Water First Rule
 

I am concerned with the "Water First Rule". Piggy-Back from previous post on "Fertilizing".
Watering 1-2 days before would seem better than doing as I do and water the same day or just before spraying. However, in my orchid house the HAF is adequate to dry at least the plant surfaces out in a matter of hours, and in northern Florida the plants outside (particularly the hanging plants) are dry equally fast. Thus I tend to water just before spraying. "Water First" seemed more appropriate to when I use to fertilize plants in bark infrequently at full strength, than now when I fertilize every watering at 1/4 - 1/2 strength + Dial dish soap.
The only exception to this might be the Phalos that are in sphagnum. If I wait too long to water them, then the sphagnum gets a bit crisp (at least the top couple of inches). Then I might be able to understand watering the plants to get the sphagnum hydrated and more receptive to accepting or exchanging rather than channeling the incoming solution.
The idea that the velamen can only accept just so much liquid rings true, but even then there will be transfer from an area of greater concentration (fertilizer solution) to the area of lesser concentration (water wet velamen) so some fertilizer ions will make it to destination. Will it be enough fore instance to supply that 100-150 ppm nitrogen to the plant that many of us shoot at? Intuitively I think not, but I sure wish someone would chime in on the "Water First Rule" related to 1) fertilizers, 2) systemic insecticides and fungicides, 3) topical insecticides and fungicides. Watering before spraying seems to be a hand-me-down rule from the "old days" of osmunda and bark i.e. organic substrates. How does it apply to modern technology of Perlite, LECA, Epi-Web etc, and fertilizing at every watering with 1/4 to 1/2 strength fertilizer solutions?
I'm already regulating the pH (5.8 - 6.2) of spray solutions for both fertilizers and pesticides based on input about activity levels of active ingredients relative to pH.

While I'm asking questions! One more. I read some place that some vital nutrient components are "best" or "only" taken up by the plant "under the leaves" and at the "new growth tips" of roots. S/H has the velamen and root tip covered, but what about "under the leaves" or on top the leaves for that matter, since I can't remember the quote exactly? I currently add surfactants to fertilizer solutions as stickers based on "old school" foliar fertilizer rules.

Anyone out there care to comment on these questions please.

I believe the "water first" rule was established back when feeding was done very infrequently, but at high concentrations, and it was a way to prevent chemical damage ("burning") to the roots. I recall a large facility feeding catts at about 500 ppm N, about monthly. Under those conditions, I guess the actual absorption may have been adequate.

Feeding at the 100-150 ppm N rate at every watering seems far more appropriate to me. All of that is independent of the medium, although some ingredients may need to be flushed more often than others.

Alan Koch of Gold Country Orchids is the big proponent of underside foliar feeding. I suppose the fact that there are more stomata under many orchid leaves than on top - a water loss reduction mechanism - makes that a logical assumption, but I doubt it's a significant pathway of absorption. Think about it: if you spray the underside of the leaves, doesn't most of the solution go down into the medium where there are roots specifically designed to absorb stuff?

Maybe if you have a rootless plant and are trying to revive it the leaf stomata become significant absorption sites, but I can't see that as a primary route in a healthy plant.

A lot depends on the plant, too. (I'm talking way out of my league here, so bear with me, but I believe I have the concept correct) Crassulacean acid metabolism (CAM) plants like phals tend to have very waxy leaves with few stomata, and those are only open at night when temperatures tend to drop, forcing relative humidity higher - again, water retention mechanisms. Any foliar feeding is basically insignificant in them. In others, it may be better, but I still think it's a minor contributor.

I don't water first usually when not bone dry tho . Here is a link with some info .for those of us that are CAM. challenged . :) Gin
Plant Biology & Botany 2007 - Abstract Search

Dial soap in the fertilizer? I "think" I understand the theory, but would like to hear more. Could someone in the know explain further? Everyday is a learning experience! Thanks, Gladys

Not sure about the soap , I have read it breaks the surface of new bark , also bugs don't like it , fungus knats ect . It acts as a sticker when used with bug sprays .. I am curious too as to why in Fert. .... Gin

if the plants are really dry can water first. We normally
fertilize plants when they are wet by rains.

For my two cents....

Dr. Martin Motes regularly mentions in his monthly articles that watering first isn't a good idea for our conditions. For South Florida, the growing season is long and hard--plants require plenty of energy to get the job done. I haven't watered first for years--mostly because I don't have time, and I've been very satisfied with the results. I don't see any signs of damage.

As for the soap, yes, I use Ivory dish soap in just about everything I spray...fert, Ortho, Cleary's. Not only does it act as a surffectant, it has it's own merits as a topical remedy for mites, etc. As a bonus, it smells better than the chemical alone.

I agree with Rhonda,
I have always used "mild" dishsoap and at time Murphy's oil soap as an alternative to harsh and deadly chemicals.
Its seems to be an organic alternative like neem oil.
It also works as a sticker spreader when you want what you are applying to stay put instead of washing off, which is the reason it is is such a good sufficant against pests.

In the discussion about dish soap, how much would you put in a gallon of foliar feeding solution?

Julie