A reader has asked about powdery mildew on zucchini plants and fungus-eating ladybirds:
Hi. Wonder if you can sort this.
1. Most fungi need moisture and organic material. This seems to be supported by my zucchinis which seem to get worse powdery mildew when I get water on the leaves. I have read that they like dry weather. Is there evidence for either opinion?
2. Some people say that the ladybirds that feed on this mildew spread it by carrying spores, others reckon they are a controller, eating the fungus down. What is the evidence please for either of these?  Many thanks, Barb

Powdery mildew is likely to occur on stressed plants in humid weather when temperatures are between 11-28° C. and, once established will continue to affect the plants even if weather becomes dry. Avoid wetting leaves whenever possible Barb. However, because they like low-humidity weather, it doesn’t mean that they are drought tolerant. Zucchini and some other members of the cucurbit family (melons and squash) produce a lot of foliage and need plenty of water and fertiliser. An efficient way to water this group of plants without wetting the leaves is to put a large drink container (with the base and cap removed) neck downwards near the roots so that all the water goes directly to the root area where it is needed, (see photo). Keep topping up the container until it empties slowly.
The yellowish ladybirds with 26 or 28 spots are the only pests of the ladybird family. They eat the leaves of stressed plants of cucurbits. The beneficial fungus-eating ladybird and larvae can be clearly distinguished from the pest in the photos below. From the far left is the ‘Fungus-eating ladybird’, then the leaf-eating ’26 spot Ladybird’ that damages plants. Next is the larva of the ‘Fungus-eating Ladybird’, which also eats fungus and, last of all is the prickly larva of the ’26 spot Ladybird.

Rather than blame the fungus-eating ladybird for spreading the disease, gardeners should check that their plants have sufficient water and nutrients to avoid stress, and the soil pH is suitable for them to absorb what they need for healthy, disease-resistant growth. Also see Powdery Mildew for treatment of this disease.

Last October I updated the warning about pyridine herbicides that can damage or kill both food crops and decorative plants. Unfortunately, some readers have since had plant damage after inadvertently purchasing manures or mulch that contain one of these herbicides, despite a NSW government website stating that no damage has occurred in Australia.
As a result, I am posting a reminder.
Pyridine herbicides are only effective on broad-leaf plants, but the chemicals remain active in mulch cut from sprayed pastures and in manure from animals that have grazed on sprayed pastures until the chemicals are broken down by soil microbes. Of particular concern to home gardeners and councils that recycle waste into compost for agricultural and domestic use are the products containing aminopyralid, clopyralid and picloram because they are quite persistent, and residue from these herbicides can damage plants for up to 24 months. However, because the Australian Pesticides and Veterinary Medicines Authority (APVMA) regards the person who sprays the herbicide as the ‘end user of the product’, any warnings are limited to product labels without any regard for unsuspecting gardeners who, in good faith, purchase mulch, compost or manures contaminated with the herbicide, and who may not recognise the cause of the damage to their crops because they have not personally used any herbicides.
A recent check of their website shows that the APVMA has registered 2 pyridine herbicides containing aminopyralid, 62 herbicides containing clopyralid, 60 containing picloram, 28 containing fluroxypyr, and 81 containing triclorpyr – an impossible list to check through before purchasing mulches, manures or compost. The entire tomato family, lettuces, sunflowers, spinach, strawberries and legumes are particularly susceptible to damage from these herbicides, which can also affect a range of ornamental plants.
To protect your garden from pyridine herbicide damage: only use aerobically composted manures on gardens. Aerobic composting requires weekly turning or stirring to ensure the composting process is carried out by microbes that require oxygen. Breakdown of the herbicide will be very slow in compost heaps that are not aerated.
Certified-organic mulch does NOT contain any herbicides. Mulches from uncertified sources are high-risk products because the drying and baling of mulch materials eliminates microbial action, and the herbicide will still be active.
If you are unable to purchase certified-organic mulch, test the safety of the product by sowing some seasonally legumes in pots containing certified-organic potting mix (with the manure mixed through it) or covered with the purchased mulch. Keep the test pots well-watered to eliminate other sources of stress. Symptoms to look for are:
Poor germination or death of seedlings, twisted, cupped or elongated leaves and twisted growth, misshapen pods.

