Gardening in the heat

You might have noticed that Summers here in Australia are getting warmer. Actually, that’s a bit of an understatement, the kind of humour that Aussies are known for. In fact, its getting very hot, earlier and probably for longer.

Over a relatively short space of time, we are going to have to reassess how we garden, if we’re not doing it already.

One of the facts of climate heating and its associated political mismanagement and corporate profiteering will be that there is, simply, less water to garden with. With less water and increased temperatures, we will have to take a close look at how we garden, what we grow and what we expect.

Our Cooling with our garden page has more tips on gardening for climate control around the house and garden, It focuses on Summer because that’s when we have the most issues and have to put in the most effort.

The Water Saving Approaches to Gardening page covers different systems of gardening that are known for their water efficiency.

If you want a bit more info on keeping your whole house place cool, check out our Summer page. Because mulch is such a vital part of getting our gardens through Summer, we’ve given the subject a whole page of its own here.

Every millimetre that falls on a square metre of your block gives 1 litre of water.

Make the most of the rain

In the past, even in tougher times, we’ve always looked to the skies to help us out, One of the interesting possibilities is that, while there will be less rain around here, it will come in larger downpours – less water, but all at once.

You’ve probably noticed how plants do much better with a little rain – far better than when they’re watered by tap water alone. The best way to utilize a little rain water is to water just before or just after rain. This allows either your water or the rain water to soak in a little better and maximizes the benefits of a bit of rain.

We will have to design our gardens and water catchment techniques to make the most of when the rain comes and extend that benefit throughout the year.

The obvious place to start is with more rain tanks, or at least bigger ones. This isn’t an option for some folks because of money or space. Tanks can be quite large after all. Even if you have the space and cash for more storage space, some of the following ideas may make that investment even more effective. If you don’t have the money or space, the following techniques can help a lot if you want to continue gardening and growing your own food.

Working out how much rain falls on your block is easy. If you can catch it all, perfectly, every millimetre that falls on a square metre of your block gives 1 litre of water.

For example, Ligaya Garden is a 360 square metre block. Our average annual rainfall is 440 mm. That means that we could, theoretically see 360 x 440 = 158,400 litres of rain hit our block over an average year.

You can work out how much rain a particular event has left on your own block in the same way.

Suppose we get 3 mm of rain. That’s 360 square metres x 3 mm = 1080 litres of rain from that down pour that hits Ligaya Garden.

To work out how much you could capture, you just need to know the size of your roof in square metres and multiply that by the rainfall.

I say ‘could’ because we’re just calculating how much rain falls on a your block or roof. There are lots of variables to include for how much you can capture.

Some things that affect the amount of rain you can capture:

  • the size of your tanks
  • how full your tanks were before the rain
  • whether your gutters are clogged or full of debris
  • the size of your gutters
  • if the rain falls slowly or in a massive downpour
  • The temperature of the roof when the rain hits it

One of the things I used to hate was seeing storm water wasted when we had a good rain and one tank was full and another empty. The overflow from the full tank ran away (at least when the tanks were on opposing sides of the house) without filling the empty tank.

I resolved this by having sump pumps in each tank and pump water from a fuller tank to an emptier one before a rain event. This is also how we keep two of the tanks in the front yard full. They’re not connected to downpipes and we pump water from the tanks in the back to them as required.

I mentioned whether the rain came all at once, in one big deluge or slowly over time because too much rain at once can, in the worst case, overflow your gutters and lose water before it reaches your downpipes.

If you’re thinking about installing or upgrading water storage, the Alternative Technology Association has a fantastic tool to calculatecthevsize you will need. It’s called ‘Tankulator‘.

Some of the techniques covered below will help you to make the most of whatever rain may fall.

Rain is gold. It feeds our plants and saves wear and tear on our wallets


Surprisingly, some shade themselves but forget to shade their plants. Any kind of temporary shade or covering can help whether it be a full sized shade sail, garden umbrella, draped shade cloth, old sheets or even cardboard.

Using shade is a balancing act. Too much and your plants won’t thrive, they’ll grow leggy and weak. Too little and they’ll burn around the edges or maybe even die. Shade can reduce evaporation greatly too.

Shade umbrellas help a lot
An old market umbrella shades a few square metres of plants

At the beginning of Summer 2019/2020, we cemented a couple of posts that hold big market umbrellas in the garden at key points. The posts are fixed so that we don’t lose the umbrellas in very strong winds or so that they don’t go walkabout with someone else like one did last year. They also double as the stands for our compost tea makers.

You don’t need to go as big as market umbrellas. We have a friend who has used kid’s beach umbrellas for years with great success. We wanted a bit more permanence. They also give us a little covered space to work in when it’s raining.

Choose the right plants

Sorry to say it but some of your favourites might not make it without lashings of extra water and care. You might have to grow less of them or choose another best friend. I’ve created another page on which I am listing ‘plants for over heated gardens‘ to help with choices. Of course, I’m only worried about useful plants – food and medicine and the like.

It’s interesting that a lot of old school plants will be in vogue again – Geraniums, Money Trees, Cacti and other succulents, so check out your Grandparent’s garden to see what’s doing well there.

I’ve a feeling that Citruses will do well, as will Figs. More sub-tropicals and tropicals will start to make themselves known, if they aren’t already. Of course, Native Australian plants will become very very popular as will hardy, Sun loving weeds such as Purslane. Check out some of the plants on our Bushfoods & Bush Medicines page to get some ideas about what to plant.

Watering tips

Your watering techniques may have to change. Overhead watering and sprinklers may actually be banned in some areas and seasons. Flood irrigation (that’s what I call it when I forget to turn the hose off) could be another taboo.

There are some very effective and efficient ways to water your garden that include:

  • Start watering deeply in mid Spring. This will make sure that the subsoil and the soil under the mulch holds a good amount of water. It’s easier to top it up later than it is to rehydrate the lot in mid-Summer.
  • Water in the morning before 10 am. Too much water in the evenings can lead to mold on some plants.
  • Avoid overhead watering – it can damage leaves and waste water
  • Don’t water when the temp is above 30°C or when it is very windy – water can evaporate very easily
  • Check the temperature of the water in your hose before watering – it can be very hot and damage leaves
  • Water immediately before and after any rain – this helps the rain or water to soak deeper
  • Water pots daily in extreme heat. Place a saucer below the pot and mulch the plant too.
  • Black pots can really cook and dry out the potting mix in them. Paint them white or have some kind of barrier between the pot and the Sun.
  • Water on the drip line of the plant. That’s where the roots are most active.
  • Avoid the temptation to flood the garden in one hit – water areas slower for longer to allow it to soak in
  • Give your plants a little overhead spray from time to time (out of direct Sun, of course). This helps keep humidity up and deters Spider Mites who thrive in dry conditions.

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