That’s funny, because I’ve definitely fallen for the “fancier is better” trap a few times. Last spring I tried this multi-layered setup with gravel, charcoal, coconut coir, and some pricey liner that was supposed to be “self-watering.” It looked great for about a week, then the roots just got swampy and the whole thing started to smell… not ideal when it’s right under your kitchen window.
Your denim trick sounds clever—never thought of that. I’ve just used old burlap sacks or even newspaper in a pinch, but denim probably lasts longer. I do wonder though, does it ever get too compacted over time and mess with drainage? Or maybe it breaks down just slow enough that you get a season or two out of it.
I get why people want to baby their plants, but honestly, most of mine seem happier when I just let them get on with it. Maybe plants want a little challenge?
I’ve actually tried denim as a liner a couple times, and yeah, it does get a bit compacted if you really pack in the soil or keep it super wet. What I’ve found works is laying it flat but leaving a little slack, so water can still get through before it gets bogged down. Usually lasts me a season or two—after that, it starts to break down and I just swap it out. Honestly, I think plants like a bit of airflow more than we give them credit for. Sometimes the simplest setups really do best, especially right under a window where you don’t want any weird smells drifting in.
That’s actually a clever way to use old denim. I hadn’t thought about leaving slack for drainage—makes a lot of sense. I agree on airflow, too. When I first set up my window boxes, I overcomplicated things with plastic liners and it just trapped moisture, which led to some funky smells and even a bit of mold. Swapping to something simpler (I ended up using burlap) worked way better for me. Plants really do seem happier with a bit of air moving around their roots.
I ran into a similar issue with plastic liners—thought I was protecting the wood, but all I did was create a swampy mess. It took me a while to figure out that plants really don’t like soggy feet. I tried poking extra holes in the bottom, but it still got musty. Eventually, I ditched the liner and just used a layer of gravel at the bottom, then some old cotton t-shirts (wasn’t sure about burlap at first). That combo seems to let water drain but keeps the soil from washing out.
Funny thing is, my neighbor swears by coconut coir liners, but they’re pricier than just reusing stuff you already have. I do wonder if there’s a big difference in how long they last or if it’s mostly just about airflow and drainage anyway. Sometimes I think we make these things more complicated than they need to be… Plants seem to thrive when you keep it simple and let them breathe.
I get what you’re saying about keeping it simple, but I’m not totally convinced gravel at the bottom actually helps with drainage. I’ve read a few times that it can just make water sit higher up in the soil, which isn’t great either. I tried it once in a couple of my boxes and still ended up with root rot—maybe it depends on the mix or how often you water. As for coir liners, they do seem overpriced, but I will say they last longer than cotton rags in my experience. I guess it’s all a bit of trial and error with these things.
Yeah, I’ve wondered about the gravel thing too. Tried it in a couple of planters last year and honestly, didn’t notice any difference—still got soggy soil when I overwatered. Some say it just creates a water table higher up, which kinda defeats the purpose. Coir liners are pricey, no doubt, but I’ve found they don’t break down as fast as other stuff. I guess sometimes you end up spending more just to avoid the hassle of replacing things every season.
- Gotta say, I’m with you on the gravel.
Nailed it—tried that trick in my own window boxes last year and all I got was a muddy mess... plus a few confused earthworms.“just creates a water table higher up, which kinda defeats the purpose.”
- Coir liners are steep, but at least they don’t rot out halfway through the season like those cheap felt ones. Nothing like pulling out last year’s liner and having it disintegrate in your hands.
- Honestly, half the time I’m more worried about water dripping down my siding than anything else. Good drainage is great, but not when it’s watering your window frames too.
Honestly, I’m always second-guessing the whole drainage thing too. Like,
That’s my worry every time it rains hard—can’t win! Anyone ever try putting a little tray underneath? Does that just make more mess?“Good drainage is great, but not when it’s watering your window frames too.”
- Totally hear you on the drainage dilemma.
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—that’s the catch, right?“Good drainage is great, but not when it’s watering your window frames too.”
- Trays can help, but if they’re not emptied or angled right, you might just end up with standing water and even more mess.
- I’ve seen folks use a layer of gravel in the tray to keep roots out of standing water, but honestly, it’s not a perfect fix.
- Sometimes it’s about finding that sweet spot—enough drainage holes, but making sure runoff gets directed away from woodwork.
- Don’t stress too much—trial and error is pretty normal with window boxes.
“Good drainage is great, but not when it’s watering your window frames too.”
That’s the real headache. I did a job last spring where the client’s old wood trim was basically rotting out because the box had way too many drainage holes and no plan for the runoff. We ended up running a little drip edge under the box, just enough to keep water from hitting the sill. Not fancy, but it worked. Gravel helps some, but yeah, it’s not magic. Sometimes you just have to tweak things until you find what works for your setup.