If you find that the mulch has been affected, use it on beds that you can leave fallow until aerobic microbes in topsoil break down the herbicide or, if space is limited, compost it aerobically. Notify your supplier of the problem with the product.
The only safe compost to purchase is certified-organic compost.

Further information:
Examples of pyridine herbicide damage

You can find Australian product names of these herbicides by going to the APVMA’s Public information (PUBCRIS) page. Under product type select ‘herbicide’, then type aminopyralid, clopyralid or picloram in the active constituent panel. Click ‘Search’.

The NSW Government has been aware of the problems with these herbicides in Australia since 2005: see  Organic

Happy New Year to all my readers. January and February can be tricky months for gardening in some parts of Australia, and gardeners will have to adjust their planting to suit local climate conditions. If it is too hot to grow things in your area, use the time to do a good job of preparing beds for strawberries, leeks and winter vegetables.
The following gardening advice is an abbreviated list for vegetables, fruit trees and some culinary herbs that can be planted in January in Australia and New Zealand. A comprehensive guide that includes planting times for the entire garden, as well as when to fertilise, prune, take cuttings or divide plants, can be found in my book Easy Organic Gardening and Moon Planting. If you are not sure which climate zone you live in, please see Climate Zones for more information.

Warm climate – South of Rockhampton
Before the Full Moon, silver beet (pre-soak seed), and sunflower can be sown directly into beds, as well as a green manure crop of adzuki bean, cow pea, lablab, millet, mung bean, pigeon pea, Japanese millet, or sorghum. Leek can be sown in late January.
During First Quarter phase, eggplant, rockmelon, summer squash, tomato, and watermelon can be sown, also cucumber in late January. Bush and climbing beans, and sweet corn can be sown directly into beds.
During Full Moon phase, lemon grass, mango, pineapple and watercress can be sown or planted out. Beetroot (pre-soak seed), carrot, parsnip, potato and radish can be sown directly into beds, also seed potatoes in Brisbane and areas south.

Warm climate – North of Rockhampton
Before the Full Moon, a green manure crop of adzuki bean, cowpea, lablab, mung bean, pigeon pea, Japanese millet, or sorghum can be sown in suitable areas. Sweet corn can also be sown as a green manure crop, and slashed when it is knee high.
During First Quarter phase, sweet corn can be sown directly into beds where heavy rains will not damage pollination.
During Full Moon phase, lemon grass and mango can be sown or planted out.

Temperate climate
Before the Full Moon, Brussels sprouts, leek and spring onions can be sown or planted out. Cabbage, suitable lettuce, and silver beet (pre-soak seed) can be sown directly into beds, (also nasturtium and sunflower in warmer areas), as well as a green manure crop of cow pea, millet, mung bean, pigeon pea, Japanese millet, or sorghum.
During First Quarter phase, bush and climbing beans and sweet corn can be sown directly into beds. Cauliflower, cucumber and leek can be sown or planted out, also rockmelon, summer squash, tomato, watermelon, and zucchini in warmer areas.
During Full Moon phase, beetroot (pre-soak seed), carrot, parsnip and radish can be sown directly into beds, and lemon grass and watercress can be sown or planted out. Pineapple, potato and mango can also be sown or planted out in warmer areas.

Cool climate
Before the Full Moon, Brussels sprouts, leek, lettuce, spring onions, sweet basil and parsley can be sown or planted out. Cabbage, grain crops, lettuce, silver beet (pre-soak seed) and dwarf sunflower can be sown direct, as well as a green manure crop of mung bean or millet. In colder areas, bulb fennel, open Chinese cabbage, dill, mizuna, and tatsoi can also be sown directly into beds.
During First Quarter phase, broccoli, cauliflower and zucchini can be sown or planted out, and bush and climbing beans can be sown directly into beds (also peas in colder areas).
During Full Moon phase, beetroot (pre-soak seed), carrot, parsnip, and radish can be sown directly into beds, and dandelion, mint, sage, and watercress sown or planted out (also pyrethrum in colder areas).

