How big a backyard putting green should be, and how many cups fit

01How long does the green need to be for the putts I want to practice?

Length matters more than area. Mark Broadie’s analysis of PGA TOUR ShotLink data sorts putts into three bands, short (0 to 6 feet), medium (7 to 21 feet) and long (22 feet and over), and it shows where everyday golfers lose strokes (Broadie, Columbia Business School):

• Tour players one-putt half the time from 8 feet. Golfers who average a score of 90 do it from 5 feet.
• Those 90-shooters average two putts from 19 feet. Tour players get out to 33 feet before they average two.
• The 90-shooters three-putt about 2.3 times a round, four times as often as tour players.

For scale, Southwest Greens, a putting green builder, says most backyard greens are 300 to 800 square feet and its residential greens are usually around 500, against about 1,500 for its commercial greens (Southwest Greens). Within that range the shape follows the goal: long and narrow for lag putts, rounder for short ones.

02How many cups does a backyard green need, and how far apart?

There is no cups-per-square-foot rule. Synthetic Grass Warehouse, a turf distributor, says a green can have as many holes as the space allows, that extremely small spaces may be limited to one, and that cup covers let you rotate which targets are active (SGW). What limits the count is the flat ground each cup needs:

• A flat 3-foot radius around every cup. SGW’s installer columnist says the 3-foot radius around a cup must be flat, smooth and true, checked with a level before the cup goes in (Ask JW: Installing Putting Green Cups).
• 3 feet clear of the fringe. The same columnist says to keep every cup at least 3 feet from the outside fringe (SGW).

So each cup takes a flat circle about 6 feet across, set in from the edge. Two cups at opposite ends of the longest line give medium or lag putts in both directions. A third in the flat zone covers short putts. Past that, extra cups mostly add more places to keep level.

That matters here, because every cup is a fixed point in ground that moves. NOAA’s Fort Collins station averages 150 nights a year at or below 32°F, and its Longmont station, the nearest to Firestone and Frederick, 177.7 (1991–2020 normals). The Colorado Geological Survey says the state’s expansive clays can swell up to 20% by volume when wet (CGS). SGW’s columnist warns that deep freezing can heave the compacted soil around a cup into a “volcano.” He recommends concrete around cups, performance concrete where frost heave is high, and says cups set in concrete outlasted cups set in dirt at installations he revisited over two decades (Ask JW: Are Your Cups Sinking?). Fewer cups, set well, leave less to go wrong over a winter.

03Should part of the green be flat?

Yes. A flat stretch gives you straight, level putts for working on the stroke itself, and it is the easiest place to fit the flat circles your cups need. It also lets you measure speed: the USGA’s Stimpmeter method needs a level area 10 to 12 feet long, ideally 12, or as short as 6 feet with the half-length notch (USGA Stimpmeter booklet). Our guide to putting green speed covers the test itself.

Break belongs around the flat zone, not through the circles at the cups. How break is shaped into the base is on our backyard putting greens page, and how much slope a green can carry is in our guide to a putting green on a sloped yard.

04How much fringe goes around the green?

Enough to stop balls rolling away, and often more. SGW’s columnist says fringe can be several feet wide or as narrow as six inches, that you need it “unless you want the ball to roll off of the green,” and that a green with a good amount of infilled fringe keeps its shape longer (Ask JW on fringe).

• Roll widths set easy sizes. He says most fringe rolls are 15 feet wide, and a roll cut down the middle gives about 7 feet 6 inches a side, in long runs with few seams. SGW’s Putting Green PP 40 surface also comes in rolls 15 feet wide (spec sheet), so a green up to that width can be laid without a seam across the putting surface.
• The fringe is part of the footprint. A green plus a fringe wide enough to chip from takes noticeably more yard than the green alone, and town limits count the whole footprint.

Chipping onto the green, and where a spot to chip from goes, is in our guide to chipping onto an artificial putting green.

05What limits the size of a putting green in Northern Colorado?

Mostly the town code and the lot lines. In Firestone, three rules shape a green (Firestone Development Code 16.6.4):

• A permit first. Firestone requires a town permit before artificial turf goes in, with no fee for single-family homes.
• Coverage. Turf may cover up to 75% of the rear or side yard, with at least 25% left as permeable living landscape. But 50% of the combined side and rear yards must be live plants, and turf can’t count toward that, so in practice turf is held to about half.
• A buffer. At least 3 feet of permeable, living landscape has to separate turf from any property line, so a green and its fringe can’t run to the fence.

The code doesn’t mention putting greens, so plan as though the green and its fringe both count toward those limits. It depends how the town applies them to a green; ask Firestone Planning before you settle the size. Firestone’s turf material rules, such as its minimum pile height, raise their own questions for a putting surface.

In Johnstown, on single-family lots platted since January 1, 2024, the land use code limits “turf and spray-irrigated areas” to 50% of the rear yard, up to 2,000 square feet (Johnstown code, Sec. 17-8-4). It doesn’t say whether artificial turf counts, so it depends; ask Johnstown Planning. Other towns are in our guide to artificial turf rules in Northern Colorado.

Not legal advice: Colorado law bars an HOA from prohibiting artificial turf in the backyard of a detached single-family home, though it can still apply design rules, so the size and placement of a green may still go through review (C.R.S. 38-33.3-106.5, from SB23-178). Our guide to HOA approval for artificial turf lists what a packet needs.

06What should I ask an installer about size and cups?

• What is the longest putt this layout gives me? A good answer names the line, usually corner to corner, in feet.
• Where is the flat zone, and how will you check the ground around each cup? Listen for a level on the base before any cup goes in.
• How will the cups be set, and what happens if one heaves or sinks after a winter? A good answer names what goes around the cup and how a cup gets brought back to height.
• How wide is the fringe, and will there be a seam in the putting surface? Long fringe runs and a putting surface from one roll width are what to look for.
• In Firestone or Johnstown: does this layout fit the town’s limits and the 3-foot buffer, and who files the permit?