Gardening in extreme conditions

The temperature in our State hit record highs in the lead up to Christmas. Across the country, bushfires have been raging, some of them for several months. While I personally like hot weather, and manage the hot weather well (acknowledging that I have the privilege of working indoors and have a roof over my head), of course all gardens and wildlife across the State struggled. A State of Emergency has been declared in one state, while as I write this, we are waiting for a severe storm here after several days of plus-40 degree temperatures and high humidity.

I thought it would be worth writing about how those of us that love to garden manage to do so in regions where the weather or terrain can be extreme.

The climate in our region is sometimes described as ‘mediterranean’ but it would be more accurate to describe it as ‘arid.’ The arrival of Europeans and other non-Aboriginal people to this region after colonisation has forced a different approach to land management, most of it not suited to the very dry conditions. While this year has been drier and hotter than usual, in most years we have a relatively dry Winter, with the highest average rainfall 71 mm in June. This year the rainfall was lower, with only 54.6mm falling in June.

Our Summers are extremely hot, with an average temperature of 29 degrees centigrade and very little rainfall. In late January, we can generally expect at least a week of temperatures in the high 30s or low 40s. In the past couple of years, this has changed. We had a week of mid-40s temperatures in December, and are experienced another late last year. It is likely that the rest of Summer will give us some periods of temperatures in the high 40s (it already has).

Our warm Springs and warm Autumn periods make our region perfect for growing a wide array of Summer vegetables and fruits, particularly tomatoes, zucchini, chillies, and eggplant. However, for the home gardener, the extreme Summer conditions and low rainfall can present some unique challenges.

Some gardeners I know are giving up altogether in regions with strict water restrictions and very low rainfall. In our region we have water restrictions, but they are not as strict: we can water with sprinklers before 10am and after 5pm. In many parts of Australia, there are level 2 water restrictions in place, allowing only use of a bucket or watering can at those times, or drip irrigation for 15 minutes. In weather of 40 degrees plus, this will not be enough to keep most vegetable gardens going.

Drought tolerant gardening

When we moved in here, the previous owners had tried to address the water issue by planting a mix of succulents (agaves and aloes), along with some ground covers and trees. Unfortunately, the trees they had planted were inappropriate for the block and the succulents they had planted, while drought tolerant, were planted too close to other plantings. Everything was crowded in together.

We removed everything and started again. We wanted a productive garden and a sensory garden, where everything could either be eaten or enjoyed by our children and niece and nephews as a sensory experience. We also wanted plantings that could act as a natural mulch or ground cover to protect the soil from the heat, and that did not require too much water once established.

Herbs are a great choice. Even some varieties of mint, which people think requires a lot of water, is drought tolerant once established. We have found spearmint and apple mint to be the most drought tolerant. We planted the following herbs and have found they require almost no water once established:

  • Greek oregano
  • Common thyme
  • Lemon thyme
  • Golden creeping thyme
  • Sage
  • Pineapple sage
  • Spearmint
  • Apple mint
  • Lemon balm (Melissa)
  • Garlic chives
  • Parsley (Curly and Continental)
  • Lavender (English, Italian, French)
  • Rosemary

These plants have self-seeded around the garden and created swathes of living mulch, protecting the soil from the baking sun. We rarely water these; they are watered by the rain and pick up some incidental water when we water the fruit trees and roses.

Roses are also quite drought tolerant. We have three climbing roses. One is admittedly struggling, but it is picking up. The others, planted at the same time, are happy and healthy and are watered about once a month in the Summer, and not at all the rest of the year. They seem quite happy.

Our front yard faces west and is on a hillside, which means that it receives full sun in the afternoon and evening. In Summer, this is very hot and bakes the garden. We have planted deciduous fruit trees that provide shade for the rest of the garden, and mulch the areas that are not ‘self-mulched’ by the ground cover herbs. The trees are now well-established and we water these about once a week in Summer and Autumn until the rains begin (this period is stretching out longer and longer, unfortunately). In Winter and Spring we don’t water the trees unless it is particularly dry. We have a mulberry, apricot, pomegranate, lemon, and passionfruit vine in the front.

Pomegranate

Vegetables

Last year, we lost most of the vegetables to extreme heat, and gave up until Autumn. This is because I was busy with work until late December and did not plant until late. The plants were not strong enough to cope with a 47 degree day. This year, I knew I would likely be busy again in November/December (I was), so I established the garden earlier. I hardened off the tomatoes, capsicums, chillies, eggplants and zucchini seedlings in smaller pots outside so they would be tough as nuts before they went into the ground. This meant that they were well-acclimatised to the micro-climate of our garden. We water them, but not daily, so they receive a deep early soak on very hot days instead of daily short waterings. We fed everything with extra compost and pelletised chicken manure, and mulched the heck out of everything.

The vegetable plants sailed through the first lot of 40-plus days in December with no worries – in fact, they put on growth. We had another 40 degree day yesterday, and all the plants look happy.

Summer veggie patch

Water

Our rainwater tank collapsed during a storm and we have not yet replaced it. It was one of those old galvo jobs, with no pump and about a 2 litre capacity. I think it knew it was useless and collapsed from the shame. It is on our list of things to replace this year, before Winter. As such, we are on mains water only to keep our garden alive. This makes gardening pretty expensive, so for environmental and cost reasons we have to consider our water usage carefully.

I think about the plants I choose to grow. If we had to give up some part of the garden to save the rest due to extreme drought conditions, it would be the vegetable garden, as much as it breaks my heart to say it. Vegetable gardening is the most fun but it is also the most water-dependent. Certain vegetables require more water, so they are not worth growing when water is expensive and scarce. If we had Level 2 water restrictions, I would not grow vegetables at all, except a few in pots, like chillies.

We water only during the water restriction times. We get up early to water or water late after the heat has reduced, to prevent evaporation, and we set a timer. We don’t water the ‘lawn’ (such as it is) ever. We don’t water everyday except in extreme heat. We mulch the soil with compost and sugarcane or pea straw to prevent water loss. We also mulch our pots.

Mulch

You cannot garden in Australia, particularly the arid areas, without mulching. Mulching prevents evaporation and soil erosion. Mulching is both an environmental and economic choice – it reduces the amount of water used in the garden, and saves your precious soil from blowing away.

I use a combination of homemade compost, well-rotted sheep manure, coir, and sugarcane to mulch the garden. I use sheep manure around the fruit trees, applied in a thick layer in Winter. Coir is used on pots and raised beds. The rest of the garden receives a mix of compost and sugarcane mulch. This is a continual process, as the mulch breaks down over time. Other people prefer pea or lucerne straw to sugarcane, but I like the loose texture of sugarcane, and the fact that it is utilising a waste product from sugarcane production. Some people use bark chips as a loose mulch, but our pest control specialist has told us that this could encourage termites, which is the last thing I need around my place (I don’t know if this is true or not, but I am not taking chances on that).

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