Composting recycles organic waste into a product that makes garden soil healthy. Mature compost is a dark brown, sweet-smelling material that can be added to topsoil.
There are two ways to make compost – aerobic, which requires aeration during the process, and anaerobic, which is a slow, rather smelly process. Mature aerobic compost can be produced in about 6–8 weeks in most areas of Australia.
How does compost make garden soil healthy?
Compost keeps soil more moisture-retentive, yet better-drained.
Compost provides food for earthworms that increase the depth of fertile topsoil by leaving digested food along their deep tunnels.
Compost provides food and a home for the many helpful bacteria and fungi that help protect soil from soil-borne diseases.
Well made compost has a pH of 6.5 – where all plant nutrients are fully available, and the perfect pH for the majority of plants.
Compost buffers plant roots from an unsuitable pH in surrounding soil.
It also insulates plant roots from temperature extremes so that soil stays cooler in summer and warmer in winter.
Compost contains all the minerals that plants, animals and humans need for good health, most of the soil’s nitrogen, plus lots of humus that forms the most stable part of recycled organic waste.
Humus and the minerals that plants need both carry a weak electrical charge. The electric charge holds the plant food minerals close to plant roots and prevents them from washing away in heavy rain.
Humus is able to control the release of trace elements needed in tiny amounts, and block absorption of poisonous metals in soil so that they do not end up in our food.
Humus stores carbon in soil for very long periods of time.
Humus, in compost, provides a habitat for a soil community of billions of beneficial bacteria and fungi that perform important functions.
Some bacteria species in humus make a ‘glue’ that is able to hold soil particles in a way that improves the flow of water and air through soil. This improves the structure of soil so that plant roots grow more easily. Strong roots help plants to resist the effects of drought and storms.
Mycorrhiza fungi in humus stick like hairs to the roots of plants, helping them absorb water and nutrients in exchange for sugars produced by plants during photosynthesis. Some 95% of perennial plants rely on mycorrhiza for healthy growth.
This method of frangipani propagation is becoming popular with readers, and one of our readers, Margaret, has been kind enough to share some photos of her very successful efforts.
Why choose this method of propagation? Frangipani grown from seed grow more quickly than trees grown from cuttings and, in the same way a family of children or animals can inherit different combinations of their parents’ genes, plants grown from seed may demonstrate different characteristics of parent plants, sometimes resulting in spectacular new varieties. Plants grown from cuttings are an exact copy on one parent. Not only may the flowers vary in colour or form, we have found that the perfumes of different-coloured frangipani also vary.
We have multiple trees of four different frangipani and the orange one reminds me of the smell of ripe peaches, while the deep pink one has a sweet citrus smell, and the pale pink one hardly any perfume at all.
If your frangipani tree has produced a seed pod or two and you would like to try this method of propagation, you can find more information here: Frangipani trees from seed.
Occasionally, garden gurus will say that “beans will grow on the smell of an empty fertiliser bag because they will fix nitrogen in the soil”. This is not true in Australia, where the soil bacteria that is necessary for these legumes to fix nitrogen does not occur naturally. Gardeners are often then disappointed to find that the lower leaves of their beans and peas have yellowed.
French or green beans (and peas) will benefit from the addition of some mature compost and a light application of complete fertiliser when preparing the planting area. Plants need more than nitrogen to be healthy and produce good crops, and compost in soil helps beans resist bean fly.
French beans do well in a sunny position with a soil pH not lower than 6. However, they may need some temporary shade during our heat wave conditions. Regular, deep watering and a 5 cm layer of mulch over the bed will help to keep them growing strongly. Bush varieties of French beans grow best when sown in a block rather than rows, and can be ready to harvest in eight to ten weeks after sowing.
For a continuous supply, sow a small quantity each month listed in the monthly planting guide for your climate.
Sometimes it is necessary to move an established tree or shrub. Deciduous plants can be moved in winter or early spring, and evergreen plants in spring. This is best done in two stages if you have to move an evergreen plant, but sometimes situations arise, due to weather conditions or moving house where a shrub or tree has to be moved urgently.
This advice is for moving trees and shrubs small enough not to require the assistance of mechanical equipment.
Dig a deep trench around the plant you want to move, using a sharp spade to cut through the roots. The trench will usually have to be dug inside the drip-line of the plant, otherwise the root ball will be too large to handle. The drip-line is the area of soil directly below the outer edges of the foliage – where rain runs off the leaf canopy onto the soil. This is where the feeder roots usually lie.
