Mulch is a vital component of any healthy garden. A layer of mulch helps retain moisture prevent weeds, and regulate soil temperature. But when’s the best time to apply mulch – spring summer, or fall? Can you mulch in the summer or is it better to wait until cooler weather?
Mulching in the summer can provide benefits, but it also has some potential downsides. Let’s look at the pros and cons of summer mulching so you can decide if it’s right for your garden.
The Benefits of Summer Mulching
Mulching during the summer growing season offers these advantages
-
Conserves moisture – Mulch prevents evaporation, helping soil retain moisture longer. This reduces watering needs.
-
Suppresses weeds – Mulch forms a physical barrier that blocks light stopping weed seeds from sprouting. It also impedes established weeds.
-
Moderates soil temperature – Mulch keeps plant roots cooler, preventing heat stress on hot days. It also insulating from extreme cold.
-
Prevents erosion – Mulch binds the soil surface, preventing rain and irrigation from washing soil away.
-
Adds organic matter – As it decomposes, mulch incorporates organic material into the soil, improving texture and fertility.
-
Protects shallow roots – Mulch buffer tender plant roots from mechanical damage by gardening tools and foot traffic.
If your beds are unmulched, applying summer mulch provides all these benefits at a time when plants are actively growing. It boosts the garden environment when you need it most.
Potential Drawbacks of Summer Mulching
However, summer mulching also has some risks and disadvantages:
-
Can foster disease – Warm, humid conditions under summer mulch can allow fungal diseases like mildew to develop. Select disease-free mulch.
-
Attracts insects – Fresh mulch provides ideal habitat for some pests like ants and earwigs. Let mulch age before applying.
-
Encourages weeds – Summer heat speeds decomposition, allowing more light through mulch. This grows more weeds.
-
Causes nitrogen depletion – Decomposing mulch ties up soil nitrogen. Supplement with extra fertilizer to prevent deficiency.
-
Can dry out plant crowns – Piling mulch too high around plant stems leaves crowns exposed, causing desiccation.
-
May suffocate plants – Excessive mulch depth deprives roots of needed air circulation. Limit to 2-3 inch depth.
-
Can become matted – Summer rains and irrigation cause finely shredded mulches to compact and mat together, reducing effectiveness.
With some precautions, these potential issues can be avoided. But summer mulching requires more attentive maintenance than spring or fall applications.
Ideal Time to Apply Mulch
While summer mulching can be helpful, the optimum time for mulching is typically early spring. Here’s why:
-
Soil warming – Spring mulch moderates soil temperature, preventing premature warming that stresses plants.
-
Weed prevention – Applied before germination, spring mulch greatly reduces summer weeds.
-
Moisture retention – Mulch applied before dry weather begins maximizes its moisture conservation abilities.
-
Nutrient conservation – Spring mulch prevents nutrient loss from erosion and leaching during rainy periods.
-
Pest deterrence – Cool, stable spring mulch environments discourage pests like ants that favor heat and humidity.
-
Better decomposition – Spring mulch decomposes slowly, providing a more stable cover through the growing season.
-
Drought protection – Mulched spring beds better withstand hot, dry conditions if drought occurs.
While spring is preferred, it’s certainly fine to mulch beds anytime needed during the growing season. Just be attentive to proper mulching practices.
Practical Tips for Summer Mulching
Follow these guidelines to get the most from summer mulching:
-
Choose coarse mulch – Larger particles resist matting and decomposition better than fine shredded material.
-
Limit depth to 2-3 inches – Shallow layers prevent matting while still providing benefits.
-
Leave space around crowns – Keep mulch a few inches away from plant stems and trunks for air circulation.
-
Use aged mulch – Stockpiled mulch less likely to contain insects, weeds, or diseases.
-
Spread evenly – Uniform layers look neat and maximize functionality. Feather edges.
-
Replenish old mulch – Freshen thinning, matted mulch by topdressing with a thin new layer.
-
Apply fertilizer – Counteract nitrogen depletion by feeding plants, especially heavy feeders.
-
Check drainage – Ensure beds aren’t collecting excess moisture beneath mulch after heavy rains.
-
Control weeds – Pull emerging weeds before they take hold. Spot treat with herbicide if needed.
