You’ve probably seen mulch in flower beds, vegetable gardens, paths, and landscaping. But do you know how to fertilize your lawn with mulch? Organic mulch can decompose and provide a nutritional boost to your turf, just like fertilizer. The best part is that you can create many of these mulches at home or purchase them at your local garden center.
What is mulch?
Mulch is any organic or inorganic material spread on the soil surface to enhance or protect it. For example, mulch can preserve moisture or prevent weeds.
Organic mulch is made of plant-based materials that can decompose, like grass clippings and leaves. Inorganic mulch comprises materials that don’t decompose, such as rocks or landscape fabric.
Since inorganic mulch doesn’t decompose, it isn’t helpful in lawns. It’s mostly beneficial in decorative situations like flower beds or areas where you want to control growth (such as around an ornamental plant). It also can look nice lining your lawn, contrasting it with the surrounding landscaping.
Organic mulch can provide benefits that inorganic mulch can’t, introducing yummy nutrients into the soil. When applied correctly, it can be just what your grass needs to grow lush and healthy.
Steps to fertilize your lawn with mulch
Fertilizing your lawn with mulch as a soil amendment involves incorporating organic materials into the soil to improve its fertility, structure, and water retention capabilities. Here’s a step-by-step guide on how to go about it.
When to fertilize your lawn with mulch
The timing for applying mulch to your lawn depends on the type of mulch you’re using, your climate, and the specific needs of your lawn. In general, there are two primary seasons for applying mulch to lawns:
- Spring: Mulching in spring helps suppress weeds, improve soil moisture, and regulate soil temperature as the growing season begins. It also can boost curb appeal. Before you start, ensure the soil has thawed and is not excessively wet. Applying mulch too early in spring when the soil is still frozen or waterlogged can cause moisture-retention problems, attract fungal diseases and pests, and contribute to root rot.
- Fall: This is an excellent time to apply mulch to your lawn. It helps protect the grass roots during the winter, retains soil moisture, and provides insulation against temperature extremes. Apply mulch in late fall after the grass has gone dormant but before the ground freezes. This allows the mulch to establish a protective layer for the winter.
How to fertilize your lawn with mulch
- Prepare the soil
Remove debris, weeds, and rocks before applying mulch to create a more hospitable environment for it.
- Prepare the lawn
Mow the lawn to the desired height and remove any thatch. Aerate the soil to enhance the effectiveness of mulch and allow its nutrients to penetrate it better.
- Choose the right mulch
Select one of the nutrient-rich, organic mulches outlined in detail in the section “Best types of mulch for your lawn.” As they break down over time, they release important nutrients into the soil. Some excellent options include:
- Grass clippings
- Shredded leaves
- Compost
- Pine needles
- Straw
- Apply the mulch according to your grass’ needs
In spring, when you’re mulching to prepare your grass for the growing season and maintain healthy soil, a thin layer of ½ to 1 inch is enough. In fall, when mulching is primarily done to protect grassroots during the winter and provide insulation, you can apply a slightly thicker layer of around 1 to 2 inches.
- Reapply as needed
Mulch breaks down over time, so monitor the thickness of the mulch layer and reapply as necessary. One thing to remember: Too much mulch could smother your grass and prevent air, water, and nutrients from reaching the soil, so don’t overapply.
- Water after application
Water the mulch with 1 inch of water after applying to help it settle and start the decomposition process. This also aids in nutrient release and improves soil moisture retention. Check the soil periodically and make sure it stays damp, not wet. If it feels dry to the touch, it’s time to water.
- Turn mulch piles regularly
This process helps the organic matter decompose evenly and receive proper airflow, prevents compaction, weeds, and diseases, and keeps the mulch fresh. Due to a speedier decomposition process, you’ll need to do this more frequently in hot and dry conditions. In wet or cold conditions, turning won’t be needed as often. Use anything from a rake and pitchfork to a garden shovel or spade for this task.
