When to water?

A common question asked by gardeners is how often should they water their garden.
Unfortunately, limited watering times imposed by water restrictions have encouraged some gardeners to rush around giving everything a light watering during the allocated time.
A light daily watering is one of the worst things you can do for your garden. It only encourages plant roots to stay close to the soil surface – the area that dries out first.
Plants watered in this way wilt quickly on hot, or windy, days – encouraging gardeners to perpetuate the cycle.
If you use mulch, very few plants need watering every day. Mulch not only prevents water loss through evaporation from the soil surface, it assists the capillary movement of water through soil. Seedlings will probably require daily watering through the warmer months because they have very small roots systems.
The most reliable way to decide if plants need watering, is to poke a finger, up to the first joint, into the soil or potting mix. If the soil feels damp, the plants don’t need watering. If the top centimetre or so feels dry, give the plants a thorough watering, under the mulch. When watering shrubs and trees, water under the outer edges of the mulch where the feeder roots lie, not near the trunk. Plants watered in this way develop stronger root systems, and will be more resistant to adverse climate conditions.
Many plants slow their growth or become dormant in winter, and they need less watering than in warmer months. More pot plants are killed by over-watering, than under-watering. When the surface of potting mixes feel dry, small pot plants can be watered, at any time, with water collected while waiting for the shower to warm, as long as you remove the bucket before getting in the shower and making the water soapy. Dunk the pots into the bucket until bubbles cease to rise from the water surface. Overhead watering of indoor plants can encourage fungal diseases, especially in the cooler months.

The importance of humus

Soil without humus is lifeless – it’s dead soil. Humus, the indigestible part of decomposed organic matter, literally converts soil into a living thing because it provides a habitat for beneficial fungi that feed nutrients to many plant families, and microorganisms that keep soil-borne plant diseases under control. It also keeps soil more moisture retentive, yet better drained; improves soil structure; holds nutrients in a form that is easily absorbed by plants; insulates plant roots by keeping topsoil cooler in summer and warmer in winter, and acts as a buffer against extremes in soil pH through a complex exchange of electrically-charged particles in soil. Regular replacement of humus in soil is absolutely essential to healthy plant growth. Humus can be added to soil as compost, green manures, well-rotted, herbifierous animal manures, poultry manures, organic mulches, decaying roots and plants.
The vegetable garden will require the lion’s share of organic matter, but it is very important to fruit trees, and many foreign plants, too. Many Australian natives prefer humus supplied through leaf litter, or leaf mould. Plants from arid soil areas have evolved to require only small amounts of humus.

Applying compost

The best way to add humus to your garden soil is mature compost, which is a mixture of worm castings, beneficial microorganisms, and humus. Compost is not only a fertiliser; it stimulates soil organism activity by providing them with food. Compost made from a variety of sources contains all the nutrient elements required by plants but, for those of us that don’t have an unlimited supply of compost, green manures are an excellent substitute.
In vegetable gardens, a 3–5 cm layer of compost can be applied to beds and mixed into the top 15 cm of soil. If mature compost is in short supply, adding compost to the planting hole or furrow when planting out seedlings or sowing seed will get your plants off to a flying start. Compost can be applied this way to flowering annual and spring bulb beds, too.
Under fruit trees, and around roses and herbaceous perennials, compost should be applied to a damp soil surface under the outer part of the tree or plant foliage canopy – i.e. not close to the trunk. Don’t scratch it into the surface. Many trees and shrubs have feeder roots close to the soil surface and these are easily damaged. If you have plenty of compost, it can replace the tree’s fertiliser, except for an annual application of seaweed tea. If you don’t have a lot of compost, it can form part of the fertiliser application. Every bit of compost that you can spare is very valuable.
The compost should then be covered with 5 – 8 cm of organic mulch to keep the compost damp – also keeping the mulch well clear of the trunk. When compost dries out it loses a lot of its benefits. The mulch will break down to contribute to good garden loam, but its most primary function is to keep the soil surface and compost damp.
If you apply compost annually under your fruit trees and shrubs, you will find that “so-so soil” will steadily convert to dark, sweet-smelling loam full of earthworms – just the type of soil these plants love. Your trees and shrubs will also be more resistant to pests and diseases.

