Garden Preparation for Extreme Temperatures & Conditions

    Australia is a country of extremes, and no capital city is much more extreme the only inland capital, Canberra. While the summer may only last a couple of months, and winter seems to run closer to 5 months of the year, the temperature range goes from -8oC all the way to 42oC! Gardens, like animals tend to struggle in the extremes, so here's some helpful advice.

    Prevention really is better than cure:

    Choose appropriate plants to begin with, and put them in appropriate places.

    The number of times I have seen plants put in utterly stupid places. Don't get me started! I should say that it's the norm, not the exception because most people don't think about the difference a different aspect, location, or soil type may make. The micro-climate in a small courtyard can be significantly different from one side to another. Ok so you like blueberries, which need lots of sun, a somewhat acidic soil, good drainage, and regular watering. Don't stick it in a shady spot, with poor drainage, alkaline soil, and intermittent watering.

    Similarly, a west-facing wall will always be hotter during summer than an east, even if it gets the same amount of sunlight each day. Westerly wall locations are hotter as they get the direct sunlight when the day (and the surrounding air) has already heated up. So heat-tolerant plants are needed on west walls.

    Choose your best planting time with thought... not assumption.

    It may seem counter intuitive, but in Canberra, it is actually better to plant in autumn, (with conditions) than the spring/summer period, as the hotter months are actually more stressful for plants. If you plant in autumn, have decent soil, and don't fertilize it much at all during planting, (that only encourages lots of new foliage, which may not be frost hardy) the plant will have a month or three to acclimatize, then happily hibernate through winter (some species may need frost protection) and with a little luck the plant will have established some basic roots before the chill happened, and be ready for a solid spring of growth.

    Contrast that with spring and summer planting. If you are anything like me, you may not really get as much spring as you'd like. Late frosts and cold Septembers are normal in a lot of places. If you live somewhere like Canberra, you have usually lost a lot of spring by the time the frosts have subsided and you finally get your plants into the ground. They're stressed already from the move, and the roots haven't established. Then a blistering summer comes, you go away for that well-earned break, and come home to a stick formerly known as your plant. Irrigation system present or not.

    Watering to a schedule, don't spoil your plants.

    It's often tempting to give your plants a "big drink" when it gets hot. However, if you water too often, you can not only rot your roots, you may actually drown your plants. Also, by subjecting your trees to cycle between a good soak, then allow the soil to dry-out a bit, (maybe drying will take a day in summer, or up to a week in winter) cycle, you harden the plant to droughts and deluges alike. Many gardeners water by hand, and often "guesstimation" about how much water to give a plant based on it's condition. However, it usually requires the plant to show signs of stress before the well-meaning gardener knows to make an adjustment. Obviously, that's not ideal.

    Irrigation systems are a big help here. They not only keep things watered when you're away, they allow you to stick to a much more accurate schedule and consistent dosing strategy. However, this assumes you have consistent water pressure and flow rates. If you're constantly turning the tap on and off to your irrigation system, or your pump is a bit erratic, this can lead to significant variances in watering. It's recommended that you ensure taps are allowing enough flow for your irrigation system, making a note of how many turns your tap is on to get to that point, and generally leaving it alone once you're happy.  Then you can leave the rest to your controller to measure the water by specifying the duration of watering, the frequency of watering, or on more advanced models, what zone is irrigated at any particular time.

    The cheapest controllers, are basically a valve you connect to your tap, controlled by a timer. More advanced ones include multiple programs, where they may have two, three, or anything up to 16 zones. Being a crazy tech head, I opted for a controller that uses a Wi-Fi based Internet connection to check the weather forecast, minimum and maximum temperatures, humidity, predicted rainfall, soil type, plant type, slope gradient, and expected evaporation rates to follow the schedule, water more when it's dry, or completely bypass watering altogether when it's not needed. It saves a ton of water, and ensures plants are given enough water. You can check out the manufacturer's site for the one I have at:

    Note: If you decide to get one, you need to have an Internet connected Wi-Fi access point, router, or modem. For whatever reason, Rainmachine controllers can only use 2.4GHz WiFi frequencies, and after much frustration, I found that they don't like using certain Wi-Fi channels, depending on which country you're in. I have the basic 8 zone "mini" model, and in Australia, if my Wi-Fi access point is using channels 12 or 13 for communication, it won't work, and you need to configure either the device, or the Wi-Fi router/modem/access point to use another channel. For more information, see:

    Irrigation is a topic that whole books could be dedicated to. I'm not going to write a bunch here. However, I will recommend the following advice:

    • Water the ground, not the plants. (Watering leaves can encourage diseases on foliage such as moulds, fungi, and powdery mildew, and spoils certain varieties of fruit). Spray heads are a prime cause of these, and lose a lot of water in evaporation.
    • For water efficiency, use drippers wherever possible. These units can come in set flow rates, or variable. I use the variable kind so I can put more water where it's needed, and less water where it's not. It's even possible to turn them off if your plants have died of in the winter, or they've been moved elsewhere.
    • Weeping hoses are a finicky option to use. (Weeping hoses have tiny porous holes that are designed to leak under pressure). Weeping lines are only useful when you have enough pressure to open the pores. Otherwise, the flow rate is minimal, and they need very long watering times... if they work at all.
    • Sprays are really only suited for seedlings and cooling small children (at least in my opinion).
    • If you don't have enough pressure to water everything, split the irrigation areas up into zones. Then each can be programmed sequentially to run at different times, and even durations. This is very handy if you have everything from seedlings to fruit trees.
    • Check your irrigation system regularly. Like anything, they break, clog, burst, leak, or just stop working for a variety of reasons. During winter, it's not unusual for frost to freeze the water in the lines and block them. Set your watering to a warmer part of the day like the afternoon to ensure water is being delivered as expected. If any plants look like they're not doing well, check to see if water is coming through there, and adjust upwards, then if no improvement happens, try turning it down. Alternatively, stick your finger into the soil, and if it's moist, it's unlikely that the water is insufficient, so you can check for other issues such as being root bound, diseases, or maybe it's just an old plant.

    Extreme temperature preparation:

    Mulch, mulch lots, mulch often.

    Mulching is a fantastic way to help alleviate the strain on your plants. It helps to retain soil moisture, it breaks down and provides nutrients to your plants longer-term, and stops the sun from directly hitting the soil, moderating the soil temperature.  This is perhaps the simplest thing you can do. Whether you buy straw, pea, or cane mulch from the shop, sweep leaves (preferably shredded) or even pour spent coffee beans around your plants, you're helping something. (Although coffee beans aren't the best mulch, and are far better used in a worm farm, or compost bin first). I generally aim for a mulch depth of 2-5cm of a lighter mulch (small leaves, or pea straw) when planting seedlings, and around larger plants, I aim for 10cm thick of mulch using similar light materials, and mixing in even heavier mulch ingredients like straw/hay bales, leaves, some types of wood chips, even shredded remnants of pruned branches. Remember: Clear a little room around the stems/trunks of bushes and trees, otherwise you may encourage disease.

    What is "Living mulch" or "Green mulch?"

    Ground covering plants like thyme, strawberries, and comfrey when grown in a mat become a "living mulch". By shading the ground, the still-living leaves cool the soil and increases water retention, the leaves also create a habitat for many beneficial bugs. Ground cover plants reduce erosion while simultaneously allowing airbourne dust, leaves, and other matter to become trapped so they don't blow away, this is a natural form of mulching, and soil building for that matter.

    Living mulch, like all things, can be both a blessing and a curse to your existing, larger plants, which leads me to...

    Companion planting, guild planting, and creating microclimates.

    Most people don't realise the effect plants can have on each other and the immediate environment. By planting lots of plants, you're encouraging competition, but also increase evapotranspiration (evaporation through leaves) which cools the immediate vicinity, and increased plant coverage shades the soil from direct sunlight. This basically helps to cool the area and maintain soil moisture during hotter months.