December has been a very busy month on our farm and I have not had time to write any posts. However, I do not want December to go by without wishing you a very safe, happy and healthy festive season, however you and your family choose to celebrate it,

– and to wish all of you and your gardens the very best of health in 2012.

As December is a very busy month in many homes, make sure your garden is well-mulched so that you don’t have to water the garden as often. Check when you buy mulch hay, if it is not certified-organic, that it does NOT come from pasture that has been sprayed with a pyridine broad-leaf herbicide. (See Herbicide problems)

Lettuce and cucumber are foods that tend to have a cooling effect on the body. However, It can be too hot for lettuce to germinate and grow well in warmer areas of Australia during summer, although some of the loose-leaf varieties are more heat tolerant. Keep lettuce seeds in an airtight container in the fridge to assist germination in warm weather, and choose a cool, semi-shaded spot to grow lettuces in containers where summer weather is hot.
If your area has a wet season in the next few months, it might be wiser to not sow sweet corn this month, as heavy rain will prevent good pollination. Corn of any variety can be sown as a green manure crop, though, because green manure plants are cut down when about knee high. In cool climates, there is still time to plant fast-maturing varieties of pumpkin, rockmelon and watermelon. Seed for these can be ordered from Phoenix Seeds in Tasmania (PO Box 207 Snug, Tasmania 7054).
The following gardening advice is an abbreviated list for vegetables, fruit trees and some culinary herbs that can be planted during December in Australia and New Zealand. A comprehensive guide that includes planting times for the entire garden, as well as when to fertilise, prune, take cuttings or divide plants, can be found in my book Easy Organic Gardening and Moon Planting (Scribe Publications, 2009).

WARM CLIMATE – South of Rockhampton
Before the Full Moon, silver beet, nasturtium and sunflower can be sown directly into beds, as well as a green manure crop of adzuki bean, cow pea, lablab, mung bean, pigeon pea, soybean, Japanese millet, millet, or sorghum.
During First Quarter phase, bush and climbing beans, eggplant and pumpkin can be sown directly into beds, and capsicum, rock melon, summer squash, tomato, watermelon and zucchini can be sown or planted out.
During Full Moon phase, beetroot, carrot, parsnip, radish, and watercress can be sown directly into beds. Banana passionfruit, lemongrass, passionfruit and dandelion can be sown or planted out, and banana, mango, pineapple and mint can be planted. Cuttings of mint, oregano, rosemary, sage, thyme, and watercress can be taken.

WARM CLIMATE – Rockhampton northwards
Before the Full Moon, sow a green manure crop of adzuki bean, cowpea, lablab, mung bean, pigeon pea, soybean, Japanese millet, or sorghum.
During First Quarter phase, capsicum, tomato and watermelon can be sown or planted out.
During Full Moon phase, lemon grass can be sown or planted out, and mango planted.

TEMPERATE CLIMATE
Before the Full Moon, cabbage, lettuce, silver beet, dill, nasturtium and sunflower can be sown directly into beds. Leek and spring onions can be sown as well as a green manure crop of adzuki bean, cowpea, mung bean, pigeon pea, soybean, millet, Japanese millet, or sorghum.
During First Quarter phase, bush and climbing beans and sweet corn can be sown directly into beds. Capsicum, cauliflower, cucumber, eggplant, rock melon, summer squash, tomato, watermelon and zucchini can be sown or planted out.
During Full Moon phase, beetroot, carrot, parsnip, and radish can be sown directly into beds. Banana passionfruit, passionfruit, dandelion, lemon grass and watercress can be sown or planted. Banana, mango, pineapple and mint can be planted. Cuttings of marjoram, mint, oregano, rosemary, sage, thyme, and watercress can be taken.

