My attempt at a backyard rain garden flooded my patio last spring, here's what I figured out

I built a small rain garden in my side yard in Portland last April to catch runoff from the roof. Thought I followed all the YouTube guides, dug it about 6 inches deep, filled it with gravel and native plants. First big storm came and water just sat there for three days, then overflowed right onto my neighbor's walkway. Turns out I didn't check how compacted my clay soil was under the gravel, so nothing drained. I had to rip it all out, dig down 2 feet, and mix in sand and compost before replanting. Cost me an extra $90 in materials and a whole Saturday. Anyone else hit a snag like this with their first drainage project?

3 comments

3 Comments

miam7510d ago

That clay soil is tricky. I had the same issue with my first rain garden here in Portland, had to dig a percolation test hole first to see how fast the water actually soaked in. A good two feet of amended soil really does make the difference, I learned that the hard way too.

brown.gavin10d ago

Heard a local landscaper say you gotta mix in compost with the topsoil too.

rubyk868d ago

And yeah, you're spot on about the percolation test. I had a friend up in Seattle who tried building one without checking first, and three days after a heavy rain her yard was still a swamp. She said the water was just sitting there, not moving at all. I told her what @miam75 said about digging a test hole, and she finally gave it a shot. Surprise surprise, the clay was way worse than she thought. Now she's got the amended beds like you described and things actually drain. Funny how one simple test saves so much trouble.