Weed Fabric
Weed fabric comes in many shapes, sizes, and materials. In every case, it claims to suppress weeds. It often comes with guarantees that it will work (I think they know how few people will be cashing in on said “guarantee”). But here is a tried and true rule when it comes to weed fabric:
Don’t use weed fabric when you are putting organic material on top of it.
I have seen many people put weed fabric down on dirt, then cut X’s in the fabric for plantings, and then mulch over the fabric with whatever their preferred mulch is. We are usually called around two years later to do heavy weed cleanups in these beds, and even sometimes to pull the fabric out altogether.
Bottom-line: This strategy does not work in the long-term for at least these reasons:
(1) Weed fabric keeps mulch from doing its job.
Mulch breaks down. A lot of people do not like this because it means you have to buy more mulch, so they buy synthetic mulches made of rubber, plastic, etc. But the fact that it breaks down is essential for the health of your soil. The organic material is composting down into the soil, improving nutrition, oxygenation, and the microbiome. If there is a weed barrier between your mulch and the native soil, then your soil will not reap any of those benefits and the broken down mulch will become nice rich, compost that is a perfect home to… weeds!
(2) Weeds will grow out of those little X’s.
Those little X’s you made for plants are no longer blocking anything. The weeds will find this weakness, and you will find them bursting out at the bases of your desirable plants every spring, stealing away water and nutrients.
(3) It is a pain to add plants later
We’ve all been at the nursery and found a plant that we’d love to add to our flower bed. The problem is, you will need pull mulch aside and make new x’s for any plants you add. This is difficult to do without damaging the weed suppressing qualities of the fabric.
(4) Weeds grow where the seams of the fabric meet.
No matter how hard you try to fold, pinch, whatever, the weeds will find a way.
When is it a good idea to use weed fabric?
Weed Fabric does work when you are creating a barrier between soil and hardscape material. If you are making a path with stepping stones and gravel in between the stones, you would definitely do well to lay weed fabric underneath. This is because weeds cannot grow in rocks, and they can grow in dirt. By using weed fabric, you separate the fertile material from the infertile, and thus have much better chances at not having weed growth.
All that said: I do not use weed fabric, even in hardscapes. I hand-pull weeds in softscapes, and I burn weeds in hardscapes with a weed torch. Don’t let weed fabric lure you into a false sense of weed security - the only true weed defense is a gardener’s vigilant hands.