A highly productive vegetable garden that produces lots of food all year doesn’t just happen, it comes about through intentional design. It’s achieved by selecting appropriate plants and using particular gardening techniques that extend the harvest season.
Gardening Calendars And The Importance Of Timing
A gardening calendar is more than just a reference, it’s a valuable tool to help gardeners get organised, perform scheduled tasks and carry out long-term planning. Good gardening calendars usually contain more than just seedsowing information; the better ones will detail the expected weather patterns of the month and list the garden tasks that need to be performed, making each monthly gardening experience much more structured and predictable.
Growing annual vegetables is probably one of the most time-consuming, labour-intensive and resource-demanding ways to grow food. If you want the rewards, you have to make the effort, there’s no two ways about it. To increase the efficiency of such a laborious practice, gardening calendars were developed to assist with scheduling (by letting gardeners know when to sow seeds) and to help with planning (by indicating how long it takes from planting time to harvest), so the sowing of one crop could follow soon after the harvest of another. It goes without saying that a productive annual vegetable garden is one whose garden calendar is fully booked out year-round.
Annual vegetables live for only a warm or cool season, then produce seed – they’re very much plants in a hurry! Sowing seeds and planting seedlings as early as possible minimises slack time in the garden where nothing is growing, and gives annual vegetables the longest possible growing time, maximising productivity. So, if you want to get in early with annual vegetables and not waste valuable growing time, look up a gardening calendar to find out when you can start planting!
It’s important to be aware that gardening calendars are for seed sowing, and using the current month’s gardening calendars won’t work for seedlings because they’re four to six weeks ahead of seeds. When planting seedlings, it’s best to refer to the previous month’s gardening calendar or even the calendar from two months ago, because that’s when the plants were listed to be sown as seeds.
Using a gardening calendar can provide significant productivity gains for conventional annual vegetable growers, but permaculture has a bit more to offer to gardeners who wish to increase yields.
Succession Planting, Stacking In Time
In permaculture, we seek to emulate natural systems to garden more efficiently. In nature, it’s common to see an old tree surrounded by other trees that have grown from its seeds, all at various stages of development. In such a scenario, when the old tree dies off, it is immediately succeeded by the other trees already growing around it, which take its place. Nature normally doesn’t clear out spaces and then replant from scratch, it employs a system of continuous growth.
One reason gardeners don’t follow their gardening calendars is because their previous season’s vegetables are still growing. They wait until their plants have died down before planting the next season’s crops, mimicking conventional agriculture. This is not what nature does. Using the technique known as succession planting, we don’t wait for the previous season’s crop to finish before planting the next one; we plant the new season’s plants alongside the old, as soon as our gardening calendars say it’s time to do so. That’s why we use gardening calendars!
As the old plants come to the end of their fruiting/productive cycle for the season, the new plants begin their growth cycle, getting a good head start early in the season. In permaculture parlance, we call this ‘stacking plants in time’. This method enables extended cropping throughout the season, without having bare spaces in the garden or ‘slack time’ when nothing is growing. By giving annual vegetables the maximum growing time possible, we give them the opportunity to reach maximum cropping levels, or produce multiple harvests during their productive season.
To illustrate how succession planting works with a practical example, we don’t need to wait for our tomatoes (which can take ages to decline) to finish before planting our cold-season crops, such as broad beans: when it’s time to plant the broad beans, we plant them amongst the tomatoes, and when the tomatoes begin to seriously decline, the broad beans will already have put on significant growth, taking the tomatoes’ place in the garden beds.
Perennial Edibles And The Permaculture Approach
What differentiates conventional agricultural and peasant farming systems from permaculture systems? Other than soil cultivation methods, the way human labour and machinery are used and the use of resources for energy production, the glaring difference between these systems is the use of perennial plants. The former mainly rely on annual plants, while permaculture systems mainly use perennial crops.
Why use perennials rather than annuals? Well, nature is approximately 80% perennials and 20% annuals, which is why it’s so sustainable … permaculture emulates nature for good reason!
When we look at which plants can grow where around the world, climate is normally the main determining factor in food-plant species selection. In cold climates many perennial plants from warmer climates (such as chillies) are grown as warm-season annuals because they don’t survive the cold, but they can be placed in a greenhouse or brought inside to keep them alive over winter.