COOL CLIMATE
Before the Full Moon, cabbage, grain crops, lettuce, silver beet, tatsoi, dill, and sunflower can be sown directly into beds, as well as a green manure crop of adzuki bean, mung bean, soybean, cereal rye, millet, Japanese millet, or sorghum. Broccoli, Brussels sprouts, leek, lettuce, spring onions, sweet basil and parsley, can be sown or planted our. In warmer areas, NZ spinach and nasturtium can be sown directly into beds, and in colder areas bulb fennel, open-headed Chinese cabbage, and mizuna can be sown directly into beds.
During First Quarter phase, bush and climbing beans and sweet corn can be sown directly into beds, as well as suitable varieties of pumpkin, rockmelon and watermelon (see notes at beginning of post). Cauliflower, cucumber and zucchini can be sown or planted out, as well as summer squash in warmer areas only.
During Full Moon phase, beetroot, carrot, parsnip, and radish can be sown directly into beds. Dandelion, pyrethrum, sage, and watercress can be sown or planted out, and mint planted. Cuttings of rosemary, thyme, and watercress can be taken.

Bromeliads are an interesting group of plants with over 800 varieties. Some bromeliads are epiphytic (grow on trees or other objects for support) while some require soil for their roots – including the most well-known member of the family – the pineapple plant (Ananas comosus). Bromeliads are very easy to grow in warm and temperate climates, and have an amazing range of foliage and flower shapes and colours. Most bromeliads grow in a rosette form with a central well, and their unusual flowers grow from the central well.

The blade leaves of bromeliads funnel a lot of water into the central well, providing moisture for insects and other small creatures in times of drought, and the insects provide organic matter to fertilise the plants. This regular supply of food and water also attracts frogs.

If you like having frogs in your garden, try growing some bromeliad genera with soft, leathery, broad leaves – for example Aechmea, Neoregalia, Vriesea or Bilbergia, which grow best in part shade around the base of trees. These bromeliads rely mostly on their central well for water and food, and use soil mainly for support. The rosette of leaves also provides a hiding place for frogs.
Plant in autumn in warmer areas or spring where winters are cold. Grey-leaved bromeliads absorb moisture from the atmosphere and do not need soil, and bromeliads with heavily barbed leaves do best in acidic soil in full sun.

Organic gardeners use untreated open-pollinated seed. Open-pollinated seed varieties are selected for consistent vigour, nutrient levels and flavour. You can save mature seeds from these varieties because they reproduce true to type. The benefit of saving seed from your own crops is that the seed will have come from plants that have adapted to your local growing conditions.

Sometimes you will see ‘F1′ after the name of a seed variety. This is hybrid seed where two parent plants have been self-pollinated under controlled conditions for up to 10 generations before the parents are cross-pollinated to produce their first filial (offspring) seed – known as F1 seed. So-called hybrid vigour only exists for one generation, as seed collected from plants grown from hybrid seed is either sterile or reverts to the characteristics of one parent. Consequently, it is not worthwhile trying to save seed from hybrid plants.

You can find more about different types of seed, including GM seed, in my book Easy organic Gardening and Moon Planting, pp 138–140.

Open-pollinated vegetable, herb, flowering annual and green manure seeds are available from a range of suppliers, including those listed below. Seed packets are approximately $3.00-$3.80 each. Seeds from some suppliers can be purchased at retail outlets and some have on-line catalogues for easy browsing. The eastern mainland states of Australia can order seed by mail from other states if there are no local suppliers, but Tasmania and Western Australia have restrictions on some species of seed. Suppliers for Tasmania and Western Australia are listed separately.

Eden Seeds (Qld) – www.edenseeds.com.au
A wide range including bulk seed and green manure mixes (inoculants included if available). Seed is also available from some retail nurseries.
Eden Seeds also have a certified organic range of seed (some imported) at – www.selectorganic.com.au
Eden Seeds and Select Organic Ph/Fax: (07) 5533 1108

Green Harvest Organic Gardening Supplies (Qld) – www.greenharvest.com.au
A wide range including green manure mixes (inoculants included), and organic gardening products.
Ph: (07) 5435 2699 email: inquiries@greenharvest.com.au

Greenpatch Organic Seeds (NSW) – www.greenpatchseeds.com.au
A wide range including bulk seed and a green manure mix. Seed is also available from some retail nurseries.
Ph: (02) 6551 4240 email: enquiries@greenpatchseeds.com.au

Mr Fothergills Seeds (NSW) – http://mrfothergills-seeds-bulbs.com.au
A limited range of certified organic seed, but mostly hybrid seed.
Available from some retail nurseries.
Ph: (02) 45775457 e-mail: sales@fothergills.com.au.

