Feeding Potless Vanda

[K-Sci]

Originally Posted by Ray

I ...
The more precise method is to weigh the fertilizer in the right ratio for the fertilizer formula.
...

The much easier method, (and close enough), is to divide 2 by the %N (as a whole number), giving you the teaspoons/gallon.
...

I love answers like this one - both the technical and simplified. Thanks Ray!

---------- Post added at 07:22 PM ---------- Previous post was at 06:55 PM ----------

Originally Posted by estación seca

In his older book on Vanda growing (which you can still find for sale) Martin Motes reported...
he fertilizes every 5th watering, using a fertilizer injector for the hose. The solution delivered to the Vandas was 1 Tablespoon (15ml) of 20-20-20 with micronutrients per gallon (3.78 liters) of water.

Wow! That's about twice what I use. I use 1/4 tsp/gal roughly every two weeks. If I saved it up and did it only once every 5 weeks that would be 5/2 * 1/4, which is still only 5/8ths tsp, or a slightly mounted 1/2 tsp.

He has since said he switched to a MSU formulation rather than a 20-20-20 formulation. I've looked but I can't find him saying whether he still uses 1 Tablespoon per gallon, but I can assure you that amount makes Vandas grow fast.

MSU is 13-3-15, which wouldn't be far off from the rate I calculated for my plants above.

That is a lot more than other people recommend, but Motes grows Vandas for a living.

In the book Motes wrote a properly fertilized Vanda has a zone of lighter green at the very base of the newest emerging leaf that is about a centimeter wide. If the lighter green band is not this wide, the plant needs more fertilizer. If the lighter green band is wider, the plant is being overfertilized.

By that measure I'm underfertilizing.
I've been watering 3 time/day morning, noon, and evening using a watering can and rainwater or RO. I don't use a hose because our water has a lot of carbonates. It leaves white residues that won't come off - even with mild acids. It leaves a build up on everything from toilets to showers. When I lived in Maine, the water deposits would wipe off with water.

I have written this here before and OB members have not been able to understand what I meant. I think this might be because they don't fertilize much, and there is no light green band. I have been told here Vandas might make 2-3 new leaves per year. When properly fertilized they grow much faster than most people would imagine.

I have a light green line that is not very wide. I'm going to double the concentration I use for Vanda and see what happens.

I wonder if heavy feeding can be extrapolated to include Vanda (Neofinetia) falcata. I know many growers don't fertilize at all. I fertilize 1/4 tsp/gal 30% nitrogen every couple months. ...Perhaps a thread for another day.
[quote]

---------- Post added at 07:53 PM ---------- Previous post was at 07:22 PM ----------

Originally Posted by Shadeflower

...
As a sidenote: stunted orchid leaves have nothing to do with underfertilizing. That is a sign of stress and can even be caused by roots performing badly in the pot.

I wouldn't call it "stunted", but the new leaves are smaller than the earlier leaves.

Things that cause stress include,

going down the line
wrong temperatures, day or night,- I live in central Mississippi where the mid-summer temps reach 95F day/75F night from mid-June to mid-September. Of course spring and fall are far more moderate. During the winter with heating it is about 76F day/60F night. Winter also lasts about 3 months.

overfertilizing - I doubt it in my case.

not enough healthy roots Mine has more root mass than top.

not watering the orchid enough - three time/day should be enough.

or the substrate doesn't dry fast enough. - Mine isn't in a pot. If you didn't see it already, I included a picture.

Too little light might play a role Mine gets 50% of full sun (85% glazing, 60% shad cloth) morning to just past mid day and near full sun for a couple hours late in the day (sun shines through the clear glass end of the greenhouse).

but most often transport stress is the most likely reason for smaller leaves. - N/A

It is extremely hard to learn how much to feed an orchid that is going through a stressful transition period so it helps to have a ppm meter so one doesn't have to guess on an orchid that will develop stunted growth whether you feed it perfectly or not. Feeding too little might reduce the orchid size a bit or produce a bit of yellowing on leaf edges but it is nothing that can't be rectified the following year, feeding too much does much bigger damage
...
If you compare that to a vanda, the vanda will much prefer to receive the right dose of fertilizer every time it gets watered over no fertilizer for a lot of waterings and then far too much to make up for the lack in nutrients all week. So learn from Rob and add squash to your glass every time.

This seems like sound advice. I could pro-rate the amount using the method Ray described and keep a special watering can just for morning watering.

[Shadeflower]

K-sci, it sounds like you are happy with motes method.
His book is based on growing methods from the 70's - I just believe our methods have been improved as time went on.

