How Much Wood Chip Should I Apply and When?

The amenity wood chip supplied by Gristwood and Toms is typically aged for about 3 months, which gives it a rich and attractive brown colouring. We recommend beginning mulch application before annual weeds become established. You should ideally mulch bare soil as soon as practical, especially in the spring and autumn when weeds are most likely to germinate. While you can apply mulch at any time, be careful in Spring not to heap mulch on top of emerging and growing plants. Autumn is ideal after herbaceous plants have finished, when the soil is damp but still relatively warm.

For the best results, wood chip mulch should be deep enough to suppress weeds and inhibit light to the soil surface: research has demonstrated that weed control is directly linked to mulch depth, as is enhanced plant performance. In fact, shallow mulch layers may promote weed growth and/or require additional weed control measures. We recommend at least 75mm depth for ornamental sites.

Remember, do not to pile mulch against the trunks of shrubs and trees. This creates a dark, moist, low oxygen environment. Piling mulch on the trunk provides exactly the right conditions for fungi to enter the plant. Taper the mulch as you approach the trunk and this doughnut-shaped application will protect the soil environment as well as plant tissues above ground.

Once the mulch is applied, little management needs to be done other than reapplication to maintain minimum depth. Churn up the existing mulch first before adding a renewal layer. High traffic areas are most likely to need replacement.