What to grow in August 2019

* For gardeners who do not use moon planting: sow or plant out any of the following list at any time this month, although you may find germination rates are lower when the Moon is in Last Quarter phase..

WARM CLIMATE South of Rockhampton
Before the Full Moon, cabbage, open-headed Chinese cabbage, grain crops, lettuce, mizuna, silver beet, spring onions, tatsoi and dill can be sown or planted out, and rocket and a green manure crop of wheat can be sown directly into beds. Sow chickpea, nasturtium, and sunflower when soil feels warm to touch.
During First Quarter phase, bush and climbing beans, and rosella can be sown. Capsicum, cucumber, eggplant, rockmelon, summer squash, tomato, watermelon and zucchini can be sown in a cold frame or warm, protected area.
During Full Moon phase, carrot, Jerusalem artichoke, potato (Brisbane and areas south), and radish can be sown directly into beds. Asparagus seed, beetroot, rosemary, thyme and watercress can be sown or planted out. Avocado, citrus, macadamia and potted grapes can be planted.

WARM CLIMATE Rockhampton and northwards
Gardeners in very warm areas have time to sow late crops of many varieties.
Before the Full Moon, cabbage, lettuce, parsley, and spring onions can be sown or planted out. Grain crops, NZ spinach, silver beet and sunflower can be sown directly into beds, as well as a green manure crop of wheat or lablab.
During First Quarter phase, capsicum, cucumber, eggplant, parsley, rockmelon, rosella, summer squash, sweet corn, tomato, watermelon and zucchini can be sown or planted out. Bush and climbing beans and sweet corn can be sown directly into beds.
During Full Moon phase, carrot, radish and sweet potato can be sown direct. Avocado, banana, banana passionfruit, citrus and passionfruit can be planted.

TEMPERATE CLIMATE
Sowing and planting this month will depend on whether your area is prone to frosts. Gardeners in Temperate areas with access to a cold frame can get an early start this month with some warmth-loving varieties.
Before the Full Moon, grain crops and mizuna can be sown directly into beds, as well as a green manure crop of clover, field pea, barley, or wheat. Dwarf peas and chamomile can be sown directly into beds in colder areas. Celery, leek and lettuce can be sown in a cold frame.
In frost-free areas, Chinese cabbage, rocket, silver beet, spring onions, tatsoi and coriander can also be sown directly into beds.
During First Quarter phase, capsicum, cucumber, leek and tomato can be sown in a cold frame.
During Full Moon phase, Jerusalem artichoke and potato can be sown directly into beds; also carrot in frost-free areas. Asparagus seed and beetroot can be sown in a cold frame. In frost-free areas, rosemary, thyme, avocado, and potted grapes can be planted.

COOL CLIMATE
August is still too cold and frosty for most plantings.
Before the Full Moon, English spinach can be sown directly into beds, as well as a green manure crop of broad bean (Faba bean) or field pea. Celery, leek and lettuce can be sown in a cold frame.
During First Quarter phase, dwarf peas can be sown directly into beds. Tomatoes and chamomile can be sown in a cold frame. In very cold areas, broad beans can be sown. (See post on when to sow Broad beans and peas for your local climate.)
During Full Moon phase, Jerusalem artichoke and potato can be sown directly into beds, and late season onions can be sown or planted out. Asparagus seed can be sown in a cold frame. Herbaceous perennial crowns can be planted. In very cold areas, deciduous trees, shrubs and vines can be planted.

Citrus gall wasp

Galls or stem swellings on citrus trees need to be removed by pruning by the end of August, as very tiny black wasps emerge from the galls in September and October ready to lay a new batch of eggs in citrus stems. Because these wasps are poor fliers, they tend to reproduce on the same tree unless blown by wind to a new host.
Unlike many other wasps that assist pollination or are pest predators, the citrus gall wasp is a true pest. Eggs are laid in young stems of citrus trees, particularly lemon and grapefruit varieties, and the native finger lime. The larvae remain within the stem, stimulating the growth of cells, and causing a gall or swelling to form on the infested stem by early summer. Trees that are repeatedly attacked will become weaker and produce less fruit.
Originally, only coastal gardens of New South Wales and Queensland were affected, however, this wasp is spreading to other areas of Australia.
Do not add galls to the compost heap. Burn them, or dispose of them in a sealed plastic bag. It is very likely that the gall in the photo missed last year’s pruning because it is unusual for galls to reach that size in one season. As you can see, the tree in the photo is also affected by scale, and it is more common for citrus gall wasp to attack stressed trees. After pruning, water the tree thoroughly, and feed it with a complete organic fertiliser and as much compost as you can spare. A drink of seaweed extract tea will help it to resist further pest and disease attack.

