The summer of 2010/2011 was marked by high intensity rainfall and flooding in many parts of Queensland. Rainfall figures were double the long term average. Rivers and creeks filled with silt-laden water and many households and businesses were submerged. When the floodwaters subsided, a vile silty custard lay deposited amongst the debris of people’s lives.

Why try to prevent soil movement?
Prior to the floods, most people would not have given a moment’s thought to soil movement and how to stop it. When soil moves from your property you lose nutrients, organic matter, water-holding capacity and soil depth. These losses tend to be concentrated in the topsoil — the layer of soil most valuable for plant growth. Re-establishing lost top-soil is a hard-won process that is labour intensive and can be very expensive.

Other topics covered are:

• How does soil movement occur?
• How do I know if I have erosion?
• How can I prevent soil movement?
• Weeds won't work!

After record rainfall over much of northern Australia and other tropical and subtropical areas around the world, the lush growth in gardens has been astounding. As we start to head towards the cooler months, rain will finally start to become less heavy and less frequent, much to the relief of many gardeners.

Reassess, revise
Start planning for earthworks and building over the drier months. You will need to get your plans finalised and the contractors booked well in advance. Refer to our Classifieds in the magazine (page 97) for possible horticultural consultants, designers and landscapers.

With the memories of the rain and flooding still in our minds, it is time to look at how to improve our gardens so that they will fare better in future ‘big wets’. This may involve regrading parts of the garden so that water does not ‘flash flood’ or pond. During heavy rainfall drainage grates and field gullies block readily with debris and pipes often fail to cope with the water volumes from the runoff. Dispersing the water over a wide area and away from buildings and structures by regrading paving, paths, lawns or gardens will ensure that the water has a chance to get away.

Also have a think about encouraging infiltration rather than creating more runoff. Remember that runoff can wash away mulch and erode valuable topsoil, so where possible try to minimise this from happening. Consider replacing impermeable paved surfaces such as concrete and asphalt with gravel, permeable pavers, or preferably lawn and planting areas.

The article looks at:

• New Releases
• Improving the soil
• Vegetable garden
• Annuals

Special information is also provided for:

• Vegetable planting schedule for May, June and July
  for subtropics and tropics
• Annual planting schedule for May, June and July