Mulching an apple tree has many benefits, like holding in moisture, improving soil structure, and increasing the fertility of the soil. But many people don’t follow the basic steps to properly mulch an apple tree.
To mulch an apple tree, apply 4-6 inches of wood chips in a circle about 4-6 feet in diameter around the base of the apple tree, and create a berm or donut around the outer edge, tapering down to 1 inch of mulch around the base of the trunk.
Benefits of Mulch Around Apple Trees
There are five main benefits to mulching around your apple tree.
- Hold in moisture – one of the most common benefits of mulching is to retain moisture around the base of your apple tree. This will conserve water, meaning you will need to water your tree less, and your tree will be able to survive through droughts for longer.
- Improve the soil structure – If you have clay soil, organic mulches can help break down the heavy clay soil over time and reduce compaction. Mulch will also improve the aeration, soil biology and drainage of your soil.
- Improve soil fertility – As organic mulches decompose, they add fertility back to the soil for the soil microorganisms and roots to take advantage of.
- Insulates the soil – Mulch will insulate the soil from the heat of the summer, which can burn the hair-like roots of the apple tree that grow right up into the top inch of soil. The added insulation will keep the soil cooler, which will also prevent the soil moisture from evaporating as quickly.
- Prevent weed and grass growth – Mulching around the base of your apple tree will prevent any weeds and grass from growing. Young trees need a competition free area under the base of the tree with no other vegetation in order to establish strong roots. Grass and weeds growing around the base of the tree will compete for nutrients and moisture with the fine feeder roots and will stunt the growth of young apple trees.
Best Type of Mulch for Apple Trees
Mulches fall into two categories, organic and inorganic. Organic mulches include any plant material like wood chips, straw, leaves, and grass clippings that will break down and provide nutrients and organic matter to the soil below. Inorganic mulches like crushed stone, pea pebbles, or lava rock will not break down, and will not add fertility or organic matter back into the soil.
For apple trees, it is best to use organic mulches that have not been treated or died, as they can leech into the soil and harm your apple tree. Here are a few types of mulches you can use around the base of your apple tree.
- Wood Chips or Straw – wood chips are the most common type of mulch because it is the most easily accessible. Arborist wood chips are the best type of wood chips and contain a mixture of small branches and leaves chipped into small pieces between 1/2 inch and 2 inches. Wood chip mulch can last 3-4 years before it completely breaks down and a thick layer 4-6 inches deep is great for preventing weeds and grass to grow through. As it breaks down, the wood chips will provide nutrients to the soil, and help improve the soil structure below. Straw will act similarly to wood chips, if that is all that is available in your area.
- Compost – compost is high in nutrients but is not the best mulch for apple trees. As weed seeds blow in they will easily sprout in the compost, and won’t do a great job at suppressing existing grass and weeds. Compost will also give the tree a large boost of nutrients, whether it needs it or not.
- Chop and drop – chop and drop includes pruned apple tree leaves and branches that are cut in place, and dropped around the base of the apple tree. Sometimes the best mulch is what is right in front of you. By using what you have available you won’t need to haul in a separate material into your yard. The leaves and branches of your apple trees are a great source of carbon to replenish the soil. Cut the small branches and leaves into smaller pieces with your pruners , and drop them on the ground around the base of the apple tree. Young wood will decompose quicker versus older wood. Be sure not to include diseased wood, dispose of that wood separately.
Other suitable organic mulches are ground tree bark, fresh or dried leaves, grass clippings, shredded newspaper or cardboard. All can be used based on their local availability.
Other mulches like living mulches or peat and pine needles are not recommended for apple trees. Voles love clover, so a living mulch of clover around the base of the apple tree will be an invitation for voles. Peat and pine needles are too acidic and should be avoided. They would change the acidity of the soil around your apple trees, and prevent your apple trees from absorbing the nutrients they require.
Sawdust is also not recommended around apple trees. The small particle size will quickly get matted, and will block oxygen and water from reaching the roots below.
How much mulch should I add?
In general, a layer of 4-6 inches deep is recommended. If your soil is well draining, a thicker layer will hold in more moisture. If your soil does not drain as well, a less thick layer will prevent the mulch from holding too much moisture, which can cause root rot.
How large of an area should I mulch?
For a newly planted young apple trees, a circle about 4 feet in diameter around the base of the apple tree will provide a good area for the surface roots of the apple tree to establish. As the tree grows larger, mulch should be extended out to the drip line.
The Proper Way to Mulch an Apple Tree
Now that you are convinced of the benefits of mulching and have decided on the type of mulch you will use around your apple tree, let’s take a look at some best practices for mulching apple trees.
If you have grass or weeds growing around the base of an established apple tree, cut as much as you can as close to the ground as possible. Use some cardboard or newspaper and lay that directly on the ground around the base of the apple tree within a 4-6 foot diameter circle. This will help smother out the remaining grass and weeds and prevent them from growing through the layer of mulch you are about to add.
Next, layer 4-6 inches of wood chips or your mulch of choice on top of the cardboard or newspaper. Use your hands to spread the mulch out evenly and create a donut, or berm, around the other edge of the circle. This will prevent water from draining away from the tree when it is being watered.
The mulch should taper down from the edge of the circle to the inside. Around the base of the trunk there should only be about 1 inch of mulch. Too much mulch around the base can hold in too much moisture and cause rot on the trunk and invite pests and diseases.
Avoid mulch ‘volcanoes’ which are excessive piles of mulch built up right around the trunk of the apple tree. You should still be able to see the root flare, and the graft union should still be 2-3 inches above the mulch.
DO NOT mix the wood chips into the soil below. The decomposition of the wood chips requires nitrogen, and as the wood chips break down, they will rob the apple tree of nitrogen. Any mulch should always rest on top of the soil, never mixed in with a rototiller.
Organic mulches that decompose faster should be re-applied more often. Wood chips will last 3-4 years, while grass clippings will only last about 1 year. Re-apply as required to keep the soil around your apple tree covered and competition free.
You should now have all the information you need to mulch a newly planted apple tree, or to fix the mulch around established apple trees.