How to read a pebble grading and match stone size to the job — joints, beds, paths, drainage and water features — plus the size-related terms to confirm in writing before ordering bulk landscaping pebbles from China.
Two pebble quotations can share the same colour family and the same polished finish and still be for two different products, because the grading — the size range the stones fall into — decides how the finished surface looks and behaves. This guide explains what a pebble grading actually specifies, how to match a grading to each landscape job, and which size-related points to confirm in writing before a bulk order of landscaping pebbles leaves China.
What a Pebble Grading Actually Specifies
Decorative pebbles are traded by particle size, quoted as a range in millimetres rather than a single number. The range is the honest description: natural stone is never one size, and every grading carries a permitted share of stones above and below the nominal band. What a buyer is really purchasing is the distribution between those limits — that is what decides whether a surface settles into a tight, quiet finish or reads as loose, individual stones.
Nominal size is a range, not an exact dimension
Because pebbles are rounded natural stone rather than crushed and milled material, no two batches are identical. Two offers that both read “mid-range” can behave differently if one sits at the lower edge of the band and the other at the upper edge. The practical protection is simple: compare every offer on the stated range in millimetres, and treat a quotation that gives no range as unfinished.
How gradings are verified
Grading is measured by sieve analysis — passing a sample through a stack of test sieves with known apertures and weighing what each fraction retains. The method is standardised for aggregates, and the standard quoted verbatim at the end of this article describes exactly this procedure, so the numbers are reproducible in any laboratory. For export orders the usual verification path is a sample bag by courier, sieve data on request for the production batch, and third-party inspection at loading for high-value projects. Our mesh size guide explains the sieve logic used across the mineral powder lines; the same logic carries over to decorative stone.
Matching the Grading to the Job
The fastest way to choose a size is to start from what the surface has to do, not from the colour card. Our pebble range runs from the smallest decorative gradings at around 3–5 mm up to 60–90 mm statement stone, and each part of that ladder has jobs it simply does better:
- Joints between pavers and stepping stones — the smallest gradings settle tightly, stay put underfoot and read as a neat jointing line.
- Planter tops, beds and borders — mid-range gradings cover soil and weed membrane fully without swallowing small plants, and they stay in place better than fine material when you water or weed.
- Paths and courtyards — mid gradings give a stable walking surface once they have settled into the base.
- Dry river beds and drainage strips — larger stones carry water visually and literally, and the voids between them let storm water pass.
- Rockeries, water features and feature paving — the largest gradings, up to 60–90 mm, read as individual stones and are the ones worth polishing to a high sheen.
Small gradings: joints, pots and tight coverage
Small stone does the quiet work. Between pavers it locks into the joint and resists lifting; in pots it shades the root zone and stops compost washing out in the rain. Because small gradings put many more stones into every square metre, colour consistency between bags matters more than it does for large stone — which is where hand-sorting before polishing earns its place.
Large gradings: water, slopes and statement surfaces
Large round stone is self-draining by geometry: water passes through the voids instead of ponding on the surface. On slopes, larger stones stay where they are put while small gradings creep downhill with the rain. And because a few large stones cover more area per stone, the surface reads calmer and more deliberate — which is why designers reach for the upper end of the range at entrances and around water.
Traffic, Depth and Slope: the Practical Size Checks
Three site conditions refine the choice above. Foot traffic favours gradings whose stones lock together; very large round stones roll underfoot, so save them for areas people admire rather than cross often. Wheelbarrows and occasional vehicles need a deeper, well-settled base under a mid grading — and a decorative pebble surface is not the right running surface for cars, whatever the size. Finally, depth should scale with stone: the larger the stone, the deeper the layer needs to be before the surface stops moving. Ask for coverage guidance per grading when you request a sample, because the right depth depends on the grading and the base, and confirm it with a trial area where the project allows. These are checks a landscape contractor will run anyway; running them before ordering costs nothing.
Confirming Size in Writing Before You Order
- The grading range and its tolerance — state the range in millimetres and ask that production be screened to it, so every offer and every batch is measured the same way.
- Colour per grading — colour is sorted by hand after polishing, so agree the tone against an approved sample rather than a colour name.
- Packing that suits the size — pebbles ship in 20 kg / 25 kg woven bags, then into 1000 kg tonne bags or on pallets, or in bulk in 20 ft containers; retail-ready small bags are available for garden-centre ranges.
- Order size per line — one 20 ft container per colour and size is the usual export minimum, so plan a project's size list around container economics.
- Project-specific gradings — mixed-colour and custom size ranges can be produced to order; sample bags go by courier before booking.
Sourcing Graded Landscaping Pebbles from TDHX
TDHX's landscaping pebble range covers gradings from around 3–5 mm up to 60–90 mm across white, red, green and wood-brown lines, with a natural multi-colour line in between. The stones are screened, tumbled and polished in our own plant in Haicheng, China — see the natural multi-colour landscaping pebbles and wood brown pebbles pages for the two lines buyers most often combine. Colour choice is a design question we cover separately in white pebbles for garden design; laying practice, base preparation and aftercare are step-by-step in how to lay decorative pebbles; and where a project needs a finer covering material, decorative white sand complements the pebble lines. For industry context, see our landscaping and garden applications page — and send your grading list with the areas to be covered, and we will come back with gradings, packing and a sample plan.
