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SHS Garden Journal Blog

Effects of Recent Wet Weather on Your Garden

Tuesday, March 19, 2013

We have noticed some changes in our garden beds and plants over the past few weeks, as a result of the high rainfall experienced in Sydney. You may be experiencing similar issues in your garden:
  • Waterlogged soil.
  • An increase in garden pests and diseases - e.g. snails, slugs and curl grubs.
  • Plants showing signs of stress.

What's going on in the soil?

Too much water in a garden bed can affect the growth and health of our plants particularly if the rainfall is prolonged. This is due to the lack of oxygen and nutrients in the soil which will promote an anaerobic environment rather than the normal healthy aerobic environment. 

A lack of oxygen will decrease the levels of beneficial soil micro and macro organisms, as they require oxygen to survive. Extra water in soil also changes its structure minimising airflow, further contributing to an anaerobic environment.  In healthy soil airflow and nutrients will circulate between the small spaces in soil particles, making its way to our plant roots.

Soil types can enhance these problems in wet weather:

Clay soil can become compacted restricting the flow of oxygen to your plant roots and soil life – this may lead to root rot where plants will wither and die.

Sandy soil can allow too much drainage leading to soil erosion and depletion of nutrients available to plants – plants becoming lacklusture and the yellowing of leaves.

Steps to support your plant and soil life during times of increased rain are:

  • Good drainage – being aware of your soil type and using compost, manure, mulch, grass clippings, green manure crops strengthening soil structure to minimise compaction and erosion. Avoid leaving plants sitting in pools of water.
  • Add organic matter to the top layer of your soil e.g. compost.  The humus will act as a sponge in the soil absorbing excess water, regulating the dispersal of water, promoting resilience, soil life and structure.
  • Use mulch to protect the soil from erosion and heavy rainfall.  Mulch will help to insulate the soil and provide protective habitat for beneficial microorganisms and soil life.
  • Using worm juice and a sea or fish emulsion (e.g. seasol) on your garden plants to promote plant resilience, nutrient balance and health.
  • Promote airflow in the garden by spacing garden plants, using trellis where needed to lift plants off the soil and removing rotted or dead plants. Harvest plants regularly to allow for new growth and airflow.
  • Garden pond – build a pond on the highest part of your garden to collect excess water and provide a habitat for beneficial predators e.g. dragonflies, frogs, etc that will feed on the garden pests that thrive in wet weather.
  • Curl grubs are very destructive to your garden plants and lawn as they eat away at the roots. They are best removed manually by hand and fed to chickens or disposed of thoughtfully. Attracting native birds to the garden will help to keep them at bay, as birds like to eat them too.
  • Snails and slugs can be kept away by using crushed eggshells around your garden plants. The crushed eggshells are a rough surface that snails and slugs are sensitive too when trying to crawl over. Chickens and birds like to eat snails and slugs too, when you see any of these pests collect them by hand and feed to chickens or birds.