There are plenty of perennial edibles that can be grown in temperate climates. It is possible to grow them among the trees, berries, herbs and companion plants. Some of these are: arrowroot, asparagus, Chinese wild yam, chives, edible canna, French sorrel, garlic, globe artichoke, Jerusalem artichoke, jicama, Lebanese cress, lovage, manzano hedging chilli, mushroom plant, perennial leeks, perennial nettle, potato, potato onion, red-vein sorrel, rhubarb, rock samphire, rocoto tree chilli, salad burnet, samsung, seven year beans, sweet potato, taro, tree onions, warrigal greens, Welsh bunching onions, wild rocket and yanco.
If perennials are frost-sensitive they can be grown indoors, such as bird’s eye chilli, chenzo chilli, Thai basil and chives, which can all grow happily in the kitchen.
Beyond terrestrial gardening, there’s still the whole world of aquatic gardening, which holds so many possibilities. Aquatic ecosystems are among the most productive ecosystems in the world, comparable to rainforests. Asian cultures utilise so many perennial edible water plants, which grow well in ponds as well as boggy areas.
Perennial aquatics edibles grow well in both water gardens and hydroponic systems – these include water chestnut, water celery, watercress, duck potato (arrowhead or sagittaria) and several taro varieties.
And let’s not forget the native bush foods that the Indigenous people of Australia have cultivated for millennia. Yam daisies are easy to grow if you keep the snails off them!
Try experimenting with perennial edibles from other cultures, learn about them, teach others and share these plants with your local community. That’s the permaculture way – embrace it!
Clockwise from top left: Tomato seedlings raised in the warmth of a greenhouse; New silverbeet coming up as the brassicas come to an end; Rocket flowers; allowing plants to flower and go to seed, allows them to self-sow. Photos by Robyn Rosenfeldt
Extending The Growing Season Through Microclimates
The permaculture design principle of ‘relative location’ is a useful guide for extending the harvest season. We can intentionally choose locations that help replicate the specific seasonal requirements of annuals or climatic requirements of perennials to extend their productivity.
Growing tomato plants (or any other warm-season annual vegetables) close to a thermal mass, such as a north- or west-facing wall, will extend their growing season, as the heat absorbed during the day will radiate out at night, creating a microclimate that is warmer than the ambient temperature of the surrounding air on cold nights. Water tanks also provide a good thermal mass if they’re located in a sunny position.
The best way to keep plants warm when the weather is cold is with a greenhouse. The growing season of warmseason annuals can be extended considerably in an unheated greenhouse, allowing plants to be started earlier in the season and to crop for much longer. Homemade greenhouses work perfectly well – there’s no need to spend big dollars. Tomatoes are a great example – when grown in a greenhouse, they can be planted out a month earlier than usual and then crop for two months longer than when planted outside. This extends the growing season by a whole three months!
Even without a greenhouse, the growing season can be extended simply by starting warm-season vegetable seeds indoors a few weeks earlier to give them a head start, allowing them to produce earlier in the season and for longer. For example, you can start your tomato seeds in August, the last month of winter, by placing the seed trays on top of the fridge. Any other continuously warm domestic appliance works just as well, as the heat gets the seeds growing nicely, after which they have to be moved close to a sunny window to get enough light. Planting into the garden happens after the threat of frosts has passed.
Many different microclimates exist in a garden and they affect plant growth. The only way to discover them is to plant warm-season annuals in different locations around the garden, rather than all in the one garden bed. From my observations, I’ve noticed a pattern: plants in bright, sunny, exposed locations will grow faster and produce earlier, but tend to die down earlier when the cooler temperatures arrive. Conversely, plants in protected locations take a longer time to become productive, but have a longer growing season and sometimes even survive the winter chill, continuing to grow the next year.
With succession planting systems, the new cool-season crop can create a protective microclimate for the older warm-season crop when the cool weather arrives. Tall, leafy, cool-season crops, such as broad beans, shield tomato plants from cold winds and temperature extremes, keeping them alive and cropping longer. If the tomato plants are overgrown and fall over, leaving them close to the ground under the cover of cool-season plants often allows them to survive temperate winters and continue growing in the following spring. Tomatoes and chillies can survive in cooler climates, two years in a row this way.
In nature, self-seeding is an important part of the succession process, and it can work in annual vegetable gardens too. When left to self-seed, many warm-season annuals, such as tomatoes, grow when they feel ready, often well ahead of the planting season, producing stronger plants that are better adapted to the growing location. Natural selection is a wonderful process and volunteer seedlings can take a lot of the hard work out of annual vegetable growing.
The productivity of an annual vegetable garden can be increased by utilising any of these techniques, either singly or in combination. The only way to figure out what works best in your garden is to give it a go and see what happens!
Angelo’s printable monthly gardening calendars for temperate locations are available at www.deepgreenpermaculture.com/gardening-calendar-australian-temperate.