I had a look at my Vanda's and I can't see this light green line he mentions. To me it sounds like nothing anyone can prove or disprove. I have got a light green line on my cymbidium. Does that mean my cymbidium likes to dress up as a vanda in disguise? Just for reference all plants in these pictures have been fed the same fertilized water concentrations all year at 25ppm N. It might be hard to judge how much smaller the neofinetia's are compared to the cymbidium but there is a big size difference making my feed for the cymbidium rather weak but the light green line would indicate it is being overfed? Maybe it doesn't apply to the cymbidium which is the only one I could discover a light green line on. I would email mr motes if I really cared but I don't really and I doubt he'd care to update his book.

edit: I tried to find a well grown vanda pic on the forum, I came across this one and I honestly tried to spot the light green band but I can't. There are plenty of vanda pics online. I just wasted half an hour trying to find the band and different sized examples of such a band and I will leave the discussion to be continued another day

Vanda Denisoniana x Mimi Palmer

[K-Sci]

Originally Posted by Ray

I always water with a water breaker on the hose end. I helps simulate a heavy rain, watering and aerating.

It doesn't rain hard water here, so I get closer to natural using rainwater and RO 90% of the time. When it is really hot I hose down the isles and mist with tap water mid-day. I hate to mist with our city water because is very high in chlorine and the calcium leaves white deposits on the leaves.

...
The much easier method, (and close enough), is to divide 2 by the %N (as a whole number), giving you the teaspoons/gallon.

For Miracid, which is 30-10-10 that would be 2/30% = 1/15

The 20-20-20, therefore, would require 2/20=1/10 teaspoon/gallon for a 25 ppm N solution.

As that would be a pain to measure, I recommend making a concentrate. Let’s say you want to dispense a tablespoon of liquid fertilizer concentrate to make a gallon of usable solution. Each tablespoon would have to contain that 1/10 teaspoon of powder, and as there are 256 tablespoons in a gallon, you simply dissolve 256/10 (either 25 or 26 are fine) teaspoons of powder in a gallon, the mix up your final solution using a tablespoon of that.

So in my case that would be 256/15 =17 tsp/gal. Easy enough.

Edit: If instead of 25ppm per day every day, the equivalent amount of 20-20-20 is applied once every 5 weeks it would be 35 * 1/10 = 3.5 tsp/gal. Given this, 1/Tbs /gallon every 5 weeks doesn't seem so over the top.

[Ben_in_North_FLA]

I will second Motes methodology and confirm that if you want a solid bloom effort from from vandas you have to feed a TBSP per gallon rate.
A TSP will let them grow nicely with scarce bloom if any.

[Shadeflower]

and an apple a day will keep the doctor away

sry couldn't help myself seeing your avatar pic

[Ray]

Originally Posted by Ben_in_North_FLA

I will second Motes methodology and confirm that if you want a solid bloom effort from from vandas you have to feed a TBSP per gallon rate.
A TSP will let them grow nicely with scarce bloom if any.

Don’t forget you have to include the concentration and the frequency of application in that!

How often does Motes feed their plants at a tablespoon/gallon, and using what formula fertilizer?

When I was feeding my vandas using K-Lite (12.9% N) at the equivalent of 1/10 teaspoon/gallon, they were getting thoroughly drenched daily, year round, and in warmer months, 2 or 3 times a day. They bloomed very well.

[K-Sci]

Originally Posted by Shadeflower

K-sci, it sounds like you are happy with motes method.
His book is based on growing methods from the 70's - I just believe our methods have been improved as time went on.

There's no need for concern. I can see why it might seem as though I liked Mote's approach, but I'm not comfortable with the idea of applying 20-20-20 at 1Tbs/gallon. I honestly don't know why the droplets didn't kill the root tips as the solution concentrated through evaporation.

What I liked and gleaned from Mote's approach is that he used much more fertilizer than I am currently using. This was confirmed by the calculation I put in my last post to Ray. Specifically, the dosing Ray described -- 25ppm applied daily (1/10tsp/gal 20-x-x) -- equates to 1-1/2Tbs/gal if the powder were saved for 5 weeks and mixed with the same amount of water. This too is a much more than I've been using. At this point I prefer Ray's approach. I started using it yesterday.

I had a look at my Vanda's and I can't see this light green line he mentions. To me it sounds like nothing anyone can prove or disprove.

Like Ray, I'm a scientist by training. I see the narrow light green line as an additional data point suggesting that I'm probably not fertilizing enough. I like data and I like multiple test methods. I'm in Mississippi. My sunny mid-summer days at 95F days and 75F nights. I suspect that the resulting rapid growth would likely make my line wider than Motts. The line should also vary by grex, and as you point out next, species.

