Lesson 1 - Plant types and the basics of growing
Planning a space or garden to grow food can be daunting but understanding how plants grow and translating that understanding to your own patch or space is a great way to start.
Like humans, there are many different types of plants. Like us, plants all have different requirements. Some are hungry feeders, some prefer dry feet, some love the sun, some prefer the shade. When planning your first food garden consider that plants are all different in terms of their lifecycle traits and longevity, their growth habit and form, and most obviously their dimensions (height and spread).
Annual plants are those that complete their entire lifecycle in a season or a year. This can be incredibly short for some (just a matter of a few weeks in the case of ephemerals) or two seasons for plants like tomatoes, which start in early spring and finish at the end of summer. In a food garden, most vegetables are annuals.
Perennial plants are those that live for many years. Some examples that you might know are shrubs and trees. In a food garden an example of a woody perennial plant is the herb rosemary (Salvia rosmarinus). Perennials can also be herbaceous (soft-stemmed plants that have a dormant season every year, when they die back above the ground), like sage (Salvia officinalis). Examples of perennial trees in the food garden are the types you would find in an orchard; apple trees, lemon trees and apricot trees.
Diggers tip
Annuals live for one growing season in your climate, spring to autumn for example. You plant them every year, 'annually'.
Perennials live for many years. They live continuously; they are 'perennial' favourites.
All plants need light to survive, but plants vary in terms of their light requirements – some need lots of light while others need very little. Light can be variable, changing according to the time of day, season or year, and the location that plants are growing, particularly the orientation or aspect (the direction your garden faces for example: north, south, east or west) and the effects of any shading and shadowing. Ideally, your garden would face north. Most food plants need good sunny conditions with at least six hours of direct sunlight a day.
Diggers tip
Observe your growing space throughout the day and take into consideration changes in light intensity as the seasons change. If you are growing on a balcony or terrace with a glass window or wind break between your food garden and the elements, consider how much hotter it might become behind the glass.
Plant growth is tightly linked to temperature as it regulates much of a plant’s lifecycle from germination to fruiting.
And like light, temperature is affected by a growing site’s location, particularly topography (the arrangement of natural and artificial features of an area). For example, are you in the shadow of a hill or building? Are you making a food garden near a brick wall, which will retain heat after the sun has set? Are you located on a high level in an apartment building where the wind will affect temperature? Is your food garden on the side of a windy hill or do you live in a valley where cold air is trapped in winter?
Temperature is also affected by aspect, the direction your garden faces, for example the intense heat of westerly afternoon sun will impact on the type of food you can grow. It can be useful to avoid locations that are too hot over summer or too cold over winter, as these extremes influence the range and types of food plants that can be grown successfully.
And it's not just air temperature that’s important - soil temperatures also affect plant growth outcomes. Tomatoes, for example, typically need soil temperatures of at least 16 degrees Celsius to grow successfully.
Diggers tip
The 'gardener's soil bum test' is a good way to test the warmth of your soil. Sow warm weather annuals (plants that live for one growing season) when you can sit on the soil with your bare bottom comfortably. Just keep an eye out for the neighbours!
Having access to water is critical to successful food growing so ensuring there is a supply of water available before starting a food garden is vital.
However, plants vary in terms of their water needs. Annual vegetables tend to have higher water needs than longer-lived perennial crops, although amongst the annuals there are some, such as corn, that have particularly high-water needs.
In some locations there will be too much water, particularly in heavier soils or in low-lying locations, so drainage becomes important.
Diggers tip
If you are planning a balcony garden, consider the location of your nearest tap and what happens to any water run-off - you don't want to flood the floors below! If you are planning a big food garden, make sure you can get water down all those rows of yummy vegetables and berries, and to the base of all your fruit trees.
Most plants take in carbon dioxide and then release oxygen as a by-product during photosynthesis (a process that uses light energy to produce chemical energy for plants to grow).
But air movement is a factor in many growing situations. Windy sites can lead to plant damage from too much wind while still and dank locations where there is little air movement can be great places for plant diseases to grow. Low-lying food garden sites may be impacted by frosts as cold air pools in the lowest parts of our topography.
Diggers tip
Sit in your food garden site and determine which direction the prevailing wind comes from. In broad terms Australia is dominated by westerlies in the southern states and easterlies in the northern states.
Soil provides support for plants to grow but also holds water and, importantly, stores and releases nutrients for plant roots. Soil is the key to growing the best food garden possible. Soil types vary in their physical properties and also depth, and there are three main soil types - clay, sand and loam. These soil types vary in their ability to hold and store water and nutrients, and also to drain.
Clay holds water and nutrients but can be very hard for plant roots to penetrate and is prone to cracking when it dries out. They are known as fine textured or heavy soils as they are dense in structure. Sand is made of larger particles and doesn't hold as much water and nutrients. Plants can easily take root but find it hard to obtain water and nutrients as they tend to leach through the soil. You will find that you need to water more if you have sandy soils. Loam is the ideal kind of soil. It is an even mix of sand, silt and clay and is high in organic matter. It holds the water and nutrients that are needed for food growing.
Plants can grow well in ‘non-soil’ locations, such as containers, and by using methods of growing like hydroponics – but to grow plants successfully, support, water and nutrients still need to be provided.
Diggers tip
Some final considerations. just like us, plants are different - suited to different climates, variations in nutrient inputs and amounts of water. When growing food, we need to keep this in mind as it impacts on how you care for your garden.
Further learning
Further Learning
- Positioning a productive garden - Gardening Australia
- Site analysis - Gardening Australia
- Important steps to take before starting a garden - Gardening Australia
- Sprinter and Sprummer: Australia's changing seasons by Tim Entwisle (CSIRO Publishing, 2014)