When asking new gardeners what question they most want answered about gardening, a common answer is, "how can I keep my plants looking healthy?"
Good question!
The simple answer is to determine, and then meet our plants cultural requirements, but what does this mean?
All plants have preferred conditions to live and grow in. Plants are actually really good at living and growing, and if we put them in an environment where these conditional requirements are being met, the plants are more than capable of taking care of the rest.
Apologies for the sass, but if your lack of confidence or 'black thumb mentality' in the garden is holding you back, you needed to hear it. People often stress themselves thinking they have to have some kind of skill to grow plants, when in actual fact it just comes down to researching and then meeting their cultural requirements. The actual living and growing part is handled by the plants - it's hardcoded into their DNA, it's what they do. Quit being intimidated by plants.
We live in the age of Google, so it is easier than ever to research the cultural requirements of new plants we are buying. One hundred and fifty years ago explorers and botanists had to go to a lot of effort and trial & error to determine the best ways to cultivate what are now our favourite plants, but nowadays if your plants are being sold commercially, someone else has already figured out their cultural requirements, and the hard work has already been done for us.
So what are the cultural requirements of your plants you may wonder? Below we've listed six different cultural conditions we need to consider when growing new plants. Remember, different plants have different needs, for example plant a may need more water and more sunlight than plant b, but we still must consider each of these conditions for each of our plants before buying and planting.
CONDITION 1: CLIMATE
When we talk about climatic cultural requirements for our plants, we're talking about temperature, humidity, rainfall, and wind patterns throughout the year. While at first glance we can realise the need to choose plants that can handle the extremes of our climate (a 'tender' tropical plant that cannot handle temperatures below 5'C will be at risk in Melbourne's Winters), we also need to consider other factors.
Frosts, strong winds, heavy rains, extreme droughts, average humidity levels throughout the growing season, all effect in-ground, outdoor plants, while we also need to understand the optimal growing season conditions that our plants will have too. For example, it isn't difficult to keep a banana plant alive in Melbourne, but getting a banana to flower, fruit, and then for the fruit to ripen can all be quite difficult with our relatively short optimal growing conditions for banana plants.
Furthermore, consider the differences between growing pot plants versus indoor plants. Pot plant soil temps will warm up quicker than inground plants, but they will also dry out and need watering quicker, and require more frequent fertilisation. Even so, pots can be moved under cover or even indoors during inclement weather, so make it possible to grow plants otherwise unsuited to our climate.
Finally, when growing pot plants as indoor plants, consider the year round temperature and humidity of your home. Temperatures are likely to remain between 15'C and 25'C in most climate controlled homes, which is ideal for many tropical plants, but we'll need to consider the humidity of the home matches the humidity requirements of the plants, and also remember that the lack of periods of freezing combined with altered day/night length hours will interfere with some plants ability to produce flower and fruit buds.
CONDITION 2: SUNLIGHT
Plants require sunlight to perform photosynthesis, but different plants in different conditions require different levels of light. Usually, outdoor plants will tell you on their labels what sunlight requirements our plants will have.
Outdoor plants will usually require 'full sun' (6-10 hours of direct sunlight or more), 'part shade/part sun' (3-6 hours per day), 'shade' (indirect or dappled sunlight, protection from direct sunlight), and 'heavy/deep shade (low light levels).' Indoor plant labels often use different terminology, referring to 'sunny spots' (more direct light), and 'bright, indirect light' (out of direct sunlight, but in a brightly lit location out of actual darkness). Despite the differing terminology, the principle remains. Follow the advice of your plants label, ensure your plants needs are met, and it will reward you with healthy growth.
Also consider how the changing seasons bring about changing light conditions in the garden. Shorter days and the lower angle of the sun will reduce available sunlight in many scenarios during Winter, while buildings and tall trees will also be more likely to cast shade due to the lower sun angle. Consider also the changing conditions beneath deciduous trees, which lose their leaves heading into Winter, and leaf out again heading into Summer. Take this into consideration, and even use it to your advantage, and you will do well.
CONDITION 3: SOIL
Soil is probably the most important factor that we can control when growing outdoors. Poor soil will equal poor plant health. Consistent with the theme that different plants have different cultural conditions, different plants will have different soil preferences.
Some plants prefer heavier, boggier soils, while others prefer lighter, freer draining soils. Some soils call for high levels of organic matter, which can be achieved by digging compost into the mix, while others call for both moist AND free draining soil at the same time which, despite sounding like an oxymoron, just means a well structured, loamy soil with a good mix of clay and sand, with a healthy amount of organic matter mixed in.