Taking cuttings

Full Moon phase is a good time to take cuttings, and cuttings can be taken from deciduous plants from hardwood stems, while pruning. Always trim to a horizontal cut at the bottom of the stem to be used for cuttings, and make a slanted cut at the top, otherwise it is easy to plant deciduous cuttings upside down. The chosen section should contain 5 or more nodes (joints in the stem) to allow for trimming.
Fill pots with a sandy potting mix, and trim the base of the cuttings (with a horizontal cut) to just below a node. Position the cuttings around the inside edge of each pot spaced far enough apart to allow roots to spread. Try to have two nodes below the level of the potting mix. Water gently to settle the mix around the cuttings. Keep potting mix just damp, and keep cuttings in a warm, well-lit area out of direct sunlight and wind until the cuttings show signs of growth. Carefully move them into separate pots and feed with weak fertiliser tea, until ready for planting out.

Winter pruning

A Full Moon phase during winter is a good time to prune most deciduous plants. From 19th of this month is a good time to prune dormant trees and vines that tend to bleed (weep sap) if pruned in late winter. These include grapes, kiwi fruit, mulberry, birch, conifers, frangipani, maple and poplar. Pecans, which bleed readily and require minimal pruning, are best pruned during Last Quarter phase (from June 26th) when sap flow is lowest. Almonds should also be pruned early in winter because they flower earlier than other Prunus species. Other deciduous fruit trees can be pruned in winter with the exception of apricots and cherries. These trees are prone to bacterial canker if pruned when sap flow is low and cuts are slow to heal. Young apricot and cherry trees can be pruned in spring during First Quarter phase, and mature trees pruned after harvest during a Full Moon phase. Deciduous fruit trees grown for spring flowers rather than fruit are pruned during a First Quarter phase, after flowering.
It is a good idea to keep a container of methylated spirits with you when pruning and regularly wipe the blades of your pruning tools to avoid the risk of spreading and bacteria or fungal spores from one plant to another.

Pruning roses
In most areas, bush roses can be pruned during a Full Moon phase in winter, after they become dormant. If you have removed dead wood, suckers and crossed branches during the growing season, little winter pruning will be required. Where frosts are common, or rose canker (dieback) has been a problem, it is better to prune bush roses as late as possible – at the first sign of new growth when sap flow is higher. Then prune, with slanting cuts, during First Quarter phase to encourage strong growth. This will help reduce dieback because the fungus that causes rose canker lives on rose thorns. Roses are more susceptible to infection by this fungus when sap flow is slow and pruning cuts heal slowly. Careful pruning is the only way to avoid dieback, as there is no treatment for the fungus.
Climbing roses that are floribunda or hybrid tea sports can be pruned at the same time as bush roses, but climbers that only flower in spring are pruned before a Full Moon, after flowering.

Cottonycushion scale

These sap-sucking pests are can be found on the twigs and branches of a range of plants, including fruit trees. The pests themselves may not attract much attention unless the plant is heavily infested because they are reddish-brown in colour with black hairs, and only 5 mm in length. The part we notice as a pest is actually the scale’s egg sac – a grooved, white, wax structure, larger than the insect itself. The egg sac will contain up to hundreds of red eggs. (See photos below).

Before treating these pests – check that you haven’t confused them with the larvae of the mealy bug ladybird, which are also white and fluffy. Ladybirds and their larvae consume an enormous amount of scale insects and aphids, but many of the larvae are killed when they are confused with pests. Many pest predators are killed where copper sprays are routinely used, and scale infestations commonly follow spraying for other pests.
When the cottonycushion scale prepares to lay her eggs, she fixes herself to the twig. Give the white structure a poke, if it doesn’t move, it’s scale – ladybird larvae will scuttle off. When temperatures are below 24° C, and pest predators are absent, cottonycushion scale can be suffocated by spraying with white oil at 10 ml per litre of water. This will not kill the eggs, and the spray will have to be repeated in two weeks, to catch the newly hatched scale.
In warmer weather, suffocate spray with enough fine potter’s clay dissolved in water to make it cloudy. Pest infestation is a sign that plants need an improved fertiliser and/or watering program, or that you need to adjust your soil pH.

