Nathan Parker 

Tree roots have infiltrated my raised garden beds. I've fought them for years, to defend my summer tomato plants, but it has become increasingly futile. It's more roots than dirt now. Twisted and evil. This weekend I dug it all out, both to hack through the roots but also to lay down some landscaping fabric at the bottom. I'm not sure this is a cure since tree roots are so pernicious and persistent -- they may find a way through my defenses. But I hope it slow them down for a few years. It'll also reduce the number of entry points, so I can more easily spot them and tear them out once the get in.

This was nominally a weekend home project (which involved shoveling 5,000 lbs of root-infested dirt, twice. My back thanks me). But, it felt reminiscent of my day job, which is fighting web abuse at scale... Attackers are motivated to find the gaps and they keep trying till they do. Slowing them down is worthwhile, and constraining them to known conduits help you catch them and rip them out more reliably.

Mar 20, 2023 at 3:08amWeb
Show threadNathan Parker Mar 20, 2023
I also threw down some old redwood fence boards on top the the fabric, because, defense in depth. I still have to leave gaps for drainage, so it's not a hard security boundary. OH and I should mention I already had chicken wire under it all to keep the moles from coming up, and elaborate cages goes on top to keep the squirrels and neighborhood rats out. These tomatoes really are attacked from all directions. But I will persist.
Show threadAnnaleeMar 21, 2023

@parkern airgap the beds. It's the only way to be sure.

(this is Very Helpful now that you've already moved all the dirt twice).

Show threadNathan Parker Mar 21, 2023
@Annalee yeaaa, I realized airgapping would be more effective, but that required materials I didn't have, and wouldn't fit in the 8 hrs without rain I had on the weekend. So I avoided the feature creep, but we'll see about the root creep.
Show threadNathan Parker Feb 24, 2025

@Annalee So... I've determined my defense efforts bought me two years. I did some excavating today and alas the roots have finally punctured the landscaping cloth and wended between the boards. This is correlated with a BUMPER tomato crop in 2023 (no roots), and a so-so crop in 2024 (some roots).

I'm contemplating either, a) digging a 3' deep trench around the beds and placing some vertical 80 mil plastic root barrier ("Bamboo Shield"). Or, b) tearing out these beds and replacing them with 300 gal horse troughs on cinder blocks. The latter is harder to retrofit with squirrel-cages like I've built for these wooden ones.

It seems that 90% of my gardening effort is just defense.