How do I calculate how many planter boxes I need to line a 100-foot walkway?

Alright, let me walk you through this like I’m standing right there with you, tape measure in hand. I’ve done this before—trying to line a long walkway with planter boxes is both exciting and a little tricky if you don’t nail the math. So, here’s how I figure out exactly how many you’ll need for a 100-foot stretch.

First, decide on the length of each planter box. I usually recommend between 2 and 4 feet long for a walkway, because anything smaller looks like clutter and anything larger starts to feel overwhelming. Let’s say you choose 3-foot-long boxes. Now, you also need to account for spacing between each box. I personally like to leave about 2 feet of open space between planters—this creates a rhythmic, breathable look and allows for easy foot traffic or maintenance access.

So, for each “unit” (one planter plus the gap after it), you have 3 feet + 2 feet = 5 feet. Now take your total walkway length: 100 feet. Divide that by 5, and you get 20. That means you can fit 20 planter boxes along the walkway if you place them end-to-end with a 2-foot gap after each. But here’s the thing—do you also want a gap at the very beginning or end? Sometimes I start with a planter right at the entrance and end with one at the far side. In that case, you’ll need 21 planters, because the last one won’t have a gap after it.

If you prefer a different spacing—say, 1.5 feet between each—your unit becomes 4.5 feet, and you’d need about 22 planters (100 divided by 4.5). See? The math bends to your style.

Also, consider the plants you’ll use. Taller, bushier plants might need more breathing room, so you’d space the boxes wider. Low groundcovers or succulents? You can pack them tighter. I always tell people: measure your walkway length, pick your box length, decide on a gap that feels right to your eye, then do that simple division. And don’t forget to add one more box if you want both ends to have a planter.

So for a 100-foot walkway, with 3-foot boxes and 2-foot gaps, you’re looking at about 20 to 21 planter boxes—depending on whether you start and stop with a gap. But honestly, the best number is the one that makes your walkway feel welcoming and balanced. Trust your eye after you do the math, and you’ll nail it.