Planting roses

Roses are available for planting now. If possible, avoid purchasing bare-rooted roses before the end of June, as roses that have been lifted before they are fully dormant do not usually grow well. If you live in an area where frosts occur, it is better to plant them at the end of winter. Planting of potted roses can be delayed until spring where frosts are severe. Also avoid planting roses during wet weather, when soil will become compacted.
Roses need a well-drained soil, and following the guidelines for planting trees and shrubs apply to roses. See “Planting trees, shrubs and vines”, under Ornamentals.
If new roses have not been pruned before purchase, leave any pruning required until the end of winter, at the first signs of new growth, or until frosts have passed. If new roses are pruned early and frost damages the plants, you will have very little to cut back to. Climbing roses are pruned after flowering in spring. If pruning at the end of winter, prune new roses during First Quarter phase when sap flow is higher and growth response will be faster. If frost is not a problem, new roses can be pruned during Full Moon phase during winter.
If you are replacing a sick rose, remove soil from the planting area beyond the reach of the sick rose’s roots, and replace it with soil that has not grown roses before.

Planting trees, shrubs and vines

dripline Winter is the best time to plant deciduous trees, shrubs and vines, including roses and fruit trees. Evergreen plants do well if planted in spring in cool and temperate climates, or in early autumn where summers are very hot. Moon planters will plant these during Full Moon phase for best results.
Always make planting holes wider than deep. Feeder roots are situated under the outer foliage canopy where rain drips from the plant. A wide planting hole allows the easy spread of roots as the plant grows. Wide holes are extremely important where soil is heavy. Mulch should also be applied to the outer canopy area, not near the trunk. Mulch against the trunk can cause collar rot.
Having dug the planting hole, fill it with water and leave it for an hour or two. This practice serves two purposes. It allows you to check that the area is well drained, as few plants grow well in waterlogged soil. It also prevents water applied after planting being drawn away from the plant into surrounding drier soil. If some water remains in the bottom of the hole, plant the tree or shrub in a mound to improve drainage. If a lot of water remains in the hole, avoid planting in that spot until drainage is improved.
Don’t plant any deeper than the tree or shrub was in the pot. Bare-rooted plants will have a change of colour on the trunk that indicates the original planting depth. This will ensure that any graft is positioned above ground level. To avoid planting deeper, lay a garden stake across the top of the hole and position the plant so that the original depth is aligned with the bottom of the stake. If necessary, make a mound of soil in the bottom of the hole to that the original planting depth can be repeated. Spread the roots of bare-rooted plants over the mound before filling.
Fill in the hole, occasionally jiggling the trunk of bare-rooted plants to avoid air pockets around the roots, and mix some compost or worm castings through only the top 10 cm of soil. Organic matter in the bottom of the hole will cause the plant to sink as the organic matter breaks down. If you do not have compost to spare, place some well-rotted horse or cow manure on the soil surface, under the outer canopy, and cover it with 5–7 cm of organic mulch. The addition of organic matter when planting perennials is very important, as many foreign plant families (exotics), in particular, rely on a beneficial soil fungi called mycorrhiza to supply their roots with nutrients and water, and mycorrhiza live in organic matter. Without organic matter in soil, plants can struggle to absorb what they need for healthy growth, and will be more prone to pests and disease. Australian natives will benefit from the application of some leaf mould around them.
Gently firm soil around the plant, but do not trample the soil as roots can be damaged. Water gently, to settle soil, before applying mulch. Do not apply any extra fertiliser at planting time, but an application of seaweed extract tea can help reduce transplant shock.

Seed not germinating?

Seeds lose their vigour over time and, they can deteriorate more quickly than they should if storage temperatures or moisture levels have been unsuitable. If a batch of seed has not germinated well I do a germination test on some of the seed to see if it’s worthwhile trying another crop.
All I need for this is a wide mouthed screw-top jar, with a lid, and some cotton wool.
testgerm.jpg I place the cotton wool in the bottom of the jar, and add enough water to wet it thoroughly – but not enough to allow it to float in the water. Seeds absorb a lot of water during germination, and inadequate moisture alone can cause germination failure.
Then I sprinkle some of the seed from the suspect batch over the cotton wool. If the seeds are large, such as corn or cucurbit seed, I use the end of a pencil to press the seed firmly onto the surface of the cotton wool, so that they have good access to moisture. This is unnecessary with small seed.
When I replace the jar lid I have a miniature glasshouse. Most seeds require dark for germination; and I place the jar in a dark cupboard that is not opened frequently. I check the jar every three days for signs of activity. Large seeds absorb a lot of water. To test if the cotton wool is still moist and the jar is too tall for a finger test, I roll a piece of paper into a tight tube and touch the end if the tube to the cotton wool. If the end of the paper tube does not absorb water, I add a few drops before resealing the jar.
Some vegetables such as most lettuces, cape gooseberry, seakale, shiso and tomatillo, and some herbs require light for good germination. For these seeds the jar can be kept in a well-lit room. Seed packets will indicate the best position for the test jar.
Most common varieties of vegetable seeds will show activity in a fortnight or so, but some, including capsicum, carrot, celery, eggplant and parsley can require a month for germination to occur.
If the majority of the seeds show signs of germination, the problem is more likely to be the growing mixture, lack of adequate moisture, or unsuitable soil or growing mix temperatures. If germination is poor or the seeds don’t germinate at all, and the seed was purchased recently, the supplier should be contacted to replace the seed.
To reduce problems with seeds, packets should be kept in a cool stable environment where they are protected from moisture and pests. We find that metal biscuit tins make suitable storage containers. The tins are kept in a cupboard in the centre of the house where temperature fluctuations are minimal. We have to store a lot of seed, but one tin or sealed plastic container would be sufficient for most households.

