Succulent plants such as Kalanchoe thyrsiflora cope with limited watering

The recent confirmation of another El Niño event after three rainy summers that had lulled us Sydney gardeners into a false sense of security has focused my mind on getting my garden ready for the onslaught. We have already had the hottest September days on record this year, a firm harbinger of what may lie in store for us; and this Sunday, the first day of October, has been another scorcher, with a temperature of 36 degrees and hot, dry winds.

Sugar cane mulch (at left) is a good cover for exposed soil

Sugar cane mulch (at left) is a good cover for exposed soil

The traditional practices to prepare gardens for a hot summer bear repeating: apply a soil-wetting product in autumn and spring so that any available moisture will be drawn downwards into the ground, then cover the exposed earth with an organic mulch, such as sugar cane mulch, rough compost, straw or lucerne, to help keep moisture in by providing a barrier to evaporation caused by heat and wind. Pine bark or wood chips can be useful in areas with established shrubs and trees, but I think finer material is better around smaller plants.

Mulch is best applied when the ground is damp and should be laid a few centimetres thick, but is best kept away from the trunks of trees and shrubs and from the stems and crowns of perennials and annuals. Organic mulches will eventually break down to increase the organic content in the soil, which further helps to retain moisture. Mulch also deters many weeds from growing and competing with your plants for water and nutrients.

Water in the early mornings: the former garden of Sandra Wilson in Sydney

Water in the early mornings: the former garden of Sandra Wilson in Sydney

Giving infrequent, deep soakings is better overall for the garden than frequent, shallow ones, which only encourage the roots to come to the surface of the soil. This can lead to damage to the roots if the soil then dries out. It is best to water in the early mornings rather than the evenings (which can promote fungal diseases due to foliage staying wet all night) or in the heat of the day, when much moisture can be lost by evaporation. Watering in the morning hydrates the plants for the hot day ahead. Spraying plants with an anti-desiccant product can be helpful to reduce water loss on hot and windy days.

Pipe in a dripper system in my garden

Pipe in a dripper system in my garden

A drip watering system can be very useful to keep your garden (and pots) irrigated. If you already have one installed, check now that it is functioning properly and watering the garden as you want it to, as drippers can get blocked up and fittings can perish over time. You may wish to consider installing a grey water system: either a simple extension of a hose from a washing machine - or a complete plumbed-in setup with a storage tank and dripper hoses through garden beds. We installed one about four years ago, and it has been very helpful for a difficult area under some big trees. Putting in a water tank is another idea to contemplate, and it can be a boon if watering restrictions come in again. It can be a good idea to group your plants in different areas according to their watering needs, so that some areas don't need as much water as others.

Many gardeners swear by the use of a seaweed extract to help plants cope better with the stresses of heat and drought, and I have been a convert in recent years. It can be applied every few weeks to plants in borders as well as potted plants. It always feels as if I am doing some good to my plants by giving them a dose of seaweed extract - maybe it's a placebo effect (do plants respond to placebos??), but I am going to keep on with it!

Dietes White Tiger, Alternanthera Little Ruby, Limonium perezii and lavender are tough plants in the garden of Carolyn Hughes in Sydney

Dietes White Tiger, Alternanthera Little Ruby, Limonium perezii and lavender are tough plants in the garden of Carolyn Hughes in Sydney

Plant choice is an important aspect of navigating hot summers. Whilst I wouldn't really advocate much planting from now on, as plants will not establish as well as if they were planted in autumn and winter, it is worth keeping tabs over the coming months as to which plants are holding up best to heat and drought. A recent blog looked at a garden with a challenging area, which made some plant suggestions. Trial and error is probably the only way to find the troupers that will cope. I have less patience these days with plants that need more than their fair share of water. It can be good to share notes with other gardeners in your areas; a few years ago, our garden club surveyed members for 'summer survivors' and compiled a little guidebook, which has proved very useful.

I have recently been interested in looking for some other ways to tackle the effects of summer heat on the garden. One idea is to provide temporary shelter from the sun over garden areas in summer, using 50% white shade cloth rigged up on poles. This shade cloth allows diffused light through without a buildup of heat beneath. This stops the burning effect of the sun directly on plants and lowers the ground temperature, reducing evaporation and transpiration. This technique provides an alternative to the old sheets that I sometimes throw over vulnerable plants during heatwaves!

An olla

An olla

Another interesting idea is the use of an 'olla', an unglazed terracotta vessel that is buried in the ground (or in a large pot) with its neck extending above the soil, and filled with water, allowing a slow release of moisture to plants as they need it. It is an ancient method of irrigation that has recently made a comeback and I am keen to try it!

Swales and rain gardens are interesting ways to help water infiltration into the soil when rain does fall, and we can expect storm events over summer as well as heat! A swale is a ditch used to harvest and distribute rainwater along a horizontal plane across a slope so that it doesn't rush away off the property but instead can seep gradually into the soil. The basic anatomy of a swale consists of a shallow channel on a slight slope lined along with a mound on the downward side - called a berm - to keep the water in. Both sides of the swale must be covered in plant life to prevent soil erosion.

A rain garden is similar in concept but once the ditch is dug, gravel and sand layers are placed at the base of it then amended soil placed on top, which is then planted with specimens that can cope with sitting in water for a day or so as well as being able to tolerate periods of dryness, thus becoming more of a garden feature; usually with a swale, the berm is the part that is planted. As with a swale, the rainwater from a rain garden gradually percolates into the surrounding soil. There are many online resources for how to build a swale or a rain garden if you are intrigued by these ideas. It is worthwhile checking if there are any local council restrictions before you start digging!

I'd love to hear other ideas for helping us to prepare for this approaching summer.