Bark media and fertilizer - Orchid Board

notsogreenthumb · #1 07-06-2013, 11:30 PM

I recently just repotted my Phalaenopsis in a mixed media containing Fine grade fir bark, charcoal and coarse perlite.

I read somewhere that because I'm using bark that I need to change from my 20-20-20 to a 30-10-10 because of something to do with the decomposition of the bark messing with nitrogen levels.

What truth is there to this and should I run out and get a different fertilizer? Also, with a different ratio, do I continue with my weekly half strength fertilizing?

Thanks,
Dustin

james mickelso · #2 07-07-2013, 12:36 AM

Not necessary to switch. The bacterial aerobic decomposition of the bark is very slow and the orchid isn't getting food from the bark but food in the water that is soaking into the velamin around the outside of the root. I've read this for a long time but it just isn't so. The root isn't searching through the bark to get food. The root is immobile and awaits food which we give it in the water we put on the orchid.

Ray · #3 07-07-2013, 08:31 AM

James is correct.

That lore is actually based upon fact - from days when orchid potting media ingredients were collected from the forests and the plants maintained in the same stuff for a very long time. That is, starting with a good charge of natural decomposing critters, and letting them have a long time to proliferate.

Not an issue in modern culture.

notsogreenthumb · #4 07-07-2013, 10:58 PM

I've noticed that the bark after a couple days is really quite dry. I've submerged the planter in water and I"m trying to get the bark to really take a good drink. What things should I be aware of when watering my phal in this medium as opposed to the moss I've had in the pots for the last 2 years?

james mickelso · #5 07-07-2013, 11:05 PM

Remember that you are watering the roots. Not the media. It isn't necessary to get the media wet or have it stay wet. When I repot my phals, and most of the rest of my orchids, I don't pre-soak it. It will eventually soak up some moisture but that is just the nature of bark. You are watering the roots (velamin) not the media. Phals can be mounted and the mount stays pretty dry. The important thing here is to make sure you are watering enough to soak the roots. I don't actually like my media staying wet especially during the cooler hours of the night.

notsogreenthumb · #6 07-07-2013, 11:14 PM

I watched a youtube video where the lady waters her orchid in an a pot with no holes. lets it soak for a couple minutes then drains the water fr om both the pot and the orchid and then pops the newly watered orchid back into its pot. Based on what you're saying, this sounds like a pretty reasonable thing to do.

I was pretty discouraged when I repotted, the root system was really quite small and deteriorated. These plants will need much love over the coming year.

james mickelso · #7 07-07-2013, 11:22 PM

The way I water is called the dip method. I have too many orchids to run water through them as I buy my water from a Reverse osmosis machine in front of the drug store down the street.. I fill a 5 gal bucket with 2 gallons of tap water (shudder) and then 3 gals of RO water and I put food and kelpmax in it. I dip the orchids in this bucket for not more than 15 secs. The velamin around the root, the spongy mass that surrounds the thin firm wiry root soaks up water on contact. So to water your orchid you can get a pan or bowl or??? filled with water and just put it in and let it soak up what it wants. Your are watering the roots, not the media.

notsogreenthumb · #8 07-07-2013, 11:36 PM

You have been most helpful

Thank you so much

Wild Orchid · #9 07-07-2013, 11:56 PM

Quote:

Originally Posted by james mickelso

The way I water is called the dip method. I have too many orchids to run water through them as I buy my water from a Reverse osmosis machine in front of the drug store down the street.. I fill a 5 gal bucket with 2 gallons of tap water (shudder) and then 3 gals of RO water and I put food and kelpmax in it. I dip the orchids in this bucket for not more than 15 secs. The velamin around the root, the spongy mass that surrounds the thin firm wiry root soaks up water on contact. So to water your orchid you can get a pan or bowl or??? filled with water and just put it in and let it soak up what it wants. Your are watering the roots, not the media.

Hi James,
One question if I may. Do you not pre-soak roots first? This is one part of watering I find a bit tiring as I've read that first you have to moisten the roots, and then fertilize, which makes one do two soaks for each plant.

I was wondering if this was necessary?

Thanks!
WO

james mickelso · #10 07-08-2013, 12:19 AM

No! Hmm that was easy.

No, I just mix my fertilizer at 1/4 to 1/2 strength and water with that every time I water. That is fairly dilute fertilizer. If you water weekly or so the velamin (the outer spongy covering on the root) readily soaks in water. I mean quickly. In the proverbial blink of an eye. I'll look for the pics of this. There should be no need to soak the plant for a minute or two or three or half an hour. My club had a well known orchid grower give a new talk for us this past week and his method is to pour 20% more water than the volume of the pot your are watering through the plant. That's it. I like to dip mine. Your choice. Roots quickly soak up all the water they can in a short a time as they can.