- Monitor your lawn and plants
Keep an eye on the health of your lawn and plants. Regularly inspect them for signs of nutrient deficiencies or excesses and adjust your mulching practices accordingly. Organic mulch can harbor mold, fungi, and pests, especially if it’s too thick or damp. Remove the affected mulch if you see these problems. You don’t want to accidentally spread them on your grass.
- Combine with other amendments (if applicable)
For a more comprehensive approach to soil fertility and health, consider combining mulch with other soil amendments, like organic fertilizers or lime, based on the specific needs identified through soil testing. Some good organic fertilizers include animal and green manure, bone meal, wood ash, and cover crops such as vegetables.
Best types of mulch for your lawn
Here’s a list of organic mulch types that will decompose in your yard and provide your soil with those aforementioned yummy treats.
Grass clippings
Macronutrient ratio: 4% Nitrogen, 0.5% Phosphorus, 2% Potassium
Grass clippings are an easy, affordable way to mulch and fertilize your lawn. You may have heard that grass clippings contribute to thatch buildup, but that’s just not the case. Thatch is only caused by living and dead roots, shoots, and stems that accumulate on the soil surface. Lawn clippings, on the other hand, quickly break down and feed your soil.
Remember to clean excess clippings off curbs, gutters, and storm drains. Loose clippings could negatively impact water quality if they wash away.
That said, you shouldn’t use grass clippings as mulch if they’re:
- Too long (more than 1 inch)
- Wet
- Clumping together (they could suffocate the lawn)
- Diseased
Pros of grass clippings as lawn mulch:
✓ Decompose rapidly
✓ Reintroduce nutrients such as nitrogen, phosphorus, and potassium into the soil
✓ Improve soil texture and quality
✓ Introduce more organic matter into the soil
✓ Can prevent the appearance of weeds
✓ Conserve moisture
✓ Moderate soil temperatures
Cons of grass clippings as lawn mulch:
✗ Can look unattractive
✗ Have poor compaction resistance
✗ Could spread disease
✗ Won’t work when grass clippings are too long or wet
✗ Can negatively impact water quality if they end up in gutters or storm drains
✗ Can contain weed seeds, spreading them further on your lawn
Shredded Leaves
Macronutrient ratio: 0.5% Nitrogen, 0.1% Phosphorus, 0.5% Potassium
Thinking of raking up those fallen leaves? Don’t do it just yet. You can fertilize your lawn with them if you cut them up with a mulching lawn mower or shredder. As with grass clippings, you can use extra leaves to mulch other plants.
Mulching leaves from different plants may have various effects. For example, oak and beech leaves are acidic, affecting your soil’s pH when decomposing. Soil pH measures acidity and alkalinity. A pH that’s too high or too low could affect your lawn’s ability to absorb nutrients (most grass types prefer a pH of between 6.0 and 7.0).
Get a soil test to see where your pH stands and whether acidic leaf mulch would help or harm your lawn. To adjust your soil’s pH levels, it’s probably best to rely on soil amendments.
Pros of shredded leaves as lawn mulch:
✓ Easy to get and inexpensive
✓ Decompose quickly
✓ Provide shelter for beneficial insects in winter
Cons of shredded leaves as lawn mulch:
✗ They could blow away if not properly shredded
✗ Have poor compaction resistance
✗ Can make soils more acidic
✗ Can suffocate the grass if wet
✗ Can spread diseases
✗ Can attract rodents
✗ Can be a fire hazard
Compost
Macronutrient ratio: 2% Nitrogen, 1% Phosphorus, 2% Potassium
If you like the idea of recycling plant waste, then compost is the solution for you. You can make compost from table scraps, leaves, and grass clippings. Don’t use meat, bones, fatty foods, diseased plants, weeds, or animal waste.
Not only will composting help you prevent waste, but your lawn and other plants will get a nutritional boost. If you don’t want to make your own compost, you can simply buy it at your local garden center.
