Mulching is the placing of organic matter, such as straw or Lucerne, on top of your garden soil. It is good for vegetable beds as it adds vital nutrients and organic material.
However, continually mulching vegetable beds can have negative consequences, especially in cooler climate and higher rainfall areas. Knowing its shortfalls can help you maximise the benefits that mulch gives to your garden. Below is a comparison of the advantages and disadvantages of using mulch on vegetable beds and tips on when it is best to apply it.
ADVANTAGES OF MULCHING VEGETABLE BEDS
REDUCES SOIL EVAPORATION
This can reduce the need to water your vegetable beds by up to 70%.ADDS ORGANIC MATTER TO YOUR SOIL
Which provides valuable nutrients as this organic matter breaks down.ENCOURAGES EARTH WORMS
Encouraging earthworms is useful as they aerate the soil and provide fertiliser in the form of worm castings.REDUCES THE NUMBER OF WEEDS BY INHIBITING GERMINATION
Weed seeds may germinate but are less likely to break through the mulch layer.KEEPS THE SOIL UNDER THE MULCH COOLER
During high temperature periods in Summer having cooler soil reduces the risk of plant heat stress.
Mulch reduces evaporation, which makes it an ideal vegetable garden covering in the warm summer months.
DISADVANTAGES OF MULCHING VEGETABLE BEDS
REDUCES SOIL TEMPERATURE
Mulch retards the heating of the soil by the sun. In Summer this is not a problem but in early/mid Spring when you need all the warmth you can get from the sun’s rays it can inhibit the germination of seeds, especially those seeds that need a higher soil temperature to germinate. Lower soil temperature can also reduce the growth rate of seedlings.OFFERS GOOD COVER FOR SMALL SLUGS
Small slugs can bury themselves in the mulch layer during the day and emerge at night to feed.INCREASES THE RISK OF FUNGAL DISEASES
Mulch, especially when it is very wet, provides a good environment for fungal diseases (such as collar rot) to flourish.INCREASES THE RISK OF DAMAGE FROM SCRATCHING BIRDS
Birds like to scratch leaf litter because the soil is moister there, which brings worms closer to the surface. Mulch creates almost the same conditions as leaf litter.
Mulch retards the heating of the soil by the sun. In early/mid Spring a mulched bed can inhibit the germination of seeds, especially those seeds that need a higher soil temperature to germinate. Lower soil temperature will also reduce the growth rate of seedlings.
Because mulch retards soil temperature I practice what I call Seasonal And staged Mulching of Vegetable beds .
This involves applying no mulch from late winter through to mid-spring. As the weather warms up in spring I begin applying mulch, but only after planted seeds and seedlings have grown big enough (about 20 t0 25 cm high) to have mulch spread around their base without touching their lower leaves. But whatever the season I only ever sow seeds or plant seedlings into bare soil. For more information on this practice see: Seasonal And staged Mulching of Vegetable beds.
- All beds being fallowed are covered with a thick layer of mulch regardless of the season.
- Whatever the season I only ever sow seeds or plant seedlings into bare soil. (Applying mulch when the seedlings have reacted the height of 20 to 25cm.)
- In early winter I often apply a thin layer of mulch, but only around well established plants.
For more information see : Seasonal Staged Mulching Of Vegetable Beds.
MULCHING ADVANTAGES SUMMARY
ADVANTAGES
- REDUCES SOIL EVAPORATION
- ADDS ORGANIC MATTER TO YOUR SOIL
- ENCOURAGES EARTH WORMS
- KEEPS THE SOIL UNDER THE MULCH COOLER IN SUMMER
-
REDUCES THE NUMBER OF WEEDS BY INHIBITING SEED GERMINATION
MULCHING DISADVANTAGES SUMMARY
DISADVANTAGES
- REDUCES SOIL TEMPERATURE IN SPRING
- OFFERS GOOD COVER FOR SMALL SLUGS.
- INCREASES THE RISK OF FUNGAL DISEASES
-
INCREASES THE RISK OF DAMAGE FROM SCRATCHING BIRDS