    Certain plants actually work well, even symbiotically together, while others do not. Famous companion planting combinations like Tomato and Basil, (don't just work well together in pasta and pizza) but also help each other grow, deter pests, and attract beneficial bugs for pollination and pest control. Companion planting is a great thing to do in a garden, but why stop at two plant species? What happens if we go to three? Another famous combination is called "The Three Sisters", used by native Americans, they grew corn, beans, and squash together. The corn grows tall, and have deep roots to anchor everything to the earth. Corn, being so tall, provides a natural trellis for the beans to grow up. The beans take nitrogen from the atmosphere and put it into the soil for all three plants to benefit (saves on manure). By weaving through the squash and the corn, the beans also tie it all together to protect the crop from wind and storm damage. Finally, the squash leaves had spines on it to stop raccoons from eating the crops, and by shading the ground with the big leaves, created a "living mulch" for all three plants to benefit from. All three combined to form a healthy (and important) part of the native American diet, while using nature to address reduce the work involved.

    Of course, there are combinations of plants which do not go well. Usually these either compete for the same nutrients, they deplete the soil of many nutrients, or attract bugs that eat other plant species. Some plants are "allelopathic", which means they suppress other plants growing nearby by releasing certain chemicals into the surrounding soil. One example is the Black Walnut, another, the Elderberry.

    Once you start getting into groups of symbiotic plants, planted together, you get a "guild". However, it's not just about what species work together, but also, how best to arrange the plants within the guild so you can minimise problems. For example, if you're in Australia, with the sun coming in from the north, it doesn't make sense to put the tall trees where they'd shade the shorter sun-loving plants. Similarly, putting all your cherry trees together encourages pests to spread to all of your trees very easily. By putting in other species of plants between your cherry trees, you might get only one tree affected because bugs have to work harder to find the other trees.

    For example: Our cherry tree has often suffered from "cherry slugs" which eat the leaves until there's little left, then the slugs turn into a type of fly, they mate, lay their eggs on the tree and in the soil below the tree, and then they hatch the next year, crawl up the tree and eat it all over again. So we grew a kiwi fruit vine and ran it up into the tree.. and suddenly by the end of summer, there were still intact leaves on the tree. It seems that the slugs were substantially less able to eat the leaves. They weren't gone, but the improvement was noticeable.

    Microclimates aren't just about the plants, but the materials nearby, the presence of even partially-effective shelter from weather extremes can make a big difference.  The presence of water also has an impact, as the evaporation and thermal load of the water moderates temperatures surrounding them. It doesn't have to be big, it might be a stream, dam, river, pond or fountain. The built environments also have an impact. Bare soil, bricks, concrete paths, metal fences, and even the colours used to paint a house can make a substantial difference in actual (and perceived) temperature of an outdoor area. In Canberra, where frost kills a lot of young citrus, planting lemons along north facing walls keeps the frost at bay enough to grow successful trees, and get impressive yields.

    Consider the garden space as it changes throughout the year make a plan not just for now, but for the next 12 months:

    I, like lots of gardeners grow a lot of annual plants like tomatoes, basil, cucumbers, lettuce, pumpkins, potatoes, and even sweet potatoes, but I also have a lot of permanent plants too. Extreme weather isn't just something you are randomly chosen to be either "caught out" by or "miraculously survive". It takes a plan. Have I always had one... frankly... no... and I've paid the price.

    Naturally, having a well thought out plan includes many details, a small sample of potential plans include:

    • What the known microclimate is likely to be like where you're gardening,
    • what to plant at different times of the year, and whether that's likely to work with your existing area,
    • whether to stagger your carrot planting so you don't have all becoming ready in the same week,
    • noting down where and when you need to prepare your soil as crops mature and get harvested, and
    • when and where will you rotate your crops to avoid diseases and depleted soils from one year to then next.

    However, even more important, is making notes about what what the weather was like, what actions you did, when you did them, and how well it worked, all with notes about what to try next time. So when you extend your existing plan, you know for certain, that you aren't making the same mistakes, and you're taking steps to rectify situations as they occur.