Diggers Seeds (Vic) – www.diggers.com.au
A limited range of certified organic seed, but mostly open-pollinated seed and some hybrid seed. Seeds are cheaper for members of Diggers Club.
Ph: 03 5987 1877 email: info@diggers.com.au

The Seed Savers Network www.seedsavers.net
This network saves and shares open-pollinated seeds. Phone/fax: 02 66856624

Cornucopia Seeds (Vic) www.cornucopiaseeds.com.au
Open-pollinated and heirloom seed, and organic gardening supplies.
Ph: (03) 5457 1230 Send email from web site.

Tasmania

Phoenix Seeds
Open-pollinated vegetable, herb and flower seed, and some hybrid seed.
Voice mail: (03) 6267 9663 email: phnxseed@ozemail.com.au

Four Seasons Herbs – www.fourseasonherbs.com.au/shop/
Organically grown open-pollinated vegetable and herb seed.
Ph: 0412 721 268 email: sales@fourseasonsherbs.com.au

Western Australia

Bay Seed Garden
Organic seed producers of non-hybrid and heritage vegetable, herb and flower seed. List available – send 1x55c stamp.
Ph: (08) 9752 2513 Mail: PO Box 1164 Busselton WA 6280

The Greenhouse – www.thegreenhouseorganic.com
Organic vegetable and herb seed. Seed is also available from some retail outlets.
Ph: 0400 239 258 email: sales@thegreenhouseorganic.com.au

Eden Seeds (Qld) – www.edenseeds.com.au
Has green manure mixes (inoculants included if available) that can be shipped to WA.
Eden Seeds Ph/Fax: (07) 5533 1108

Soil has been slow to warm in many parts of Australia during October. Planting will have to be adjusted to suit local microclimates rather than a general climate zone. Advice to sow sweet corn in Warm climates this month will apply only to those areas that do not have almost continual rain in January. Pollination of corn is poor in wet weather, and the crop could be lost. However, corn of any variety can be sown as a green manure crop, though, because green manure plants are cut down when about knee high.
The following gardening advice is an abbreviated list for vegetables, fruit trees and some culinary herbs that can be planted during November in Australia and New Zealand. A comprehensive guide that includes planting times for the entire garden, as well as when to fertilise, prune, take cuttings or divide plants, can be found in my book Easy Organic Gardening and Moon Planting (Scribe Publications, 2009).

WARM CLIMATE – South of Rockhampton
Before the Full Moon, cabbage, suitable lettuce, silver beet, NZ spinach, nasturtium and sunflower can be sown directly into beds, as well as well as a green manure crop of adzuki bean, cowpea, lablab, pigeon pea, soy bean or millet, Japanese millet, mung bean or sorghum. Parsley, spring onions and sweet and purple basil can be sown or planted out.
During First Quarter phase, bush and climbing beans, eggplant and sweet corn can be sown directly into beds, and pumpkin, rockmelon, summer squash, tomato, watermelon and zucchini can be sown or planted out.
During Full Moon phase, beetroot, carrot, radish and sweet potato can be sown directly into beds, and banana passionfruit, passionfruit, pawpaw, pineapple, lemongrass and watercress can be sown or planted. Banana suckers can be planted.

WARM CLIMATE – Rockhampton northwards
Sow a green manure crop of adzuki bean, cowpea, lablab, pigeon pea, soybean or millet.
During First Quarter phase, sweet corn can be sown directly into beds, and capsicum, eggplant, tomato and watermelon can be sown or planted out.
During Full Moon phase, radish and sweet potato can be sown directly into beds. Banana, passionfruit, pawpaw, pineapple, and lemongrass can be sown or planted.

