I've had a terrible time here in L.A.- zone 10- with powdery mildew - this time it got my squash, cucumbers, tomatoes and bush beans; now it's working on my pumpkins. I have tried a bunch of things - milk, baking soda and a little detergent, etc.- but they seem not to work. Realize I probably water too late in the day and put manure on at the wrong time...but still! Most sites states that "treating the soil" is not useful, but one site says to cover with clear plastic and let it sit for 4-6 weeks - longer if it's rainy. Seems like a long time to wait - but I'd do anything to fix this problem! Can anyone help? Another thing - I'm from the South and can't help but notice how much better plants like melons, okra, summer squashes do there. I'd attribute this to it nearly always dropping down to the 50's and 60's at night, instead of staying hot. Am I the only one that thinks this?

This got really long way too fast, and I did not even get to tell about my new Cycnoches chlorchilon! Oops! I did! It has just got a nubbins of a spike, and I think my rather confused Rhynchostylis gigantea is putting up a spike too. Very exciting times here in the north! I did a little bit more reading too on line and much of the text espousing the wonders of H2O2 is from the hydroponic and aeroponic growers. I have given this some additional thought and have hit upon a theory of sorts. And more questions. A funny side note, many of the indoor growers that are using some very hi-tech and sophisticated systems and nutrient solutions are not growing Orchids, or fruits or veggies for consumption, but in fact are growing vegetable matter for combustion. It strikes me as funny that in my youth the persons most likely to indulge in this recreation were that last ones you might suspect as having the mental horsepower to put together these kinds of growing systems. Do not even ask about the plant genetics discussed in some forums, and one site had what looked to be a doctoral dissertation on the molecular biology of a very particular part of the plant, more specifically on the plants production of the compound that makes this plant an item of interest in the first place. I was fascinated and humbled, but will continue to grow orchids. As a final humorous note, several of my sons friends (college age) have seen my grow lights and set up and suggested that the orchids are just a cover for growing this particular "other" indoor crop. I digress. Howard, the resources I saw suggest using only the 35% food grade H2O2, and diluting it to around 1%, and then using this 1% solution anywhere from 1 to several tsp per gallon of water. A ratio of 1 part 35% H2O2 to 11 parts water is alleged to yield about a 1% solution, but I have not checked the math on that. The reason for using the 35% food grade is that the typical 3% stuff from the market of pharmacy has several compounds added as stabilizers to prevent degradation of the H2O2 during storage that may theoretically reduce the availability of the H2O2 and may be outright bad for the plants. Modest quantities of food grade H2O2 are cheap, but make no mistake undiluted 35% H2O2 is a liquid to be treated with reverence. Since this amount of a 1% solution added to a gallon of water makes a pretty thin soup it is not hard to see how undiluted 3% might be very hard (or deadly) on plant roots. I am betting the cuticle on leaves offers some margin of safety when 3% or less is applied to a crown or diseased plant tissue topside. My speculation(s): The growing conditions the roots of hydroponically grown plants are in very different conditions than plants in soil, bark or other media. Semi hydro as it is often called is not really the same situation either as I see it. The hydro people are also using higher concentrations of H2O2 as washes to keep tanks hygienic, and some sites suggested that having low concentrations in the re-circulating solution might prolong its safe use by reducing the rate of growth of plant pathogens. The roots of plants grown in soil or soil-less media have the potential for exposure to both helpful and harmful microorganisms. One bit of sand in the Vaseline for me is that H2O2 is as noted previously just a dumb bomb, killing in general as opposed to killing only the harmful organisms. In this light it could be helping on one hand but disturbing the balance of important microflora in the immediate root environment. So, if the benefit is in cleaning up the bad stuff (plant pathogens = bad stuff) at the root, it may give not a net gain if it is also killing off the good stuff too. Now bear with me here, I am not being argumentative, that would be my 16 year old daughter, I am just thinking out loud and asking some questions. The secondary hypothesis is that the release of oxygen near the root is itself helpful to the plant directly. What I am wondering is how the oxygen near the root is helpful to the plant? Roots are not primarily respiratory organs in most plants. Roots are important for absorption and transport of water and micronutrients, anchoring of the stem to the substrate, in some cases the storage of "food", and in more specialized cases active energy production through photosynthesis. We are for the time ignoring the "Ghost" orchid. In a non-photosynthetic root one could wonder what need it might have for oxygen at all. Why then do we consider oxygen to be good to have around the roots? Also the role oxygen plays in plant physiology and "respiration" is quite different than how we think of oxygen and our breathing. In truth on a quantum level it could be argued that there is little difference in its function, but you would really be splitting hairs there. Plants both use oxygen and generate it as a byproduct. We think of them as "making" oxygen because at the end of the day the plant has made more oxygen than they have used while living. Food for thought is all, just food for thought. PS: Urea has a little nitrogen in it too, though it may not be the most available form to the plants.

