that is about 0.9 ton. Bulk bags often hold around 0.75 to 1 ton; confirm with your supplier. The gravel calculator runs the math.
Slate chips vs other decorative stone
- Marble chips are bright white and can raise soil pH.
- Pea gravel is smooth and rolls underfoot.
- Decomposed granite packs into a firm, sandy surface.
- Mexican beach pebbles are smooth, dark and high-end.
Upkeep
Rake occasionally to level, blow leaves off in fall and top up thin spots every few years.
Questions people ask
What are slate chips used for?
Garden beds, decorative borders, paths, slopes, around ponds and as mulch around shrubs. The flat pieces interlock and stay put better than round stone.
What size slate chips should I use?
Smaller chips around 20 to 40 mm suit paths and beds; larger 40 mm and up pieces suit borders, slopes and feature areas.
How deep should slate chips be?
About 2 inches for beds and decorative areas is common. Paths often use 2 to 3 inches over a compacted base.
Are slate chips good for paths?
They work on paths, especially on slopes, because the flat pieces lock together. Edges can be sharp, so they are less comfortable for bare feet and some pets.
Do slate chips need landscape fabric?
Fabric under the chips helps keep weeds down and stops the chips from sinking into soil.
What colors do slate chips come in?
Common colors are blue-gray, charcoal, green and plum or purple. Many darken and show more color when wet.
Related guides
- Marble chips
- Landscape fabric under gravel
- Pea gravel patio
- Decomposed granite coverage
- Mexican beach pebbles
As an Amazon Associate, AsphaltTons.com earns from qualifying purchases. Product links below are sponsored.