TEMPERATE CLIMATE
Before the Full Moon, cabbage, grain crops, lettuce, rocket, silver beet, NZ spinach, dill, nasturtium and sunflower can be sown directly into beds, as well as a green manure crop of cowpea, mung bean, pigeon pea, soybean, millet, Japanese millet, or sorghum. Leek, spring onions, basil and parsley can be sown or planted out.
During First Quarter phase, bush and climbing beans and sweet corn can be sown directly into beds, and capsicum, cucumber, eggplant, pumpkin, rockmelon, rosella, summer squash, tomato, watermelon and zucchini can be sown or planted out.
During Full Moon phase, beetroot, carrot, potato, radish and sweet potato can be sown directly into beds, and banana passionfruit, passionfruit, pawpaw, and watercress can be sown or planted out. Asparagus seedlings, banana suckers, mango, pawpaw, mint and lemongrass can be planted.

COOL CLIMATE
Before the Full Moon, cabbage, headed and open Chinese cabbage, bulb fennel, grain crops, mizuna, rocket, silver beet, NZ spinach, tatsoi, dill, nasturtium and sunflower can be sown directly into beds, as well as a green manure crop of mung bean, soybean, barley, cereal rye, millet or Japanese millet. Brussels sprouts, cabbage, celery, leek, lettuce, parsley, silverbeet, spring onions and chamomile can be sown or planted out.
During First Quarter phase, bush and climbing beans and sweet corn can be sown directly into beds, and cauliflower, cucumber, suitable pumpkin and rockmelon varieties, summer squash, tomato, watermelon and zucchini can be sown. In warmer areas, capsicum and eggplant can also be sown. In colder areas, sow suitable broccoli varieties.
During Full Moon phase, beetroot, carrot and radish can be sown directly into beds. Asparagus seed, chives, oregano, pyrethrum, rosemary, sage, thyme and watercress can be sown or planted out. Blueberry, cherry guava, mint, and evergreen shrubs, trees and vines can be planted. In colder areas, parsnip and lawn seed can be sown.

I’ve had several e-mails recently from gardeners who have used purchased soil or organic fertilisers and found that their plants were sickly or not growing because they were growing in soil that is too alkaline.
Soil pH (acidity or alkalinity of soil) is extremely important because determines which nutrients are available to plants. All the major nutrients are only freely available to plants within a narrow soil pH range of 6.5 to 7.5, where essential trace elements are also available, and aluminium is locked out.
See What’s soil pH?

Lime should only be added to soil where testing of soil pH shows a need for it. Mushroom compost and poultry manure (including dynamic lifter) can be quite alkaline, and some suppliers are now adding lime to bagged cow manure and horse manure because some customers objected to the smell, (usually caused by nurseries leaving bags sitting in hot sun). And, only agricultural lime (calcium carbonate) should be used when liming is necessary as hydrated lime can burn plant roots and reduces nitrogen levels through conversion to ammonia.
When purchasing soil, always check the pH before adding fertilisers or lime to it, and always test the pH of your compost before adding it to the garden (well-made compost has a pH of around 6.0-6.5). If soil pH is not higher than 8, you can reduce the pH using elemental sulphur (according to the instructions on the pH kit) and dig into topsoil a 5cm layer of well-made compost, which will buffer plant roots from the unsuitable pH. Or, grow a legume as a green manure while waiting for the pH to reduce. Slash the legumes as they start to flower and dig them into the top 10 cm of soil. See Soil pH too high? , also Changing soil pH.

If the pH is higher than 8, it is not easy to reduce it with sulphur alone. As organic matter breaks down in soil it releases hydrogen ions that will replace the calcium ions in the soil, and gradually reduce the pH. Cow, horse or sheep manure (but not poultry manure) under mulch will also reduce the soil pH gradually as it breaks down. However, be very cautious where you source manures and mulch as more farmers are using herbicides that remain active in manures and mulch materials (except lucerne and pea straw) until they are broken down by soil bacteria. Test soil every 6 weeks after digging in the green manure, and you can use it for general vege growing when it gets below 7.5.

If you are in the Taree area this Sunday (23rd October, 2011), Greenpatch Organic Seeds are having an open day from 10:00 am to 3:00 pm. Activities include a tour of the farm, garden and nursery; demonstrations on saving particular types of seed, and a seed-saving workshop for home gardeners so that you can learn how to save viable seed from your own backyard crops.
Members will receive a 10% discount on purchases.

For directions to Greenpatch, email: enquiries@greenpatchseeds.com.au – or phone 02 6551 4240