Nutrient deficiencies

[calvin_orchidL]

Hi everyone
Just curious whether or not anyone has experience with the different symptoms seen as a result of nutrient deficiency in orchids. I know it's quite rare, and many symptoms are shared amongst lots of things

I stumbled upon an article that seems to do some of these studies, and they mention that orchids typically respond slowly to deficiencies, mainly because they are highly efficient at mobilizing nutrients from other/older parts of the plant (in other words, self cannibalism!) However, they don't list observable symptoms

I water with RO water which is quite pure. From basic chemistry, it seems that not only is this water missing some basic nutrients, but it could also be leaching out nutrients from the media. I was using MSU's RO water fertilizer, but a few months ago I spilled some water into the fertilizer bottle and everything ended up clumping together, so I had to chuck the whole thing out. As a result, I haven't been fertilizing for a while, and I'm starting to notice some funny things happen with my plants.

[axle]

We've got good water here in Toronto, you can mix 50/50 with RO or just use straight tap water.
I personally always use tap water then add nutes and other additives on top of that. No problems here.

Another thing to watch with straight RO water is apparently it's pH, while RO water will have a pH of 7, it has no carbonates to buffer pH so it is easily influenced to change.

[King_of_orchid_growing:)]

It's not always easy to detect the nutrient deficiencies in orchids, because sometimes each species or genera are way different from each other. Unless you've got multiple specimens of the same species, you can't tell what's up from down, so to speak.

I can give you an example of calcium deficiency in Habenaria carnea...

They lose their shine. The leaves are supposed to glisten in the light. Underneath the leaf, they should look powdery.

Subtle, right? But that's just an example.

Another nutrient deficiency is also leaf buckling. Yes, this happens when there's not enough water also, but it's also caused by a nutrient deficiency. Not sure which one.

[calvin_orchidL]

Originally Posted by axle

We've got good water here in Toronto, you can mix 50/50 with RO or just use straight tap water.
I personally always use tap water then add nutes and other additives on top of that. No problems here.

Another thing to watch with straight RO water is apparently it's pH, while RO water will have a pH of 7, it has no carbonates to buffer pH so it is easily influenced to change.

Thanks for the replies so far - that's a good point about different genera.

Toronto water is great and I was using it happily until a water softener was installed in our house. Now all the water is softened and toxic, and I haven't been able to figure out how to divert the water flow to just give me good tap water. That's a good point about the pH...I'm going to try and see if I can get a non-softened faucet put in.

[phragguy]

I have used R,O water for 12 years and not had a problem,I use the MSU fertilizer for R.O.
Check your P.H. I find the fertilizer brings it down so I have to up it.

[calvin_orchidL]

Originally Posted by phragguy

I have used R,O water for 12 years and not had a problem,I use the MSU fertilizer for R.O.
Check your P.H. I find the fertilizer brings it down so I have to up it.

Thanks Phragguy. I will defintiely check pH once I get some pH paper. I used the MSU fertilizer for R.O - do you predilute it and have a stock solution? I find that since I make up water in such small batches, I'm basically only tossing in very little fertilizer (a few grains!) so I was thinking I should make a concentrated solution that I dilute out every time which should be a bit more reliable. Also, have you had problems with the fertilizer clumping together? I must have gotten some water in there or something, but it clumped together and actually turned blackish-green...weird.

I found this website that details some of the symptoms...I'm starting to see yellowing in some of my plants that looks like fertilizer burn (but definitely is not, since I fertilize so seldomly)...it's not the roots because everything has extensive root systems...and I've grown long enough to somewhat know that this isn't seasonal/natural leaf drop. New growths are also not growing properly. I'm suspecting nitrogen/molybdenum deficiency but that's just an uneducated and naiive guess.

[got ants]

Interesting topic. Being a newb, I have no clue if I'm doing anything right or wrong.

as for watering, I have 3 options, the abundant rain we have here in south florida, rain water collected in buckets from roof run off, or well water from my sprinkler pump.

I also have tap water but with chlorine and other chemicals in it, I've always considered it toxic.

So, just how do you test for PH?

[Ray]

King is right about the difficulty of diagnosing mineral deficiencies, but I have a very general discussion of the nutrient minerals on my website (Fertilizers & Plant Nutrition) that might be of some help.

By the way, you really shouldn't have pitched the clumped fertilizer. If you can estimate the amount of water spilled into it, deduct that from the weight of the fertilizer, and you can make up a concentrated solution for further dilution. For the Greencare RO formula, for example, you make up one gallon of solution using 1 pound of fertilizer, then you can use that at one ounce per gallon. (For you metricated folks, that's a 120g/L concentrate, for use at about 7.5ml/L.)

Even if your estimate is not so great, you'll still be in the ballpark, and it beats not feeding your plants at all. Don't forget, orchids get essentially no nutrition from the medium unless it's decomposing, and that is bad for the roots. You've not been leaching from the medium, you've been leaching from the plant.

[calvin_orchidL]

Originally Posted by Ray

King is right about the difficulty of diagnosing mineral deficiencies, but I have a very general discussion of the nutrient minerals on my website (Fertilizers & Plant Nutrition) that might be of some help.

By the way, you really shouldn't have pitched the clumped fertilizer. If you can estimate the amount of water spilled into it, deduct that from the weight of the fertilizer, and you can make up a concentrated solution for further dilution. For the Greencare RO formula, for example, you make up one gallon of solution using 1 pound of fertilizer, then you can use that at one ounce per gallon. (For you metricated folks, that's a 120g/L concentrate, for use at about 7.5ml/L.)

Even if your estimate is not so great, you'll still be in the ballpark, and it beats not feeding your plants at all. Don't forget, orchids get essentially no nutrition from the medium unless it's decomposing, and that is bad for the roots. You've not been leaching from the medium, you've been leaching from the plant.

Thanks for the advice, Ray. I still do have that fertilizer...I only figuratively chucked it.

I actually have no idea how much water spilled into it...I found it clumped together one day, and so I just assumed I had gotten some moisture in there either by not closing the lid properly or whatever. A stock solution which I can dilute out would be useful, because since I don't have too many plants, I end up only putting in a very small quantity of the stuff each time I water. How long does the reconstituted stuff last? ie can I store the concentrated stock for a while?

I never knew RO water was actually that potent - either way, I'll probably just buy a new vial of fertilizer at the next OS meeting which is the only source of the stuff up here. My bottle is only 6 bucks so it's easy to get another one. In the meantime, I'll weigh out some and guestimate how much more I need to account for the water, and I'll also check the pH of my water with and without fertilizer, just to be sure.

Thanks again everyone