Does anyone who uses an RO unit for their water put any amount of
untreated tap water back into the RO water for micronutrients? I've
been using an RO unit for my orchids' watering needs for the last two
years. I recently found part of a blog from a few years ago that stated
anyone who uses RO water should add some (an amount wasn't specified)
regular tap water back into it in order to supply micronutrients that
the RO unit removes during the filtration process. I usually add a
little less than 1/16th a teaspoon per gallon of the University of
Michigan formulated fertilizer every time I water my plants (and the
fertilizer container says it's formulated for RO water). Does that
sound like it's enough to fulfill the nutrient needs of the majority of
orchid genera without the need to add tap water back into the RO water,
or should I still add some tap water? I thought I was doing my plants a
favor a couple of years ago when I invested in an RO unit. However,
since what I read indicated that RO water can be tricky to use since it
takes out just about everything from the water and renders it more pure
than rain water (meaning that the plants have nothing left in the form
of nutrients to absorb from the RO water), I'm starting to wonder
whether or not I've been starving my plants.

Steve,

You're already doing the correct thing - no worries. The RO MSU Fertilizer
is designed to add all the necessary micronutrients lost by the RO process.

-Eric in SF
www.orchidphotos.org

"Steve Weaver" wrote in message
ups.com...
the RO unit removes during the filtration process. I usually add a
little less than 1/16th a teaspoon per gallon of the University of
Michigan formulated fertilizer every time I water my plants (and the
fertilizer container says it's formulated for RO water). Does that

The RO fertilizer puts back everything your plants need, but I still think
you're starving your plants.

The MSU study fed their plants at 125 ppm N at every watering. If you're
using the GreenCare formula - the one developed in the study - you're
feeding at about 11 ppm N.

--

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


"Steve Weaver" wrote in message
ups.com...
Does anyone who uses an RO unit for their water put any amount of
untreated tap water back into the RO water for micronutrients? I've
been using an RO unit for my orchids' watering needs for the last two
years. I recently found part of a blog from a few years ago that stated
anyone who uses RO water should add some (an amount wasn't specified)
regular tap water back into it in order to supply micronutrients that
the RO unit removes during the filtration process. I usually add a
little less than 1/16th a teaspoon per gallon of the University of
Michigan formulated fertilizer every time I water my plants (and the
fertilizer container says it's formulated for RO water). Does that
sound like it's enough to fulfill the nutrient needs of the majority of
orchid genera without the need to add tap water back into the RO water,
or should I still add some tap water? I thought I was doing my plants a
favor a couple of years ago when I invested in an RO unit. However,
since what I read indicated that RO water can be tricky to use since it
takes out just about everything from the water and renders it more pure
than rain water (meaning that the plants have nothing left in the form
of nutrients to absorb from the RO water), I'm starting to wonder
whether or not I've been starving my plants.

Hi Steve,

I add 'good' untreated water back into the RO water but not for micros.
Modern fertilizers are pretty good at providing everything the plant needs
and when I do need extra micros products such as Peters STEM are more
controlled. Instead I add the untreated water to help control the mix pH.
If the mix pH gets too far away from something like 5.8 the plant has a hard
time taking up the micros. In terms of N, I feed at strengths 10 to 20
times what you are using (between 100 and 200 ppm N).

Pat

"Steve Weaver" wrote in message
ups.com...
Does anyone who uses an RO unit for their water put any amount of
untreated tap water back into the RO water for micronutrients? I've
been using an RO unit for my orchids' watering needs for the last two
years. I recently found part of a blog from a few years ago that stated
anyone who uses RO water should add some (an amount wasn't specified)
regular tap water back into it in order to supply micronutrients that
the RO unit removes during the filtration process. I usually add a
little less than 1/16th a teaspoon per gallon of the University of
Michigan formulated fertilizer every time I water my plants (and the
fertilizer container says it's formulated for RO water). Does that
sound like it's enough to fulfill the nutrient needs of the majority of
orchid genera without the need to add tap water back into the RO water,
or should I still add some tap water? I thought I was doing my plants a
favor a couple of years ago when I invested in an RO unit. However,
since what I read indicated that RO water can be tricky to use since it
takes out just about everything from the water and renders it more pure
than rain water (meaning that the plants have nothing left in the form
of nutrients to absorb from the RO water), I'm starting to wonder
whether or not I've been starving my plants.

Thank you, Pat, Eric and Ray for the responses to my inquiry. I figured
that my feeding regimen was a bit spartan as far as the total ppm's
went. But in my defense I have quite a few Angraecoid orchids which
seem to resent a lot of fertilizer. So I've been a little hesitant
about giving too high a level of dissolved salts to all of the
Aerangis, Jumelleas, Rangaeris and Oeniellas in my small collection.
The only African orchids I give higher amounts of fertilizer to are the
larger Angraecum species that I have (longicalcar, sesquipedale and
superbum), all of which seem to appreciate fertilizer levels closer to
what I give to my cymbidiums. I'll go ahead and increase the amount of
food that I'm giving to the other plants, however, based on your
feedback. I just get paranoid whenever I scoop out the recommended
amount of fertilizer that's listed on the side of the container and
dump it into a large bucket of water. It looks (to my amateur hobbyist
eyes at least) like a lot of fertilizer. Thanks again for your help.
It's much appreciated.

Steve


Pat Brennan wrote:
Hi Steve,

I add 'good' untreated water back into the RO water but not for micros.
Modern fertilizers are pretty good at providing everything the plant needs
and when I do need extra micros products such as Peters STEM are more
controlled. Instead I add the untreated water to help control the mix pH.
If the mix pH gets too far away from something like 5.8 the plant has a hard
time taking up the micros. In terms of N, I feed at strengths 10 to 20
times what you are using (between 100 and 200 ppm N).

Pat

"Steve Weaver" wrote in message
ups.com...
Does anyone who uses an RO unit for their water put any amount of
untreated tap water back into the RO water for micronutrients? I've
been using an RO unit for my orchids' watering needs for the last two
years. I recently found part of a blog from a few years ago that stated
anyone who uses RO water should add some (an amount wasn't specified)
regular tap water back into it in order to supply micronutrients that
the RO unit removes during the filtration process. I usually add a
little less than 1/16th a teaspoon per gallon of the University of
Michigan formulated fertilizer every time I water my plants (and the
fertilizer container says it's formulated for RO water). Does that
sound like it's enough to fulfill the nutrient needs of the majority of
orchid genera without the need to add tap water back into the RO water,
or should I still add some tap water? I thought I was doing my plants a
favor a couple of years ago when I invested in an RO unit. However,
since what I read indicated that RO water can be tricky to use since it
takes out just about everything from the water and renders it more pure
than rain water (meaning that the plants have nothing left in the form
of nutrients to absorb from the RO water), I'm starting to wonder
whether or not I've been starving my plants.