How to mulch food forest trees and shrubs

If weed pressure is not a big issue, (you’re dealing with bare soil, the site is weed-free…) or you are just replenishing mulch around your woody perennials I suggest simply topping up with bulky organic materials which don’t contain weed seeds.

How to mulch around your trees and shrubs:

Estimated time: 10 min per tree/shrub

STEP 0: Finish all your soil prep

• If applicable, before laying down the mulch finish all your site grading and other soil preparation work.
• Add soil amendments such as Azomite, kelp meal, rock phosphate, granite meal, and gypsum (a pound/0.5 kg contributes a wealth of minerals).

STEP 1: Lay down the mulch

• Apply at least 10 cm of mulch, with a minimum diameter of a meter for each tree/shrub.

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In case of high weed pressure (aggressive weeds, planting into pasture or grasses…) in addition to the organic mulches above you’ll need to add a sheet layer as a weed barrier. The sheet layer is critical to the successful growth of your trees and shrubs as it prevents or at least greatly slows the growth of any weeds surviving in the ground or sprouting in the seedy mulch.

In sheet mulching you essentially build layers of mulch where you: 1) lay the weedy mulches down first, 2) then cover them with a layer of biodegradable sheet material to prevent weed growth, and 3) put the weed-free mulches on top. This sheet mulch should kill grasses in 3-4 months, although some perennials may take longer to kill.

How to sheet mulch around your trees and shrubs:

Estimated time: 30 min per tree/shrub

Note: Try to mulch to a minimum diameter of 3 feet ( 1 meter) for each tree. Total mulch depths can range from 3 to 9 inches (8-23 cm) when first applied, with deepest mulches on extreme sites. For weed control, you need at least 3 or more inches (5-8 cm).

STEP 0: Finish all your soil prep

• Before sheet mulching, finish all your site grading and other soil preparation work.

STEP 1: Cut the existing vegetation

• Make sure to cut the grass or weeds hard, right into the ground. This will shock them and also reduce their reserves for resprouting.

STEP 2: Add soil amendments (if necessary)

• Add soil amendments such as Azomite, kelp meal, rock phosphate, granite meal, and gypsum (a pound/0.5 kg contributes a wealth of minerals.)

STEP 3: Water abundantly

• If you can irrigate heavily before laying down your mulches, this charges the soil with water. Otherwise, do your mulching after the rain.

STEP 4: Cover with a biodegradable sheet

• Next lay down your weed barrier to block all light to the soil below.

• Make sure that every seam between pieces of your biodegradable sheet overlaps at least 4 in or 10 cm or more (this makes it more difficult for plants to find their way to the surface before their energy runs out).

  Note: If you’re using newspaper or cardboard, wet them and put down a thick layer (newspaper: six sheets thick, plus overlap, cardboard: three sheets thick, plus overlap)

 

STEP 5: Pile up the weed-free mulch(es)

• Place the weed-free mulches on top of the sheet layer.

• The key here is to have enough weed-free mulch to cover the sheet layer by at least 1 in/3 cm.

• Ideally, you would pile up fungal compost or woody mulch (chipped bark, wood chips, ramial wood chips) anywhere from 2-8 in/ 5-12 cm deep.

  Note:

  1. Always keep mulch off the stem of the tree; the organic mulches right up against the trunk of the tree will retain too much moisture.
  2. If your final layer is compost, cover it with straw to avoid direct sun exposure.

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