Leaf-eating ladybird

This ugly little creature is the larva of the leaf-eating ladybird. Stressed plants in prolonged hot, dry conditions attract these pests. The larvae become almost black as they reach pupa stage. Both adults and larvae of leaf-eating ladybirds are particularly fond of the Solanum family (tomato, potato, eggplant) and the melon or squash family where they do a lot of damage to leaves.

 

The adult leaf-eating ladybird has 26 or 28 spots in rows across its wing covers. They are slow moving and drop to the ground when disturbed. In summer, if you see the adults on leaves in your garden, be sure to look under the leaves for their eggs. Remove small leaves containing eggs and, on large leaves, use a knife to scrape the eggs into a container. As I dislike spraying my garden, I just squash the adults and larva with a gloved hand.
Unfortunately, the damage done by these ladybirds and their offspring have resulted in many gardeners spraying other species of ladybirds that are voracious pest predators. Both adults and larvae consume a considerable quantity of pests such as aphids, scale and mites, and one type of ladybird feeds on fungus. Peter Chew and his family have an excellent website, Brisbane Insects and Spiders, where gardeners can easily identify which creatures are beneficial to their gardens and which are pests, and includes a Ladybird Field Guide.
The photo below shows both larva and pupa stages of the 28-spotted ladybird.

Flies around fruit bowl

Drosophila-wikipedia Column 8 in today’s Sydney Morning Herald stated that Sydneysiders’ kitchens have been infested by fruit flies, stating that, “They emerge from fruit and hang around all summer”. The flies referred to are not fruit flies, they are the very small vinegar or ferment flies (Drosophila). Genuine fruit flies are kept out by fly screens. Vinegar flies emerge from fruit, tomatoes, etc. as grubs (larvae) and require pupation outside the fruit in order to complete their life cycle as a fly. If these tiny pests are a persistent problem, there must be a breeding ground nearby or the kitchen needs more regular cleaning.
Vinegar flies are attracted to the smell of yeast in fermenting organic materials and drains. To eliminate the problem:

  • Do not keep fruit at room temperature in warm, humid weather
  • Cover compost and garbage containers
  • Regularly rinse out garbage containers
  • Rinse beer and wine containers before recycling
  • and treat drains with an enzyme product to break down thick scum where they can feed and reproduce.

Genuine fruit flies, the Mediterranean Fruit Fly (Ceratitis capitata) and Queensland Fruit Fly (Dacus tryoni) cause a lot of destruction in gardens. They require pupation in soil after the maggots emerge from fruit. To reduce the problem of genuine fruit flies, collect all fallen fruit, put it in a sealed black garbage bag and leave the bag in the sun for three or four days to cook the larvae (and encourage your neighbours to do the same). Never put infected fruit in the compost container.

Ladybird larvae

Stressed plants attract pests and where you find pests you will also find beneficial insects that feed on pests. During extreme weather conditions you may notice some of these strange little creatures on various plants in your garden.

LBtransverse_lvLBcommspot_lvLBstriped_lv

LBsteelblue_lvLBmealybug_lvLBfunguseat_lv

These are not pests – they are juvenile ladybirds

Both juveniles (larvae) and adult ladybirds eat vast amounts of aphids, various types of scale and mites. One species eats fungus, including powdery mildew. The white, fluffy species eat mealy bugs. They are difficult to distinguish from the pests they devour. Australia exports this variety of ladybird to the USA to help with their mealy bug problem.

These are some images of the pupa stage, just before adult ladybirds emerge. Ladybird larvae have an attachment at the end on their abdomens that allows them to stick to a leaf surface while they pupate.

