Watering/Feeding Technique

[Ray]

Look at plants in nature:

They are fed whenever the rain flushes "crap" out of the forest canopy.

But we must realize that, as those rains are usually quite hard, there is nutrition in that cascading water only immediately after the rains begin falling. After that, it is just pure rainwater.

I have read that velamen has the unique ability to capture and trap nutrient ions from that initial "burst" and hold onto them during the subsequent downpour.

Based upon that, it seems to me that watering first saturates the velamen, preventing-, or at least slowing the absorption of ions from water applied later. That was common practise where I learned about orchids, as they were fed with a VERY concentrated solution, so that prevented "burning".

About 25 years ago or so, I started feeding a very small amount of fertilizer at every watering, probably achieving the same or better uptake than the 2-stage technique.

As far as wastefulness is concerned, is dosing with a higher fertilizer concentration after watering (when the plant will take up less of it) better than a single treatment with less fertilizer in it, but better uptake? I doubt anyone knows. However, using K-Lite at my selling price as an example, a gallon of 25 ppm N fertilizer solution costs 1.76¢, making me wonder why that would even be a concern.

[Clawhammer]

Originally Posted by Ray

Look at plants in nature:

They are fed whenever the rain flushes "crap" out of the forest canopy.

But we must realize that, as those rains are usually quite hard, there is nutrition in that cascading water only immediately after the rains begin falling. After that, it is just pure rainwater.

I have read that velamen has the unique ability to capture and trap nutrient ions from that initial "burst" and hold onto them during the subsequent downpour.

Based upon that, it seems to me that watering first saturates the velamen, preventing-, or at least slowing the absorption of ions from water applied later. That was common practise where I learned about orchids, as they were fed with a VERY concentrated solution, so that prevented "burning".

About 25 years ago or so, I started feeding a very small amount of fertilizer at every watering, probably achieving the same or better uptake than the 2-stage technique.

As far as wastefulness is concerned, is dosing with a higher fertilizer concentration after watering (when the plant will take up less of it) better than a single treatment with less fertilizer in it, but better uptake? I doubt anyone knows. However, using K-Lite at my selling price as an example, a gallon of 25 ppm N fertilizer solution costs 1.76¢, making me wonder why that would even be a concern.

Thanks Ray, I'm now pretty much convinced that fertilizing first is the better two stage technique.

In regard to the moisture that remains in a pot over the course of a few days post watering, I wonder how much is lost to evaporation versus plant consumption. Probably varies greatly by plant type and media. I think ensuring nutrient absorption on the first stage is probably the surest way to know the plant is getting access to nutrients.

To be clear, my goal would be to achieve a one stage watering regimen using my hose as that would be the best of both worlds (convenience and efficacy). Saving fertilizer and water is only a nice bonus of the two stage technique. I'm still a little weary of trusting the Chapin attachment with it's 3.7 star review and lack of sprayer options (don't love the spray nozzle design).

[Keysguy]

Good thought process there Ray, as always!

Hammer- I think you'll really like that sprayer.
I premix in a gallon jug enough fertilizer to fill the Chapin sprayer 5 times (that's how many I use). The jug dilution content is roughly equal to what would be considered a 5% fertilizer solution. I then set the Chapin at a 25% mix rate so net effect is I'm fertilizing at roughly a 1.25% effective rate. I do this weekly and really give them a good soaking. I have a fair number of vandacious plants on hangers and quite a few specimen plants. 200 orchids in total but I suspect I use a lot more fertilizer in one feeding than you would. You'll need to tinker with it to figure out what you need.

The way that Chapin works is it draws up the fertilizer from the bottom of the container and mixes at the nozzle as it's discharged until container is empty at which point it's expelling all water. Good that fert is colored so you can tell. This is unlike others like a Miracle Grow type sprayer which mixes in the container so in effect the longer you go the more diluted the concentration becomes. Kind of a useless way to do it my humble opinion.

[Clawhammer]

Originally Posted by Keysguy

Good thought process there Ray, as always!

Hammer- I think you'll really like that sprayer.
I premix in a gallon jug enough fertilizer to fill the Chapin sprayer 5 times (that's how many I use). The jug dilution content is roughly equal to what would be considered a 5% fertilizer solution. I then set the Chapin at a 25% mix rate so net effect is I'm fertilizing at roughly a 1.25% effective rate. I do this weekly and really give them a good soaking. I have a fair number of vandacious plants on hangers and quite a few specimen plants. 200 orchids in total but I suspect I use a lot more fertilizer in one feeding than you would. You'll need to tinker with it to figure out what you need.

