I thought I posted this on the gardenweb forum. Now it's houzz? Had to sign up for a new user name. Anyway soo - you can get the Naked Gardener Compost or Debco Premium Potting Mix from Masters (closing soon). Course Perlite is from The Perlite & Vermiculite Factory Myaree (much cheaper than anywhere else). Sand I got from a bulk landscape place (lawn mix) but you can get 10 or 20kg bags of builders sand at Bunnings. Zeochlor is in the pool section at Bunnings. Rock Dust I got from the manufacturer direct somewhere in Bibralake (called Natural PK) but I think but you can now get a similar product from Waldecks (in Myaree at least). Waldecks also sell bentonite clay. I still want to try the gritty mix but getting my hands on all the materials has proved very difficult when I tried last year. I found a Queensland company that makes course DE (for mopping up oil/chemicals) but they didn't have a distributor in Perth. Nobody I could find has pine bark in the right size - and even if they did I'd have to by a cement mixer and modify it with a fine wire to screen it. Honestly, if an agricultural company were to produce the gritty mix and sell it in bags I think they'd make bank - even considering how long it lasts.

We have a 20' x 24' hoophouse (two layers of plastic) on decent clay soil. I am having some issues figuring out how to loosen the deeper layers of soil for planting, and how to do the final soil preparation for planting with a multi-row seeder. The first summer we did succession-plantings of buckwheat to loosen the soil and discourage the perennial weed grasses. Last summer the house grew tomatoes, herbs, peppers, chard, and brassicas. This year I would really like to implement mechanical seeding, but that requires extra care in soil preparation. I am mostly trying to follow Eliot Coleman's books on hoophouse growing--I also have the book "Teaming with Microbes" but am having some challenge figuring out how to marry up the concepts and applied them inside a structure where it never rains. Regarding loosening the deeper layers of soil, I tried using a broadfork, but cannot penetrate more than the top two inches of the soil due to mild compaction. A mattock breaks up the soil with some effort, or a Mantis tiller breaks it up well, but I'm not sure which approach is preferable. I also have not figured out how I want to water the whole hoophouse. I'd prefer not to spray water all over the wood structure, but would like to get good coverage. As a result, right now plants are spot-watered, which means that areas that are unplanted (and even areas near the plants) get very dry. So all the natural tillers (earthworms and microorganisms) have moved on. I'm thinking perhaps that maintaining a moister environment would help with the "tilling" of the deeper layers? For seedbed prep, Coleman stated that they loosen the deeper layers with a broadfork (isn't working for me), then "till" in amendments with a "Tilther," a tilling device that they had assembled using the motor of an electric drill that only tills the top 2" or so. Finished compost (presumably finely-screened) is applied over that, and the area is raked to a fine tilth, and then rolled prior to seeding. Sorry about this rambling message, but what would you suggest for: (1) loosening the deeper layers of the clayey soil to prepare for the planting? (tiller, spading, mattock, worms, green covers, or don't do it?) (2) watering system to encourage earthworms and organisms to colonize and keep the water where it needs to be? Also, is city water ok, or well water preferred?

I've used Trichoderma with good results but not with orchids. I've stopped using it solely due to cost (it's only available in agricultural quantities in Australia). A couple of things to point out: -Anecdotes regarding Trichoderma range from great to no effect so it may only be as effective as your conditons allow. I've used it on carnivorous plnts and have had good results with species that are prone to fungal problems. -Trichoderma is a soil fungi that acts by killing other fungi, so the benefit comes from an absence of pathogens rather than symbiosis. However, as a soil fungi, it's ability to prevent leaf rots is somewhat limited. Supposedly it can prevent them but don't be suprised if it doesn't. I can not find any info to suggest that it is at all discriminitive in what it kills so it may also kill beneficial soil fungi such as orchid mycorrhiza. This is of little conseqence for most commonly grown epiphytes but if you grow any terrestrials eg Cyprepedium, Calopogon etc it may do more harm than good. -It's alive so it has a limited shelflife. Refrigeration prolongs the shelflife but still I'd use it within 6 months. Factor in the preparation date to the shelflife. -It's designed to be used with conventional potting mixes and garden soils. It may not be as effective in courser bark mixes. Inorganic mixes may provide insufficient organic material to sustain the fungi for long.

I brought this thread up to thank Jim for posting an excellent article on the danger of high phosphorus: "Phosphorus carries a chemical charge that competes with other micronutrients for plant uptake. Excess amounts result in leaf chlorosis because iron, manganese, and zinc are not available to the plant. Leaf tissue turns yellow while veins stay green." http://www.rose.org/phosphorus-fallacies-too-much-of-a-good-thing/ From StrawChicago: Agree with the above, except for the quote "Commercial growers of roses for cut-flower production typically use fertilizers with a 3-1-2 NPK ratio." That applies to pots or sandy soil, but NOT for alkaline clay. Alkaline clay has more beneficial bacteria to fix nitrogen from air. I used that ratio 3-1-2 before and got a 5 feet tall own-root Scepter'd Isle, plus a giant Charles Darwin (own-root). I gave both away since they got too big & less blooms. From Wikipedia: "By volume, dry air contains 78.09% nitrogen, 20.95% oxygen." Agree 100% with the quote "Phosphorus fixates, or becomes immobile, in the soil quickly after application. This fixation is minimized at a pH level of 6.0-7.0. So all the extra phosphorus in fertilizer will become unavailable at pH levels above or below that range." With my foolish experiments of bone meal (top-dress or in the hole) ... I notice that high phosphorus induce foliage diseases, due to the suppression of zinc, a very strong anti-fungal agent. Bone meal has 24% calcium and 11% phosphorus, that's NOT as bad as higher % of phosphorus in MG-Soluble. I tested MG-Soluble before: more blooms, but more fungal diseases, plus more pests. High phosphorus induce foliage problems in my Thai basil. That hole was previously occupied by Sharifa Asma, it's right under a rain-spout, so nitrogen get leached out (10 mobility), potassium also leached out (3 mobility), but phosphorus stay put (1 mobility). I put too much Encap cow manure (high phosphorus) in that hole. Sharifa was blooming great ...6 blooms for a tiny plant (6 inch x 6 inch). But after blooming, it broke down in black spots. So I moved Sharifa out, and put a Thai Basil. Here's how Thai basil looks like, tons of blooms, but very thin foliage, with black spots, plus potassium deficiency in lower leaves. The leaves are much paler, smaller, and thinner due to zinc and iron less available.