Archive | January, 2011

Powdery Mildew

22 Jan
A common complaint that I’ve seen on various forums is white powdery mildew. It can affect a wide variety of plants including grapes, strawberries etc but the questions mostly enquire about their squash’s and melons. Indeed my zuchinni, cucumber and rockmelon (cantaloupe) plants all have this condition which is what started this research topic.

Zuchinni with powdery mildew
While it’s commonly referred to as white powdery mildew is can come in white, brown or grey. It’s caused by a few different types of fungus all from the Erisyphales order  for those botanically minded folk. It seems that specifically my garden has Podosphaera fusca which according to Wikipedia affect curbits (cucumbers, squash, melons etc). The picture on the left show’s prominent vibrant mildew clusters.

Powdery mildew is primarily caused by environmental conditions such as high humidity, not enough sun etc. If possible try and get the affected plants 6 hours of good solid sunlight a day. Saying that though it hasn’t helped my rockmelon which get’s full sun all day.

Other treatments that I have found are your usual supects of fungicide and store bought chemicals which I’m not a fan. An organic treatment that I am using and it looks to be working is milk. Good old fashion cows milk has natural anti-bacterial agents called lactoferrin. Lucky for us these agents aren’t detroyed when milk is pasteurized.

To spruke some of the antibacterial benefits, lactorferrin is produced commerically as an over the counter supplement for athlete’s foot, yeast infections and for athlete’s to boost their own immune systems while training. Lactoferrin is in highest concentrations in human breast milk but also in small quantities in cows milk and, would you believe it, tears and nasal secretion.

Zuchinni with powdery mildew
after a milk spray.
I haven’t tried sneezing or crying on my plants but I have sprayed them with the recommended 1 part milk, 9 parts water a few times with ongoing success. If you use skim milk there’ll be less fat in it to go rancid but I haven’t had a problem with this. Make sure you spray under the leaves as well as the fungus is on both sides. Compare the picture to the right with the one above. You can see the fungus is less distinct and starting to fade. This is 2 weeks after the initial spray with a follow up spray a week later.
Zuchinni new growth after
2 weeks spray and cut back.
I trim back the badly damaged leaves before spraying. This will allow the plant to spend it’s energy on the parts that are savable. New growth should bounce back once the fungus isn’t sapping the energy from the plant.
Zuchinni new growth after
2 weeks spray and cut back.
Other organic solutions for powdery mildew that I’ve seen but not used include:
  • Sodium Bi-carb – up to 10g in 1litre of water. Carefull though as too much will burn the plant.
  • Liquid Seaweed – a great fertilizer which will help the plant fend off attacks but sometimes too much fertilizer can cause the powdery mildew in the first place.

Have you tried milk or any of the other solutions? Have you any other ideas? Would love to hear about your stories battling this very common problem.

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What’s in a trellis.

10 Jan
I recently borrowed some seeds from a fellow gardening freind, Andy. Among them were purple beans, peas, corn and butterlead lettuce. All have sprouted nicely in my seed raiser but I was stuck with how I was going to grow the climbing beans and peas. I had an option to ask the neighbours if I can run them up the shared fence but I was concerned that all the beans would grow on their sun filled side of the fence. So I decided to build a trellis.

From the ancient Indo-European word “trejes” the word trellis is related to the english word “three”, “trio”, & “tripod” as well as non-english words for three such as tri, drie etc. Trellis actually means something made of “three threads” though these days trellis’ come in all sort of shapes and sizes.

And to keep the three theme I decided to plant my new seeds in the “three sisters” approach. This is a native american style of growing the three staples, beans, maize and squash (though i’m using rockmelon). These three plants form a symbiotic relationship in that the maize provides something for the beans to grow up removing the need for poles. The beans lock the nitrogen in the soil helping all plants. Finally the squash provide a ground cover or natural living mulch to keep the weeds away.

Below are the various styles I found while looking for solutions (my graphic design skills were severly tested!)