The way that Chapin works is it draws up the fertilizer from the bottom of the container and mixes at the nozzle as it's discharged until container is empty at which point it's expelling all water. Good that fert is colored so you can tell. This is unlike others like a Miracle Grow type sprayer which mixes in the container so in effect the longer you go the more diluted the concentration becomes. Kind of a useless way to do it my humble opinion.

Your endorsement and description of the Chapin definitely is leading me in that direction. Is the nozzle adjustable at all? It looks messy for using indoors in the pics on Amazon

[Keysguy]

give me a couple hours. I'll put together a little demo video for you and post it if I can.

---------- Post added at 12:52 PM ---------- Previous post was at 12:20 PM ----------

This is the commercial version of the sprayer but they work the same way.

[DirtyCoconuts]

Happy Claps about your grow room friend...what a delightful place!!!


I am going to have to look into this Chapin sprayer as well now......thanks a lot guys!!

[thefish1337]

Originally Posted by Ray

Look at plants in nature:

They are fed whenever the rain flushes "crap" out of the forest canopy.

But we must realize that, as those rains are usually quite hard, there is nutrition in that cascading water only immediately after the rains begin falling. After that, it is just pure rainwater.

I have read that velamen has the unique ability to capture and trap nutrient ions from that initial "burst" and hold onto them during the subsequent downpour.

Based upon that, it seems to me that watering first saturates the velamen, preventing-, or at least slowing the absorption of ions from water applied later. That was common practise where I learned about orchids, as they were fed with a VERY concentrated solution, so that prevented "burning".

About 25 years ago or so, I started feeding a very small amount of fertilizer at every watering, probably achieving the same or better uptake than the 2-stage technique.

As far as wastefulness is concerned, is dosing with a higher fertilizer concentration after watering (when the plant will take up less of it) better than a single treatment with less fertilizer in it, but better uptake? I doubt anyone knows. However, using K-Lite at my selling price as an example, a gallon of 25 ppm N fertilizer solution costs 1.76¢, making me wonder why that would even be a concern.

Here is the research paper that shows what Ray is talking about. If anyone wants to read its very interesting set of experiments- the hypothesis they are testing is this:

"This study set out to test Went’s (1940) hypothesis. Using a number of orchid species in a series of experiments, we show that all prerequisites outlined above are met (fast uptake and slow loss of water, retention of both negatively and positively charged ions, and efficient uptake of nutrients into the living cortex), which lends strong support to the notion that a major function of the velamen in epiphytic Orchidaceae and other monocotyledons such
as many Araceae is to secure highly pulsed nutrient concentration peaks at the onset of rainstorms."
Aerial roots of epiphytic orchids: the velamen radicum
and its role in water and nutrient uptake

the study is not 100% conclusive but it does support the hypothesis that orchids are well equipped biologically to scavenge the first pulse of nutrients. however, I suspect that watering first doesn't really "hurt" because the roots themselves have a number of mechanisms to pull out charged ions from solution so as long as you soaked your plant sufficiently after pre-wetting I doubt it would hurt much other than waste water and time.

[DirtyCoconuts]

this echoes what i read somewhere that said you have 20-25 seconds of time for nutrient uptake and that after that it is water only and very little at that point

[SouthPark]

Nice sprayer device keysguy! The only thing for indoor usage is to really ensure the hose and connectors etc are top notch and done properly hahaha. Otherwise, it could end in tears.

sprayer

Also - fantastic indoor setup you have there clawhammer. Excellent. A huge amount of effort and dedication put into that.

Also love this wide-screen effect, as orchidboard is having trouble with handling video frames or something.

[WaterWitchin]

Originally Posted by thefish1337

Aerial roots of epiphytic orchids: the velamen radicum
and its role in water and nutrient uptake

the study is not 100% conclusive but it does support the hypothesis that orchids are well equipped biologically to scavenge the first pulse of nutrients. however, I suspect that watering first doesn't really "hurt" because the roots themselves have a number of mechanisms to pull out charged ions from solution so as long as you soaked your plant sufficiently after pre-wetting I doubt it would hurt much other than waste water and time.

Yes, this is the backdrop of whatever I read. Excellent. Gracias for pinning down a piece of it.