Water the area thoroughly, but do not apply fertiliser. Then prune back the foliage, or remove whole branches in the case of frangipani. This is necessary to compensate for a smaller root ball, so that the plant will not suffer water stress.
If possible, leave evergreen plants in position for about a month, watering it regularly. This will help the plant to produce some feeder roots within the reduced root ball area.
When ready to move the plant, make sure the soil is damp. Get a large piece of hessian, shadecloth or weed mat and some cord. This will help to keep the root ball intact during transplanting. A trolley, or tarpaulin or another large piece of strong fabric will help to use as a sled to drag the plant to its new planting position if the plant is too large to lift into a barrow.
First dig the hole where the plant is to be positioned. Fill the hole with water. This is important for two reasons. How quickly the hole drains indicates whether drainage is good or you will need to plant the tree or shrub in a raised mound. If the surrounding soil is not damp when you transplant, the water you apply after planting will be drawn away from the root ball into the surrounding dry soil, and the plant will look stressed several days after planting.
Work the spade around the trench dug previously, easing the spade further and further under the root ball until you have cut through all the roots.
Place a clear mark on the north-facing side of the plant so that it will be positioned in the same orientation.
Ease the fabric gently under the root ball. It will be much easier if someone helps by slowly tilting the plant to one side. Gather the fabric around the root ball and tie with cord.
Carefully transfer the plant to the new hole positioning it at the same level it was planted previously. Untie the fabric and gently ease it out from under the root ball.
Fill the hole with soil, adding some compost, if available. Do not trample the soil around the plant. Water thoroughly to remove any air pockets around the roots, and apply a 5 cm layer of mulch around the plant, keeping it a hand span from the trunk. Job done.
Staking a replanted tree or shrub will stabilise it until it becomes established in its new position. Gardening Australia has an excellent video on how to support plants using 3 stakes. See: 3 stake method
** Please note: Moving Eucalyptus taller than 45 cm, or other plants that have tap roots is often unsuccessful.
Bees love lavender, and because French lavender* flowers during winter, it provides them with nourishment when there is little else in flower. Lavender is known for its calming effect on people and it has the same effect on bees. A hardy plant, French lavender prefers a gravelly soil with a close to neutral pH. It is an efficient water user and requires little complete fertiliser, suits warmer climates, makes an attractive hedge, and is happy in beds or a large pot. All it needs is a light hair cut when flowering has finished.
Bee numbers are declining around the world. This is a matter for concern for all of us as we rely on bees to pollinate a good number of our fruits and vegetables. As well as growing some French lavender or some winter-flowering annuals, please ensure you keep some clean water available in your garden as bees need clean water, too. Many drown each year from trying to drink chlorinated pool water. A bird bath or large plant saucer, regularly topped up with clean water, is all they need.
* French Lavender (Lavendula dentata) is also known as Toothed Lavender, so named for the edges of its leaves.
With very cold weather set to continue over much of Australia for some time, gardeners can protect young seedlings with an easy-to-make cloche. This simple structure named for the French word for ‘bell’ keeps plants warm on chilly nights and can be easily ventilated so that they don’t get too warm during the day. When the nights are milder, the structure can be easily folded and stored until it is needed again.
Instructions for making cloches can be found here: Cloche for seedlings. ** And remember to leave frost-damaged parts on shrubs until all risk of frost has passed. They may look unattractive but the burnt portions are protecting the plants from further damage.
This cordial is popular with children and makes a delicious mixer for adult drinks.
(yields about 600 ml):
Prep/cooking time: about 20 min. plus chilling..
250 ml pink or yellow grapefruit juice (2-3 fruits)
250 g white sugar
250 ml water
Fresh ginger to taste (I used 2-3 cm)
Juice the grapefruits. Peel the ginger and slice it thinly.
Pour the grapefruit juice into a small saucepan, add the sugar and water as well as the sliced ginger. Bring to a boil and allow to simmer until sugar has completely dissolved.
Remove from heat and let stand for 10 to 15 minutes. Pour through a fine mesh sieve into a sterilised bottle and refrigerate the strained syrup until thoroughly chilled. Seal the bottle. Store in the refrigerator.
To cut the sweetness, dilute with water or soda water and ice cubes.
