The only time I use a weed cloth is with a thick bark layer over the top, for pathways. Even with sterile shredded bark, the grass and dandelions will still take hold but pull out easily if they don't have a chance to breach the weed cloth. The absolute worse thing I did was try to use weed cloth as they advertise it - lay over raw soil, cut holes for plants, mulch over. What a nightmare that was for me.
