Once you’re resolved to use gravel as ground cover, the questions stack up. Where to buy it? How to choose it? How much is enough?
Leaving aside glam rock, the best all-around garden choice is usually pea gravel. This term means two things. First, as the name suggests, an individual piece is roughly the size of a pea. Second, when quarry or building supply merchants use it, it is also often the name for a rugged gravel that, at $30 or so a ton, is keenly priced but sharp-edged. So if you have children or pets, look for the more paw-friendly pebble gravel.
In this pebble category, where prices run about $80 to $90 a ton, one type called Del Rio is to gravel what Levi’s are to blue jeans. It’s pretty enough for display, affordable enough for broad use. When dry, its tan and gray stones are highly reflective. This can contribute to glare, but its tones will darken over time.
Mixes are available in yellow to red tones for Southwestern-style gardens and more blue to green for alpine ones. These will often cost far more than Del Rio, but not always. Comparison shopping is essential.
Start with your local building supply merchants and fan out until you have quotes from at least three suppliers. As you do so, watch the units. Measurements used in showrooms can jump from pounds to tons to cubic yards to skips in a single sentence.
The way around this mire of mixed measures is to collect quotes armed with the following information:
1. The size and type of pebble you want.
2. The dimensions of your space.
3. How thickly you want the gravel to be spread.
For size of rock, 3/8 to 1/2 inch is easiest to handle. As for depth, 2 inches is a good standard cover. Go deeper and you will be slipping around in it.
You may be stunned by the price differences. A recent sweep of suppliers produced a range of quotes for a hypothetical order of 3/8 -inch Del Rio to cover a 50-by-50 space. Excluding tax and delivery, the estimates were $1,890 from Southwest Boulder & Stone in Fallbrook, $2,635 from Sunburst Decorative Rock in Irwindale, $1,799.50 from West Los Angeles Building Materials in Inglewood and $1,557 from Bourget Bros. in Santa Monica.
Yet if you move to a more richly toned pea gravel mix, the price tripled at Bourget and skyrocketed by five times at West L.A. Building Supply, while Sunburst and Southwest Boulder and Stone prices varied only a little. Delivery fees ranged from $150 to $310 for the greater L.A. area; a hypothetical trip from the Fallbrook supplier to Van Nuys would have cost $390.
To prepare the garden for gravel, weed the area and then rake back loose top soil. You will want some loose organic matter beneath it, but not much. What is left should be smooth. Part of the beauty of using gravel in native and Mediterranean planting beds is how the seeds will fall into the rock, then root quickly without mulch or dry soil wicking the moisture away from them.
If you order in quantity, the gravel will be dumped in the street or your driveway. To move it, have scoop shovels, at least one wheelbarrow, and some good, hard-tonged bow rakes. Then fill the barrow, make a test dump, rake it out. This will tell you how close together the wheelbarrow dumps should be made. Covering a 50-by-50-foot space should take two able gardeners a morning. It’s hard work, but it’s the last hard work you’ll do on a gravel bed or walk until cursory weeding after winter rains. The upshot will be beautiful, tough and water-savvy.