Firstly, the traditional 3 pole teepee style (left). This consists of three bamboo poles lashed together at the top and thread (twine, wire etc) run betwen the legs. The lashing on the top doesn’t have to be fancy, it just needs to be solid. A downside to this style is that if you have very bushy plant growing you will struggle to get at the beans on the interior.

Next is the 4 pole teepee style (right). Similar to the 3 pole variation but you can leave one side free of threads allowing you (or the kids / pets) access to the interior to play, pick the interior beans, get out of the sun etc.


The next variation is a little trickier but scales well for large plants or gardens. It’s known as the A Frame. If the poles are tall enough it’s conceivable you could get inside but but the main benefit is that you need more space you just build another A and run beam across the top.

Finally the simplest solution and the one I used is the straight up and down. 3 or more poles hammered into the ground and string run between the legs. This isn’t very stable so the legs need to be hammered in deep. I’ll see how this goes and

report back.

With all the styles plant the seedings around the base of the poles. You might need to loosely tie them to train them towards the string but after that they should find their own way.

Have you built your own trellis? What style? If you have any tips please send them through. Love to hear what worked and what didn’t.

Growing Passionfruit.

6 Jan
Image from Wikipedia

I’ve always loved passionfruit. There’s something about getting a cold spoon dug into the centre of a passionfruit, grating it up the side to get all the seeds and savouring the chunky sweetness. So with my garden going well and my understanding that passionfruit vine can be planted all year round I thought I’d give it a go. I’m going to put them in my garden as well “strategic” places around the neighborhood. 🙂

The passionfruit is the fruit from the passiflora vine. There are over 500 types of passiflora and while not all varieties produce edible fruit their spectacular and diverse flowers have been sort after throughout the ages, partly because for most varities the flowers only last a single day!!

In Australia we tend to get the passiflora edulis, P. Edulis, variety, specifically the Black Magic variety. P. Edulis come in two colors, purple originating in Brazil, and yellow, also known as the tropical passionfruit with an unknown origin.

Passiflora vines a very fast growing so need alot of nutrients. In the old days the plants were planted with a liver or ox heart in the soil to provide lots of iron and other nutrients. The vine will climb over anything near by so many gardeners will train it up a trellis or fence. For best results train the vine to the top of the fence / trellis first and allow it expand out. P. Edulis can grow 4.5m – 6m per year and will live for about 5 – 7 years. Give it a major trim every 2 years and overall keep it thin else it may develop bacteria and fungal problems.

In Australia expect a crop between July and November and then again in Feb to April. Though I’ve read in environments it will fruit all year round. This is the kicker for me, a good healthy vine will take 12 to 18 months to fruit! Grrrr, so my seedlings have a while to go.

The fruit is very high in beta-caratone, potassium and dietry fibre. Let the fruit go a bit wrinkly before you eat it as this allows the sugars to condense and provide a stronger flavour. My mother-in-law says you can freeze the passionfruit whole until you want to it use. Let me know if you’ve done this.

The flower has alot of history. In various countries it’s known as Christ’s Thorn (Spain), Christ’s Crown and Christs Boquet (Germany). What’s all this reference to Christ I hear you say? Well, the catholic missionaries saw many religious connections to the flower. An extract from this Wikipedia article helps explain the connection:

  • The three stigmas were to reflect the three nails in Jesus‘s hands and feet.
  • The threads of the passion flower were believed to be a symbol of the Crown of Thorns.
  • The vine’s tendrils were likened to the whips.
  • The five anthers represented the five wounds.
    Image from Wikipedia

    

  • The ten petals and sepals regarded to resemble the Apostles (excluding Judas and Peter).

A few other uses for the plant:

  • It’s suggested that it has antidepressent properties however most of these compounds are in the leaves. This might explain why some cultures smoke the leaves.
  • Both the fruit and leaves are said to lower blood pressure.
  • In Mexico the fruit is eaten with chilli and lime. I’m very keen to try this combination. Sounds a treat.

Finally, to harvest the seeds (as I did from a store bought fruit), simply open it up, put the seeds in your mouth and suck the pulp off, wash them off and plant them in a seed raiser. 

I apologies for the images from wikipedia. I’ll update them with my own once my plants start growing.