This week, two readers have asked me about garden problems caused by lack of water. As you know, it is extremely difficult to keep gardens well-watered in drought conditions. However, as plants can only absorb the nutrients they need for healthy growth and ripeness of crops as water-soluble ions, inadequate water is the cause of a wide range of problems, including pest attack.
Bare soil in garden beds and around trees, shrubs and vines allows a lot of soil moisture to be lost to evaporation. A 5 cm layer of organic mulch over beds and around larger plants (keeping it a hand span from the trunk) will prevent water applied to the soil from being wasted. Lawns are greedy and as their roots are close to the soil surface, they take water and nutrients intended for fruit trees and favourite ornamentals. Keep lawns beyond the outer canopy of trees and cover the area under trees with mulch.
A method that we have found very helpful to water mulched beds is to use plastic soft drink and juice bottles to funnel water through mulch directly to the root area of susceptible plants. This is a quick and very efficient way to hand water during drought, water restrictions, heat waves or windy weather. Limp tomato seedlings will freshen up in about 10 minutes after watering by this method.
Simply cut off the base of each container, remove the lids and bury the necks of the containers about 8 cm deep near outer edge of the foliage of plants. Large shrubs may require several containers. Pour water into the container until it begins to drain slowly – an indication that you have dampened the soil in the root area.
Seedlings and pot plants are usually the first to suffer during heat waves, and you can find advice on how to revive stressed pot plants here: Pot plant stress
For organic gardeners who don’t have enough recyclable waste for a productive compost heap, a compost worm farm is the answer.
Compost worms are different from earthworms that tunnel through soil and move into compost heaps after organic matter has been partly processed by microorganisms. Consequently, the term ‘compost worms’ can be confusing to new gardeners. Worm farm (compost) worms require a moister and cooler environment than earthworms (10–30° C.), and feed on a wide range of organic matter, including vegetable and fruit waste (except for citrus and onions), wet paper and cardboard, grass clippings, aged cow and horse manure, soft weeds and hair. Chopping waste into small pieces provides a larger surface area for worms to feed on and speeds up production. The digested waste (worm castings) are a clay-like humus that contains all the nutrients and trace elements that plants need for good health in a form that plant roots can absorb immediately.
Worm castings are Nature’s slow-release, complete organic fertiliser. The more varied the worms’ diet, the better the fertiliser. Simply rake the worm castings into the topsoil on garden beds. As they do not smell, they are the perfect fertiliser for both indoor and outdoor pot plants. They are also a great addition to seedling mixes and, when diluted to very weak black tea strength, the liquid that drains from the worm farm is a fertiliser that gets seedlings off to a flying start.
Worm farming has become a very popular method of recycling and various commercial worm farms are available to suit different situations. Most children find worm farms fascinating and enjoy looking after them.
Commercial worm farms come with complete instructions, a starter colony of worms and edible bedding for the worms. Small commercial farms with several tiers are easily moved into a shed or garage in areas where frosts occur. Or, in frost-free areas, if you can find an old hip bath or large sink, you can make your own worm farm as we have here. Worm farming
Containers with a drainage hole prevent moisture build up in the base of the farm and a waterproof cover excludes light and rain. (Avoid using old carpet or underlay as a cover as these are impregnated with pesticides.)
Add a little water to the farm when necessary to keep the food and bedding damp.
A light dusting of dolomite every few weeks will keep the worm farm smelling sweet and the pH close to perfect.
HARVESTING WORM CASTINGS Worms in farms with stacked trays will move up into the next highest layer when all the food in their tray has been eaten, and it is time to collect the worm castings.
Uncover the worm farm and leave the surface exposed for 15-20 minutes. The worms will move down through the castings away from the light. The castings will contain worm eggs. These are easily recognised as you can see in the photo. They are about the size of the head of a match, or a little bit smaller. Worms don’t lay their eggs in groups like some insects do. They lay them one at a time through the worm castings, but usually close to where they can find food when they hatch. Use a scoop to collect a layer of castings from the top of the farm. A scoop can be made from a 2 litre juice bottle with a handle. Spread the castings onto an old tray by lightly brushing the castings with gloved hands. Check for worm eggs and any small worms that might still be in the castings and put them safely back into the farm. Cover them with a layer of food.
Then tip the collected worm castings into a bucket and collect another scoop full of castings until you have enough to put into your garden bed, or to make ‘worm tea’.