OK, wattleblossom - your garden sounds absolutely spectacular, but there are several points I'd like to make: 1. 'Your mileage may vary' : many of the species you have successfully grown, be they from Oz or wherever, simply wont do well in large parts of Queensland/Northern NSW/NT. Thats commonsense, but its easy for new gardeners to get drawn into the images presented by the (south-dominated) gardening media. Its a tribute to you that you have found the plants that thrive in your area. 2. Both sets of plants will be as 'low maintenance' as you want them to be, and that comes down to your preferred presentation. For example, pruning is a must for many shrubs, but how many need to be topiarised ? We can create hedges with exotic conifers or a species such as Melaleuca, but how can we prevent dieback in the centre of our new hedge ? This is one area where an informal planting scheme wins hands down, at least IMO. 3. From your description, it seems that you have two clearly delineated areas, and plants belong in one or the other by courtesy of their origin. I accept that this works for you, but have to ask if we need to build such arbitrary boundaries. I've made the point several times that I believe many of our rainforest plants are good companion plants for Vireya Rhododendrons, Gardenias and similar glossy-leaved exotics, and mixing dry climate plants from similar latitudes is already a well-worn path. Proteas are a slightly different story, although my 'high NPK' experiment still hasnt killed my tropical grevilleas :) 4. I also struggle with the insect-attack issue : none of us likes to see their evil handiwork, but I've been very lucky to date. Grasshoppers and caterpillars currently seem to be be enjoying exotics and natives alike in my garden, but its also rewarding to watch a magpie flying off with one of the marauding bugs protruding from its beak. Its currently very dry in CQ, and I suspect that this has pushed the insects into our gardens in larger numbers - they werent a problem in Summer. None of this makes my opinions any more valid than the next persons, but I do think that tight integration between Australian and imported plants is the key for the future of our native plants in commercial horticulture (as opposed to conservation). It will be a sad day when city kids can only see native plants in a botanical garden or arboretum. You or I could build an incredible garden using only plants from Madagascar, but would we be willing to limit ourselves to that one (admittedly sensational ..) island ? Who knows - Bunnings might start shipping truckloads of Madagascan plants after our gradens make the glossies :)

hi, once they are established they will thrive on neglect, mine get no watering at all, just rain in winter, theyre no where near any sprinklers, and fertiliser, zip, zilch, nothing :), they seem to like it that way. they should do well in a west facing position if theyre getting lots of sun. One thing I noticed with mine though, is that one of them only had a short flowering period while the other flowered all through summer, I figured it was just because they were different varieties (one is fragrant, and the other isnt), but after we removed a nearby tree to the one that only flowered a bit, it has been flowering all summer long for the first time, so the nearby trees you mentioned might be causing a bit too much root competition for them. if you want to replace them with something, the showy honey myrtle (melaleuca) make great screens and will stand up to the heat (theyll need some water for the first couple of years though), and they do grow to about the same height as the oleander.