What to Put Under a Trampoline: Grass, Rubber Mulch, Mats or Nothing at All

The three jobs the ground has to do

One: stay level. A trampoline frame transfers the whole jumping load into a handful of legs. If one leg sits in a hollow or on soft ground, that leg works itself down, the frame racks, and the net and pad stop sitting where the maker intended. CPSC asks for a level site clear of structures, trees and other play areas, and every maker repeats it. Level ground is the only one of the three jobs that is genuinely non-negotiable (trampoline on a slope).

Two: stay clear. The space under the mat has to stay empty. A mat deflects a long way under an adult, and anything stored under there (a hose reel, bikes, bricks holding the legs, the lawnmower) is something a jumper can reach. This is also the argument against gravel and pavers directly under the frame: you are putting a hard surface exactly where a mat deflects to.

Three: soften a fall at the edge. Falls off a trampoline happen at the rim and they land outside the frame, not under it. That is where surfacing earns its keep, and it is why a ring around the trampoline matters more than anything directly beneath the mat.

Every option, and what it actually does

The surfacing claims here come from the makers' own published depth and fall-height tables, cited on the product cards below.

Two of those rows need a word more. A trampoline on a hard surface is a specific install with a specific method, not a shortcut, and it changes how you anchor as well as what you put down (anchor a trampoline on concrete, turf or sand, and a trampoline on a deck if the hard surface is timber). And if the question behind yours is really about the lawn rather than the fall, the honest answer is on do trampolines ruin grass.

If you use rubber mulch, use the depth table

Loose-fill surfacing only works at depth, and the depth is published. GroundSmart's playground mulch table asks for 5 in, compacted to 4 in, to protect a 10 ft fall height, 6 in compacted to 5 in for 12 ft, and 7 in compacted to 6 in for 16 ft; the shredded product needs 7 in for 9 ft. CPSC's own handbook calls for 9 in of loose fill under equipment up to 8 ft. Three inches of mulch scattered for the look of it protects nothing, and that is the most common version of this mistake.

A trampoline's fall height is lower than a playset deck, because a jumper leaves the mat at around 3 ft and the hazard is the frame rail rather than the drop. That makes a 4 to 5 in compacted ring around the frame a sensible target rather than the full 9 in a tower needs. Contain it with an edge, keep it off the mower's path, and top it up every spring, because loose fill compacts into a hollow at the entry within a season (best playground mulch and surfacing).

What to buy for the ground

Three different jobs, three different products. Pick by which of the three jobs above you are actually solving.

Mistakes to avoid

• Levelling with bricks or paving slabs under the legs instead of levelling the ground.
• Storing anything under the mat, including the ladder and the hose.
• Scattering three inches of mulch and calling it protective surfacing.
• Laying loose fill over an unlevelled hollow, which hides the problem instead of fixing it.
• Using carpet offcuts or gym mats as the main surface, which CPSC specifically warns against.
• Putting a trampoline on gravel, pavers or a patio with nothing in between.
• Forgetting that anchoring still has to work through whatever you put down (how to anchor a trampoline).