As i have been growing orchids for a while now , i have been dabbling with
ppm/PH and the affects the fertilizers have on other compounds.I have
increased the ph as i use rain water,to around 6.6.Just to be inquisitive i
poored my feed mix through 3 of my pots and caught the excess from the
bottom.I tested this and the ph was alot lower than i thought i would be,
5.0,5.5, 6.4 all 3 of these plants grow in a bark/spag/perlite mix.The first
2 pots the ph is on the low side.So am i reading too much into this or is
there a issue here.As the feed mix is becoming too acidic when poored
through the bark mix,does this mean this is the ph the plants are
absorbing,if so do i need to compensate this by increasing the ph further.I
have only just started to take note on the ph levels,so my rain water ph is
around 5.5,so what ph have my plants been getting.Going by what i have found
with these 3 pots tested ,around 4.5!Way to low.It is a interesting and
logical subject once you read,read again,read/read again ,it starts to sink
in the affects low/high ph have on orchids.
Hope you get what i mean here and i am not sounding like a obsessed
nutter.My regime before was a standard fert 1/4 strength /rainwater when i
could be bothered to feed.I knew this was`nt the best regime for my plants
and it fitted with the time i was willing to give the plants.Things have
changed and i am willing to give them more.
Thanks Keith

I cannot claim to be an expert in this arena, but there are lots of things
that affect the pour-through pH - how dry the medium was to start with, how
much liquid is poured through, volume of medium in the pot, how well
buffered the nutrient solution is, the makeup of the medium itself, and
indirectly, even the time of day you test, as the gas exchange occurring at
the roots will also have an effect, changing the pH of the liquid already in
the medium.

If the plant is pretty much only respiring (nighttime), that
early-in-the-morning pH may be different than if the plant has been doing
that and photosynthesizing, and you had sampled later in the day.

There was a discussion on the S/H Forum some time ago about this, and we
found cases in which the water in the reservoir could be very acidic - in
the 3- to 4 range. From that we concluded it was actually an advantage to
water more frequently to flush that away and provide a fresh solution with a
higher pH. I have applied that philosophy to non-s/h plants too, using more
open, less water-retentive media, and watering often.

I don't know that I'd obsess over the readings you saw, Keith. How are the
plants doing? If they are visibly suffering, I'd be concerned, but
otherwise just let them be your guide.
--

Ray Barkalow - First Rays Orchids - www.firstrays.com
Plants, Supplies. Books, Artwork, and lots of Free Info!


"keith kent" wrote in message
...
As i have been growing orchids for a while now , i have been dabbling
with ppm/PH and the affects the fertilizers have on other compounds.I
have increased the ph as i use rain water,to around 6.6.Just to be
inquisitive i poored my feed mix through 3 of my pots and caught the
excess from the bottom.I tested this and the ph was alot lower than i
thought i would be, 5.0,5.5, 6.4 all 3 of these plants grow in a
bark/spag/perlite mix.The first 2 pots the ph is on the low side.So am i
reading too much into this or is there a issue here.As the feed mix is
becoming too acidic when poored through the bark mix,does this mean this
is the ph the plants are absorbing,if so do i need to compensate this by
increasing the ph further.I have only just started to take note on the ph
levels,so my rain water ph is around 5.5,so what ph have my plants been
getting.Going by what i have found with these 3 pots tested ,around
4.5!Way to low.It is a interesting and logical subject once you read,read
again,read/read again ,it starts to sink in the affects low/high ph have
on orchids.
Hope you get what i mean here and i am not sounding like a obsessed
nutter.My regime before was a standard fert 1/4 strength /rainwater when i
could be bothered to feed.I knew this was`nt the best regime for my plants
and it fitted with the time i was willing to give the plants.Things have
changed and i am willing to give them more.
Thanks Keith

Thanks for the response Ray, the plants seem to be doing good.I will see
what they do .
Thanks Keith

"Ray B" wrote in message
news:mycBi.1176$2p5.27@trndny05...
I cannot claim to be an expert in this arena, but there are lots of things
that affect the pour-through pH - how dry the medium was to start with, how
much liquid is poured through, volume of medium in the pot, how well
buffered the nutrient solution is, the makeup of the medium itself, and
indirectly, even the time of day you test, as the gas exchange occurring at
the roots will also have an effect, changing the pH of the liquid already
in the medium.

If the plant is pretty much only respiring (nighttime), that
early-in-the-morning pH may be different than if the plant has been doing
that and photosynthesizing, and you had sampled later in the day.

There was a discussion on the S/H Forum some time ago about this, and we
found cases in which the water in the reservoir could be very acidic - in
the 3- to 4 range. From that we concluded it was actually an advantage to
water more frequently to flush that away and provide a fresh solution with
a higher pH. I have applied that philosophy to non-s/h plants too, using
more open, less water-retentive media, and watering often.

I don't know that I'd obsess over the readings you saw, Keith. How are
the plants doing? If they are visibly suffering, I'd be concerned, but
otherwise just let them be your guide.
--

Ray Barkalow - First Rays Orchids - www.firstrays.com
Plants, Supplies. Books, Artwork, and lots of Free Info!


"keith kent" wrote in message
...
As i have been growing orchids for a while now , i have been dabbling
with ppm/PH and the affects the fertilizers have on other compounds.I
have increased the ph as i use rain water,to around 6.6.Just to be
inquisitive i poored my feed mix through 3 of my pots and caught the
excess from the bottom.I tested this and the ph was alot lower than i
thought i would be, 5.0,5.5, 6.4 all 3 of these plants grow in a
bark/spag/perlite mix.The first 2 pots the ph is on the low side.So am i
reading too much into this or is there a issue here.As the feed mix is
becoming too acidic when poored through the bark mix,does this mean this
is the ph the plants are absorbing,if so do i need to compensate this by
increasing the ph further.I have only just started to take note on the ph
levels,so my rain water ph is around 5.5,so what ph have my plants been
getting.Going by what i have found with these 3 pots tested ,around
4.5!Way to low.It is a interesting and logical subject once you read,read
again,read/read again ,it starts to sink in the affects low/high ph have
on orchids.
Hope you get what i mean here and i am not sounding like a obsessed
nutter.My regime before was a standard fert 1/4 strength /rainwater when
i could be bothered to feed.I knew this was`nt the best regime for my
plants and it fitted with the time i was willing to give the
plants.Things have changed and i am willing to give them more.
Thanks Keith