    Knowing what's happening now, and what will happen, what needs to be done next, and why, not only helps you to be a more prepared gardener, it saves time, effort, regret, and most importantly money. It also helps you to avoid the pitfalls, gives you better yields from healthier plants, and makes gardening a whole bunch more manageable. Especially when there's more than one gardener!

    Things to consider in your plan:

    • Don't rush into planting plants, it's better to observe and make notes about your space. You'll know a lot more after 12 months than you do now. Take the time to make informed decisions based on collected climate data, rainfall, soil type, aspect, water, buildings, drainage, and know where utility lines, gas pipes, electrical wires, and communications might be.
    • Have a map. Label all of your garden beds/zones/areas, and include permanent fixtures around it, like trees, walls, fences, and how high they are. Topography is also important.
    • Maintain access to all areas at all times! Don't block walkways, roads, or access to utilities. You need to get access to grow, manage and harvest.. don't be afraid to leave gaps in your garden. One Permaculture farmer I know managed to plant his orchard too close to his driveway, so they built the house when all the trees were little, then when it came time to moving out, the moving truck did NOT have the space to move up the driveway. So plan your plants based on their mature size, rather than what you have now, or even in just a few years.
    • Decide what plants are going where, and what sort of soil is there, is it appropriate?
    • Put stuff you use all the time (like herbs) closer to  your home, things that only need to be harvested once or twice a year, further away.
    • Do you fill in a garden bed with entirely new soil, augment existing soil, or try to mechanically, or chemically change the soil you already have?
    • Water, how much, and how often, how do you get plants with similar needs to be in a single irrigation zone for consistent watering?
    • Sun.. plants like the sun, so it makes sense to know how much different places around your garden get. There are some amazing apps like "sun seeker" for mobile phones which really help you see how it changes over a day, or even during differing seasons. Also, check to see how high and wide each plant will get. Put smaller plants in front of the sun-ward side of taller ones, so many plants get the sun they need.
    • Plant compatibility, what works together and what doesn't.
    • Pest and disease management, deter pests, attract beneficial insects and/or bird life, put plants in the right spot so their health isn't as easily compromised.
    • How much effort are you willing to put into this garden, start small, and work yourself outwards from there.
    • Emergency considerations, particularly for larger and more remote properties:
      • Fire (fire breaks, water for fire fighting, fuel management, choice of building material, etc) Here's a tip, don't use plastic pipe for fire fighting lines.. they melt, and leak uselessly.
      • Flood (where is the flood line?)
      • Extreme weather (build wind breaks, protect animals, home, garage, etc)
      • Mud/land slides (it's amazing what a bunch of deep-rooted trees, interspersed with smaller plants can stabilise on a steep hill, couple that with swales, and runoff management, and you have yourself a serious preventative strategy)
      • Emergency Services and their needs. (gate access, ability to drive trucks to wherever the problem is, clear signposting to home, shed, etc should someone need help there)
      • Medical emergencies (first aid training/kit for cuts, scratches, and the occasional insect bite are expected in gardening. Also consider access to medication and vehicles, especially when undertaking higher risk activities, such as cutting trees down, ladder work for harvesting taller fruit trees, and carrying heavy loads)
      • Communication, reception, and alternatives.
      • Community considerations, how others might influence events on your property, and your actions might impact on theirs, maybe you're starting a new bee hive, or have a shed with lots of machinery next to your neighbours bedroom/office/study/nursery. It pays to talk to them and manage some sort of compromise before issues are raised.
      • Legal and financial issues: Fence lines, wandering pets/live stock, noise, chemical sprays, weeds, water harvesting and use, public liability, theft, malicious damage, etc, etc. Planning can at least reduce the likelihood of legal/financial events occurring.

    Now before you get scared off, by my emergency considerations, I'm just trying to avoid all sorts of extreme events. Obviously, not all of these will be applicable to everyone, but it's worth considering each of them. If you document that you put in some plans to manage a bunch of stuff, and if a problem comes along, insurance companies, or aggrieved parties will have a harder time proving that you a negligent. Again, a plan (documented) with evidence that you implemented those plans with actions and why, can save you from financial/legal issues.

    I hope this helps, stay safe, and helps with your gardening.




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