The ideal soil for most (but not all plants) will be a loamy mix of sand, silt, and clay, with a good amount of organic matter. These soils will retain moisture and fertility well due to their organic matter and clay content, but the organic matter and sand will form larger aggregates with the clay particles which allow for better aeration and drainage as well, giving us the best of both worlds. Remember to always read the plant labels and give your plants what they need, and you will be rewarded.
CONDITION 4: WATER
We know plants need water to grow and function, but the number one cause of pot plant death is overwatering. Obviously, how we go about watering our plants is a bit of a mystery to some, but it doesn't have to be. The two most common questions are, "how much water do I give my plants?" and, "how often should I water my plants?"
To answer the former, we want to give our plants a nice and deep water to encourage their roots to shoot down deep. As for how much water we need to do this, it depends on both your soil drainage and the root system of the particular plant you are watering. When watering pot plants it is usually sufficient to just water until the point where water will drain from the base of the pot, but for inground plants the process is more complicated. Carrying out drainage tests can help when estimating how long to run your irrigation system for, and observing your plants responses to irrigation will also provide feedback, and for those with the time, doing some further reading into irrigation management and learning about field capacities, permanent wilting points, and management allowable depletion levels will be of great value.
To answer the latter question, we should water our plants only when they need it. Often times plant labels will tell us to, "maintain moisture at all times," or to, "allow the top 2cm of soil to dry out before watering again," and we should make every effort to follow these instructions for the good of our plants. If labels aren't present, the ideal time to water our plants is just before water stress occurs, and seeing as we can't be aware of this point in time without moisture sensors and prior knowledge, the next best time is as soon as early symptoms of water stress (such as discolouration, loss of vigour, minor leaf cupping and wilting) appear. Failure to water in time will lead to more permanent wilting and cell death, and though plants can often be brought back from the brink of death, once leaf cells begin to die and go crispy, that tissue will not recover.
CONDITION 5: NUTRITION
Like humans, plants need nutrients to survive and thrive. Plants obviously need different nutrients, but they need them nonetheless. Plant nutrition is a complex field that is constantly evolving, but in all honesty if we read our plant and fertiliser labels we will be on the right track.
Some plant labels will recommend feeding every few weeks or months during the growing season, while others will recommend feeding every few weeks or months year round, and then will recommend a type of fertiliser to use. Disregard the frequency recommendation (we will determine frequency based off of the label on the fertiliser we purchase, as different formulas last for varying periods of time), but take note of the type of fertiliser used, and whether we should be fertilising year round, or just during the growing season.
The next step is to read the fertiliser label to find out how much to give our plants, and how frequently. Granular fertilisers will last longer than liquid fertilisers, but with slower acting results, while liquid feeds can produce quicker results but with a higher risk of harming plants if we get the measurements wrong.
While plant nutrition, diagnosing nutrient deficiencies, and maintaining healthy soil fertility are complex topics all worth looking into for serious gardeners, by following the care labels of our plants and fertiliser products even the newest and most disinterested gardeners can safely keep their plants well fed.
CONDITION 6: MAINTENANCE
The last cultural consideration essential for healthy plant performance is their maintenance. This includes their pruning and cleaning. Like each other field mentioned here, plant labels should instruct us when and how to prune, when to lift and divide if necessary, and any other maintenance tasks.
Commonly plant labels will call for the removal of dead and otherwise nasty leaves, as well as spent flowerheads to encourage ongoing blooms. More extensive annual pruning to encourage blooms and keep plants young and vigorous will usually be outlined in simple terms too, and while less common with modern landscaping plants, when to lift, divide, or store plants such as daffodils and tulips should also be outlined on the plant label. Be aware that some plants that die back each year should have their dying leaves left on the plant so that their energy can be stored in the plant roots/bulb, but this instruction will almost always be included on the label as well.
CONCLUSION:
In all honesty, this post can pretty much be summed up with the single instruction to read the care label the plant came with. An in-depth understanding of horticulture will certainly make a world of difference when attempting to manage large and complicated gardens, as well as taking gardens to that elusive, elite level of quality, but in all honesty anyone who can read and comprehend a plant label can have success in the garden.
Remember, plants are really good at living and growing. It's pretty much all they do, and always have been doing. It's in their DNA! Our job is to stop stressing about having black/red thumbs, focusing instead on identifying the cultural requirements of our plants and then giving them what they need. The plants will take care of the rest.