LBsteelblue_pLBfunguseat_pLBcommspot_pLBvariable_p

 

 

 

 

Lady bird larvae often seek shelter from birds in the curled leaves that citrus leaf miners produce. Remember, if you decide to use chemical or organic sprays to treat pests that you will also kill beneficial insects and their offspring. There is only one species of ladybird that is not helpful in the garden: 26 or 28 spotted ladybird.

 

For lots more information about lady birds, see: Ladybird Field Guide

Yellow leaves – potted citrus

irondeficiency

A reader wanted to know what what is causing yellowing of new leaves in her potted, dwarf lemon tree. From the photos she e-mailed, it does look like this tree has an iron deficiency, as yellowing is showing in the young leaves. This can be caused by a number of conditions:


a) potting mix (or soil) that is too alkaline from excess bio-char or calcium in the mix or fertiliser containing a lot of poultry manure
b) cold and wet soil or growing mix
c) if there is a build up of fertiliser salts from synthetic fertilisers, or
d) where there is an excess of potassium from synthetic fertilisers or over-use of seaweed liquid fertiliser.

The first thing to do is check that your pot has ample drainage. Large pots should not sit directly on a hard surface. While smaller pots usually have ample drainage holes around the sides at the base of the pots, large pots often have only one large hole in the base and this can easily become blocked resulting in poor aeration and/or a concentration of fertiliser salts if synthetic fertilisers have been used. Large pots should have pieces of tile placed under the pot to allow a small space between the base of the pot and the verandah or paving. If you notice crusting around the top of the soil line (fertiliser salts), flush the plant with clean water, once drainage has been improved.

The next step is to check the pH of the mix with a test kit. A suitable pH is important to all parts of your garden as the pH in soil or mix controls the availability of nutrients. Test kits are very economical to use and readily available from larger nurseries. If you find that the pH is above 7.2, you could repot the tree using an organic-registered potting mix as organic matter is an important source of iron. However, to do so may result in the loss of this crop of fruit.
The addition of flowers of sulphur (elemental sulphur) is the usual way to reduce pH in soils, but it is easy to overdo this in potted plants. You can apply iron chelates (the form of iron in organic compost) to the mix in the pot at the recommended rate. Citrus trees do not absorb iron chelates well through foliar spraying. Or, you can fertilise the tree with a weak solution of Multicrop’s Ecofish. This is an organic-registered liquid fertiliser that contains soluble iron and has a low pH, qhich will help to reduce the pH in the pot. Ecofish contains iron, manganese, sulphur and zinc (trace elements needed by citrus). Manganese deficiency is also caused by high pH or poorly-drained soil.

Red-shouldered beetles

OLYMPUS DIGITAL CAMERA The warm, dry weather has enouraged this small native beetle (Monolepta australis) to move into gardens. As their common name suggests, these yellow beetles have a bright red stripe across their shoulders and a red spot on their wings. They arrive in a large swarm and choose one or two stressed plants to feed on. We have noticed that they frequently choose plants with white flowers. Although these beetles are only 6mm long, their sheer numbers enable them to skeletonise small to medium shrubs in a very short time before moving on to another property. Monoleptas are difficult to control because sprays that will kill the beetles will also kill beneficial insects visiting plants at the same time.
If the plant being attacked is not too large, you can get rid of these beetles by using a stick to knock them into a container of soapy water. Because of their fondness for the colour white, many beetles will drown themselves in a white container full of water left near the target shrub. (Don’t add soap to this water or it will kill bees that stop by for a drink.) The only way to protect your garden from attack by these beetles is to keep shrubs watered during dry spells, and keep the garden surface mulched to prevent moisture loss through evaporation.

Lime Sulphur

yellrose1 Agricultural lime or elemental sulphur are recommended to modify soil pH to a range that suits healthy growth of particular plants. A reader recently asked me if “Lime Sulphur” was suitable to use around roses in her organic garden.
‘Lime Sulphur’ or ‘Lime Sulfur’ is a fungicide/pesticide formed from reacting calcium hydroxide (made from adding water to quicklime) with sulphur. It is usually applied when roses are dormant as it can burn foliage.
Hydrated lime is very reactive and should not be used where plants are growing. Lime Sulphur solution is quite alkaline (pH 10.5–11.5) and corrosive. Gloves, goggles, face masks and protective clothing must be worn as the pesticide is very irritating to the eyes, skin and respiratory passages. See the Material Safety Data Sheet for this product.