Crop rotation

Crop rotation is the practice of allowing a minimum of three years between growing a particular family or group of plants in the same patch of soil. This practice is essential to maintaining healthy soil because it prevents the build-up in soil of pathogens that cause soil-borne plant diseases. Plants weakened by diseases also attract pests. Many modern farmers have forgotten the importance of crop rotation. The trend is towards monoculture and these farmers have to rely on stronger and stronger chemicals in an effort to cure plant pest and disease problems.
There are eight main groups of plants that are commonly grown in vegetable gardens. Some groups can be grown together but others, such as legumes and the onion family, don’t make good neighbours.
If you find that pests and disease are repeatedly affecting your vegetables, and crops are disappointing, try the crop rotation below and you will find that your garden rewards your efforts. This rotation has six sections and includes a green manure grain, plus a legume green manure if you don’t want to grow your own peas and beans. The green manures are included because they recycle nutrients, replenish organic matter in topsoil, and help inhibit soil pathogens. In this rotation, legumes precede the tomato family because broad beans inhibit a fungal wilt that affects tomatoes. Organic matter assists in keeping soil healthy because it provides a habitat for beneficial microorganisms that keep disease organisms under control and improve soil structure.
Section 1:
Legumes – peas, beans, broad beans, or a green manure legume.
Section 2:
Solanaceous – Tomato, capsicum, chilli, eggplant, pepino, potato. (Some tomato family diseases can also affect Strawberries.)
Section 3:
Crucifers – broccoli, Brussels sprouts, cabbage, Chinese cabbage, cauliflower, horseradish, kale, kohlrabi, mizuna, mustards, radish, rocket, swede, turnip.
Section 4:
Green manure grain – such as barley, cereal rye, corn, millet, oats, sorghum, or wheat – depending on the season. Sweet corn can be grown in Section 4 if you have plenty of compost and don’t need to grow a green manure grain.
Section 5:
Chenopod family – silver beet, beetroot. (Winter spinach can follow a summer crop of beets as long as this group is not grown in the same bed for another 3 years.) Also the Aster group – lettuce, chicory, endive, globe artichoke, Jerusalem artichoke and sunflower.
Section 6:
Umbrelliferous – carrot, celery, coriander, dill, fennel, parsley, parsnip. Also the Allium family – all chives, garlic and onions.

Cucurbits – cucumber, gourd, marrow, pumpkin, rockmelon, squash, watermelon, zucchini. These, except for pumpkin, can be sown with group 5 or group 6, but not both. Pumpkins are best grown on their own because the vines are very vigorous and the roots give off compounds that can deter some other plants. Dill can also be grown with Section 3 to deter cabbage pests. Sweet corn is a good companion for cucumber or beans.

When the legumes are finished, group 2 can be planted in that bed. Group 3 replaces group 2 and so on, with all the groups moving up one bed. If you only have three or four beds, divide some of the beds proportionately, to suit your food preferences. Once your soil is restored to health, you can adjust the rotation to a three or four year one that suits the type of vegetables you prefer to grow, as long as you allow at least three years between the same group.
Crop rotation should also be practiced with flowering annuals and some perennials. Cinerarias and zinnias are related to the lettuce family, petunias are related to the tomato family, and stock and wallflower are crucifers. These plants can succumb to the same diseases that affect the vegetables in that group. Carnations and dianthus can be affected by a wilt disease if they are always planted in the same soil, and carnations, dahlias and irises can also suffer a stem rot disease if crop rotation is not practiced.