... all plants in these pictures have been fed the same fertilized water concentrations all year at 25ppm N. It might be hard to judge how much smaller the neofinetia's ...

Full stop. This is interesting. I have around 75 different Neofinetia.
So you are watering Neos with 25ppm? It is a Vanda, but many Neo growers/collectors don't fertilize Neos or fertilize very little. What effects does this have?

... compared to the cymbidium

Cymbidiums are another heavy feeder.

but there is a big size difference making my feed for the cymbidium rather weak but the light green line would indicate it is being overfed?

Some of what you're wrote was a bit condescending, or maybe just sarcastic. I'm not offended, just commenting.

edit: I tried to find a well grown vanda pic on the forum, I came across this one and I honestly tried to spot the light green band but I can't. There are plenty of vanda pics online. I just wasted half an hour trying to find the band and different sized examples of such a band and I will leave the discussion to be continued another day

I see that you like facts and data too. The time wasn't wasted. Not being able to find confirming data is data too.

Vanda Denisoniana x Mimi Palmer

I think the light green on your cymbidium is at the tsuke.

K-Sci

---------- Post added at 07:24 AM ---------- Previous post was at 07:20 AM ----------

Originally Posted by Ray

Don’t forget you have to include the concentration and the frequency of application in that!

How often does Motes feed their plants at a tablespoon/gallon, and using what formula fertilizer?

When I was feeding my vandas using K-Lite (12.9% N) at the equivalent of 1/10 teaspoon/gallon, they were getting thoroughly drenched daily, year round, and in warmer months, 2 or 3 times a day. They bloomed very well.

Ray, you may not have seen the comment I added at the end of my last reply to you. Your 25ppm application equates to 1-1/2Tbs once every 5 weeks. The dosing method probably doesn't equate 1:1, but 25ppm daily is a lot of fertilizer. Motes only used 1Tbs.

K-Sci

[Shadeflower]

k-sci,
thanks for addressing me.
You are absolutely correct that I was being a bit sarcastic just because I get ignored a lot. Sorry.
You never mentioned you had 75 Neo's

But even though what I wrote was written in a sarcastic manner, I do not lie about my numbers.

Yes the Neo's get fed at 100-150ppm total fertilizer concentration, exactly the same as the cymbidium which as you rightly realize is considered a heavy feeder. Maybe now my point makes more sense.
I have now doubled the strength for the cymbidium as it is producing a new bulb at phenomenal pace and was starting to show a little bit of yellowing.

I look at my orchids and try to read the signs they give me. I could start feeding my neo's more but I've tried it in the past and ended up causing roots to turn brown hence my belief but these discussions always end up with nobody believing anything other members write because so much made up stuff gets thrown in, making it very necessary to question what other members are writing is actually true, like the green line theory, nobody in the history of growing vanda's has made this claim about the green line except apparently mr motes yet now suddenly I'm supposed to believe it can tell me what my orchid needs?

[Ray]

If you do the calculations of the chemical processes going on within a plant to fix carbon (i.e., to grow), pretty much any plant must consume and process about 5g of NPK and about 200 lb of water,

For bare-root plants, that uptake occurs ONLY with the saturation of the velamen at the instant of feeding. Let's try a theoretical example:

A vanda in a slat basket with no medium, with its roots wetted, can only absorb what hits the roots and is immediately absorbed by the velamen. If those roots are 3/8” in diameter and the velamen is 1/8” thick, each inch of root length has 0.01943 in3 of velamen (let’s call it 0.02 in3 for convenience) which is about 0.32cc. Let’s also assume it can absorb 100% of that volume (it’s bound to be a bit less in reality).

A 25 ppm N solution of K-Lite requires 0.1925g fertilizer per liter, meaning there is 0.0001925g in a cc. That means that each inch of the vanda root can absorb 0.0001925 x 0.32 = 0.00006g of fertilizer. A mature vanda might have what? 20 feet of roots? If that’s correct, at each watering, it can absorb 240 x 0.00006 = 0.015g of fertilizer. (That assumes 100% of the liquid is absorbed with no evaporation.) If growing a pound requires 5g of fertilizer, that would mean that this vanda should do that in about 333 waterings. Double the fertilizer concentration and you, theoretically, halve the time.

However, let's not forget that fertilizer is only ONE parameter that affect growth, and it is a minor one at that. My greenhouse in PA and Motes' in FL have drastically different annual light, heat and humidity profiles, so while Motes' plants might be able to use a lot of fertilizer, mine probably cannot, due to other limitations.

[estación seca]

Originally Posted by Ray

How often does Motes feed their plants at a tablespoon/gallon, and using what formula fertilizer?

I wrote the answer to those questions in my first post to this thread.