Plants are affected by diseases when they cannot get enough of the elements (including sulphur) they need for a healthy immune system either from inadequate fertiliser, or an unsuitable soil pH (because pH controls the availability of different nutrients to plants), or soil that is either too dry for the roots to absorb the nutrients, or is waterlogged and very acidic.
Although some sources state that Lime Sulphur fulfils requirements of organic gardening groups, the ‘Australian Certified Organic Standard 2010‘ lists Lime Sulphur as a restricted product and notes that it has a potential impact on beneficial insects.
My advice is to maintain a moderate amount of well-made compost in your topsoil, where compost holds all nutrients (including sulphur) close to plant roots; adjust irrigation and soil pH, and provide suitable amounts of complete organic fertiliser. In the meantime, if your plants have a serious fungal problem, I suggest you use Organic Crop Protectants’ organic-registered ‘Eco-fungicide’. It won’t damage your plants or your soil, and it is kind to beneficial insects.

Cabbage butterfly update

cwbdecoy Cabbage white butterflies have had a lovely time with my broccoli this year. There are several conditions that make brassicas very attractive to these pests and the brown cabbage moth. See Cabbage white butterfly.
My problem was that I inadvertently added some very alkaline compost to that area of the garden, (See recent post on Compost pH) and it is taking a while for the soil to get back to a neutral pH.

After spending a week or so removing eggs, squashing tiny caterpillars, or feeding larger ones to the chooks, I remembered a tip someone gave me long ago to deter these pests but have not needed to use before. The tip was to slip the plastic clips that seal loaves of sliced bread onto the edge of some of the Brassica leaves. White seals to deter the C W butterfly and beige ones for cabbage moth. The theory being that the adult butterflies and moths will “think” that eggs are already being laid on these plants and they look for another food source for their larvae.
My broccoli plants are looking healthier already and I have not found any more eggs under the leaves, but I don’t know if the seals are working or the pests are no longer present in our area. Has anyone else tried this tip?

Root knot nematodes

Nematodes that damage roots in the vege patch, are minute worm-like creatures, also known as eelworms. The female nematodes penetrate plant roots causing lumps to form on the roots, which affect the water-carrying ability of the roots. (These are not to be confused with the nitrogen–fixing lumps that form on the roots of legumes, see Fixing nitrogen). Root knot nematodes are more likely to occur in warm climates in soils that are low in organic matter, especially where a proper crop rotation has not been practiced.

Treatment
Each female nematode can lay up to 2000 eggs, and numbers can multiply quickly. Give affected plants a foliar feed of seaweed extract tea. Seaweed contains plenty of potassium that helps to strengthen cell walls and improves plants’ resistance to pests and promotes root growth. Remove all weeds. Some weeds are hosts to these pests and can transfer viruses to plants.
Affected plants must not be allowed to become water-stressed. Badly affected plants will have to be removed. Make sure the soil is damp so that soil clings to the roots. Place plants (with attached soil) into a garbage bag. Seal the bag, leave in hot sun for a few days, then place it in the garbage. Do not compost these plants. Once the crop is harvested, proceed with methods for prevention (see below).

Prevention
Allow 3 years between growing any member of the tomato/potato or melon/cucumber families in the same patch of soil. During this break, grow a green manure that is a ‘bio-fumigant’. ‘Bio-fumigants are green manures that release a gas that is toxic to nematodes. They are grown to knee height and chopped up and mixed through top soil, then covered with mulch. Green Harvest have seed for BQ Mulch (sown in cooler months) and cowpea (sown in warmer months) that control nematodes. Indian or brown mustard (Brassica juncea) and non-GM rapeseed (Brassica napus) are also effective bio-fumigants. Forget marigolds, they are more effective against northern hemisphere nematodes. During the 3 year break, brassicas or corn can be grown in the treated bed, if you have limited garden space.
When preparing beds, add a 5 cm layer of organic compost to the bed surface and cover it with organic mulch. Beneficial organisms in compost are pest nematode predators, and mulch keeps compost damp to allow microorganisms to work on restoring soil to health.