Just pertaining to the species orchid question, an old but good source are the Baker culture sheets: Orchid Culture -- Charles and Margaret Baker
I don't have Orchid Wiz, but I have heard the Baker sheets may be incorporated into that database.

You certainly can use them outdoors, and I have been considering that, considering I would use the solution for my orchids, bedding plants, fruits, vegetables, and herbs. They aren’t cheap, so getting one to fertigate a small number of orchids simply may not be worth it. The particular sprayer I have has a 1-quart feed tank and can be adjusted to a large range of dilution rates. I typically use 1 oz/gal, meaning the tank can have 32 gallons of capacity. Then I just add the proper amount of powder to make each gallon dispensed be at 100 ppm N, when diluted one ounce per gallon, fill it with water and go.

In my opinion, while the dilute/frequent scheme is likely the best, it is certainly not the only way to feed. Personally, I try to avoid going longer than a week or maybe two, between feedings, but monthly is not unheard of. I suspect that the plant will get more fertilizer if fed 4 times a week @ 25 ppm N than if fed once a week @ 100 ppm N and just watered 3 other times, but is that a significant difference in such slow-growing plants? I try to never let my plants dry out. I water heavily until water is rapidly draining out of the pot. Google is your friend! Read everything you can get your hands on, in print and online.Sure. Why not?

I found that a 2 gal pump sprayer was completely adequate for quite a few orchids... before I bought my house, when I first got into orchids, I lived in a condo and the spare bedroom became my "greenhouse" http://orchidcentral.org/GrowingAreas/indoor.jpg .
I just watered these until the water ran out of the pot. The bins under the plants caught the water. its evaporatuin raised the humidity a bit. I only had to clean out the bins every 6 months or so when the algae got too ugly.

Wow that setup looks awesome! Well for my orchids in wood chips, water starts flowing through in just a few moments. Do I wait until it's at maximum flow, no longer increasing? That's my theory haha.

So do you treat a plant in moss any differently? I imagine you would water less often. Though, would it be okay to use the same concentration as with orchid bark?

So can you water too much at once, in a single watering; can that burn the roots? Either with low concentration, or higher?

:thanx:

Considering you’re flushing the medium at the same time, I think your “theory” is valid.

In my opinion, the same principles apply, but keep in mind that heavy, top-down watering of sphagnum will compress it, so it will need to be replaced more often.

As far as the concentration question is concerned, I think you need to consider “exposure time” in your thinking.

Roots can only absorb solutions while in direct contact with them. For a vanda grown bare root in a basket, that occurs only when the plant is watered. For a plant in coarse bark, it is longer, because the saturated bark can still deliver some solution to the roots in contact with it for a bit. In sphagnum, the root contact area is greater and it holds liquids longer. Semi-hydro culture provides constant contact, but less contact area, due to the coarse medium.

Try the analogy of a shower, where the hot water component is the “fertilizer” - no matter what “dilution” factor (that is, cold to hot), and no matter how long you’re in the shower, your exposure is constant, and once you turn off the water and you dry off, the exposure ends until the next shower.

During your exposure to the shower, your skin has had an opportunity to absorb some water, and the longer you’re exposed, the more that will be.

We know that velamen is like a sponge, trapping solutions for the plant to take up at its own pace, but we don’t really know how rapidly the liquid is actually taken into the vascular system from the velamen. Here, I think the shower analogy applies again - if warm (dilute), you can stay in it all day, but if hot (concentrated), you’ll get burned almost immediately.

Orchidwiz includes more than 4700 Baker sheets (the entire opus, including some that were scanned from hard copy). It's my go-to source along with orchidspecies.com . Together, I end up with an encyclopedia of species information.

If you want a magnificent set of books stuffed with species info and photos on the smaller species, consider A Compendium of Miniature Orchid Species by Mary E. Gerritsen and Ron Parsons

Thanks for the recommendations! I forgot to ask a basic question. With the dilute fertilizer with every watering, I am adding 1/8 tsp per gallon for 50 ppm, of Miracle Gro Orchid Food. Is it okay to use a very heaping spoonful?? ;)

And if that's okay, can I mash it down and heap it more?! :)

It's like cooking, or performing chemistry. Use a level measuring spoonful. Level it with a butter knife if you can't get it even on the opening to the container. Don't mash it down.

If you use a heaping spoonful or mash it down you will make a higher concentration of solution than you want.

More is not better. Think of the nitrogen content as “calories” in your own diet: too few and you won’t be strong enough, the correct amount and you’ll be healthy, and with excess, you’ll become fat, flabby, and disease prone.

As an aside, when the Northeast Georgia Orchid Society closed it's doors (not enough people left in the club that could help run things :( ), we took the remaining treasury, and donated it to the State Botanical Garden of Georgia, specifically so they could purchase OrchidWiz.