Gardening experts explain exactly when you should add mulch to your garden in autumn.Credit: Erica George DinesKey PointsMulch in late autumn, after the first frost but before the ground freezes.Organic mulches like wood chips or straw insulate soil, suppress weeds, and add soil nutrients.Keep mulch away from plant stems, and combine it with slow-release fertilizers or compost.Though mulch can be applied at different times of the year, mulching …