Ideal Mulching Materials for Summer
All types of organic mulches can be used in summer, but certain materials perform best:
-
Wood chips – Shredded hardwood chips resist compaction although they decompose faster. Avoid pile ups around plants.
-
Pine bark nuggets – Larger pieces provide great insulation. Allow deep layers up to 4 inches.
-
Shredded bark – Fines between nuggets resist matting. Need occasional topping off.
-
Pine straw – Lightweight and excellent at suppressing weeds. Scatter new bales thinly over old.
-
Leaf mulch – Deciduous leaves make great summer mulch but avoid piling deeply.
-
Compost – Excellent nutrient source but compacts readily. Mix with bulkier mulch.
-
Gravel – Provides great weed and moisture control. Top dress to refresh. Avoid plastic underlayer.
-
Newspaper – Sheets covered with mulch block weeds. Use soy-based inks.
-
Cardboard – Effective barrier when topped with mulch, but unsightly. Not for perennial beds.
-
Landscape fabric – Woven fabrics work under mulch but need maintenance. Avoid plastic sheet.
With proper selection and application, mulch can give your garden an extra boost during the hot summer months. Just be vigilant about good mulching practices to keep the beds healthy and weed-free.
Mulch Your Beds In Summer
Mulching of the planting beds is a very important item from a horticultural aspect that is often overlooked. In addition to making your yard look better, mulching the beds is good for the plants and animals that live there.
- Over time, mulch breaks down into plant-food nutrients that seep into the soil and reach plants through their roots. Mulch is like a 3″ layer of full plant food.
- Prevents loss of water from the soil by evaporation.
- When applied deeply enough to stop weeds from sprouting or to suffocate existing weeds, it slows their growth.
- It keeps the soil cooler in the summer and warmer in the winter. This keeps the temperature more even and helps roots grow, which leads to better growth and blooms.
- Stops soil from splashing, which stops erosion and keeps diseases that are in the soil from splashing up onto the plants.
- Mulches can improve the soil structure. As the mulch decays, the material becomes topsoil. Decaying mulch also adds nutrients to the soil.
- Keeps the soil’s surface from crusting over, which makes it easier for water to get into the soil and move around in it.
- Shields tree and shrub trunks from damage by lawn equipment
- Helps prevent soil compaction.
- Plants with mulch have more roots than plants that don’t have mulch around them. This is because mulched plants grow more roots in the mulch around them.
- Mulch also makes it possible to pull weeds while their roots are still growing in the mulch. This way, the roots don’t go into the soil and break off and grow back.
Even if you don’t have any plants in your beds, mulch will still help because it breaks down into nutrients that will improve the soil. In the Illinois town of Crete, 3 inches of hardwood mulch turned 1 inch of clay soil into usable, nutrient-rich soil in just one year.
There is one draw back to hardwood mulch. It needs to be top-dressed every couple of years, depending upon how much mulch is installed. As a general rule, you should put down and keep up a level of about 3” to 4” of mulch at all times. This should cover you for two seasons. We can put 2 inches of mulch in all the beds, though, to save money. This would give the plants a good start, but it might not last as long.
Possible Problems When Mulching
Artillery Fungus Occasionally, the naturally occurring micro-organisms in cellulose mulches can become a
nuisance. The shotgun or artillery fungus (Sphaerobolus) may cause serious problems. While it decays the mulch, it also produces fruiting structures that resemble tiny cream or orange-brown cups that hold a spore mass resembling a tiny black egg (1/10 inch in diameter). This fungus shoots these spore masses high into the air. They stick to any surface and resemble small tar spots on leaves of plants, on cars or on the siding of homes. To avoid damage, Suburban Landscaping does not use mulches that contain cellulose (wood), we use pure bark mulches.
Another type of fungus that can be a problem is slime mold. It looks like an unsightly bright yellow or orange slimy mass that can be several inches to a foot or more in diameter. They are harmless but unsightly, with some fungi producing toad stools (mushrooms).
Although highly unlikely to occur, these fungi can arise every once in a great while. We buy our mulch in such large amounts that if there is a fungus, we will find it in our stock pile and get rid of it long before a customer would have noticed.
Mulching in Summer
FAQ
Is it okay to mulch in July?
When should you not mulch?
Is mulch good for summer?
Can you put mulch down anytime?