Pros of compost as lawn mulch:
✓ Improves soil structure
✓ Improves water retention and nutrient capacity in sandy soils
✓ Increases drainage in heavy clay soils
✓ Suppresses weeds
✓ Regulates soil temperature
✓ Reduces the need for chemical fertilizers
✓ Breaks down rapidly when applied
✓ Releases nutrients slowly, meaning there’s no fertilizer burn
✓ Protects plant roots
✓ Prevents diseases
✓ Reduces the need for aeration
Cons of compost as lawn mulch:
✗ Attracts wildlife
✗ Can produce odor
✗ Requires time to break down before you can use it
✗ Not as good at suppressing weeds as other mulches
Pine needles
Macronutrient ratio: 1% Nitrogen, 0.05% Phosphorus, 0.2% Potassium
Do you have a pine tree in your yard? Those fallen needles also make excellent mulch for lawns. Break them down using a shredder, or toss them in your compost pile. If you decide to compost them, make sure they make up less than 10% of your compost pile.
You may have heard that pine needles make the soil acidic. According to the Oregon State University Extension, this is a myth. Pine needles are acidic when they fall from the tree but neutralize as they decompose, so you shouldn’t see any significant pH changes when using them.
Pros of pine needles as lawn mulch:
✓ Inexpensive or free
✓ Visually appealing
✓ Stay in place
✓ Air, water, and nutrients penetrate easily
✓ Smell good
✓ Resist compaction
✓ Have a long lifespan
Cons of pine needles as lawn mulch:
✗ Can be a fire hazard
✗ Prevent water infiltration if the layer is too thick
Straw
Macronutrient ratio: 0.5% Nitrogen, 0.2% Phosphorus, 0.2% Potassium
Hay is for horses, but what about straw? While straw has many uses, you can use it as mulch for lawns and other landscaping. It works especially well on newly sown lawns. While it’s accessible and inexpensive, make sure you purchase it from a reputable seller. Straw can contain weed or grain seeds that could sprout on your lawn, ruining its appearance.
Pros of straw as a lawn much:
✓ Resists compaction
✓ Regulates soil temperature
Cons of straw as a lawn mulch:
✗ A thick layer provides hiding places for pests
✗ A thin layer could blow away
✗ Decomposes rapidly, meaning you need to replace it more often
✗ Highly flammable
✗ Not visually appealing
FAQ about fertilizing your lawn with mulch
Is mulch the same as regular lawn fertilizer?
Not exactly, though they do overlap. Fertilizer is any organic, inorganic, natural, or synthetic material that provides the nutritional elements needed for plant growth. This means that mulch can be a fertilizer if it supplies nutrients. However, mulch that is only decorative or prevents undesirable plant growth isn’t fertilizer.
Do I have to remove old mulch before applying a new layer?
Unless the old layer of mulch is too thick, and you want to avoid suffocating your grass, you don’t have to remove it completely. However, it’s a good idea to loosen it up and give it a good mix to prevent compaction, which occurs when the layer becomes too dense and tightly packed.
How do I know if I need additional fertilizer beyond mulch?
If mulch isn’t cutting it for your lawn, and your grass is turning yellow or not growing as it should, you may have to consider investing in additional fertilizer. Remember to choose based on your soil’s needs, your grass type, and the climate.
What benefits does a mulching lawn mower bring?
Mulching lawn mowers chop grass clippings into small pieces and leave them on the lawn, contributing to proper grasscycling, enhancing soil health, and reducing the need for fertilizers. Besides that, you won’t have to bag or rake grass clippings or deal with as many weeds, saving time, money, and effort in the long run.
Top-notch help is within reach
If you’re facing serious challenges with your lawn and DIY fertilization just isn’t working for you, consider contacting a local pro for dedicated help. They can fine-tune their services to align with your individual needs and enhance the beauty and health of your lawn at the same time.
Main Image Photo Credit: Public Domain Pictures
