Fertilizer: Less Is More

[Happypaphy7]

I visited a friend of mine today and had to report this.
I gave her four orchids almost exactly one year ago, and all were doing very well.

NOID compact phalaenopsis ( wish I knew the name because the flower to plant size ratio is great and the color is really nice) grew two large leaves and in two new spikes with many flowers.

Two plants of Tolumnia (the name is too long to list here), each with 5-6 new growths going. I have never had this happen on my Tolumnia of the similar size.

Neostylis Pinky 'Starry Night' grew about 3 new leaves and has 6 spikes going.

All these orchids are sitting on the south window sill with no curtain and no buildings outside shading the window.
She never fertilized them the whole one year. She actually never had live plants before, so she did what I told her to, which was to try and water them not too often but at least once a week. I had to make it simple so she would try her hands on the orchids.

I have also grown my orchids without any fertilization for about one year, and they all performed very well. I actually cannot tell the difference, but I now fertilize because I feel better that way.
I guess orchids have quite a bit of nutrients or elements stored inside them to last for a long time without needing much.

 

[troy]

Orchids is a general word referring to 40,000 different species, I fertilize my slippers at 1/4 strength every week, with different stuff using 3/4 ro- 1/4 tap, if I don't fertilize longer than 2 weeks I get growth problems, all my plants have active growing roots

 

[Ozpaph]

less is more or "weakly, weekly"

 

[Justin]

If you search out the K lite threads on this forum this is the point that rick has been making. That there is enough N in our tapwater to take care of most of their needs.

In my conditions a constant, dilute feed works great...1/16 tsp of 30-10-10.

 

[monocotman]

Weakly weekly

Agree with you all.
I struggled indoors with orchids until I switched to akerne's rain mix plus rain water at every watering. The rate is very low, little more than a good pinch into a 2 gallon watering can.
The subsequent growth improvement was astonishing. Quite how much of this is due to the low feed rate and how much due to the components of the rain mix I do not know. I am just very happy with the results.
My best plants would now not look out of place in a well run greenhouse.
Other things have not changed. The climate indoors is still cooler, drier and has very little air movement compared to a greenhouse. There is also less light. Not seemingly ideal but yet the plants adapt!
The only change has been the feed,
David

 

[Linus_Cello]

Since moving houses in September, I haven't had a chance to fertilize (either k-lite or blossom booster). My plants seem fine, and the Ros Rawdon Jester and Gary Romanga x Sanderianum that I posted threw up a spike. Maybe for me, I don't need to fertilize since I'm using aquarium water, with lots of fish waste "organic fertilizer", to water my plants (all freshwater tropical softwater, e.g. discus).

 

[Stone]

If you search out the K lite threads on this forum this is the point that rick has been making. That there is enough N in our tapwater to take care of most of their needs.

I wasn't going to but....It's completely and utterly wrong to say that. If you want to grow orchids to anywhere near their potential, you have to feed them. If plants are doing ok without feed (for a while) it means there are residual nutrients (usually ammonium and potassium) held in the mix. I have a number of old Paph hybrids which were not fed all winter and most of spring and they showed no signs of needing food but they were well fed the previous summer and the mix contained moss.
A club member recently brought in a sukhakulli with 4 spikes which had not been fed for 3 years or repotted for 5. It's leaves were about 2 inches long and yellow.
So no there is definitly not anywhere near enough N in tap water.

If you like and can post a pic of a Laelia in a basket which has only recieved tap and rain water for the past several years. It's growth is a bit of a joke compared with the well fed plants.

 

[Happypaphy7]

Mike, I think maybe the tap water he tested were from contaminated source. lol

I understand that orchids can get by with low amount of nitrogen, but if enough nitrogen is found in tap water, then that tap water has serious health concern.
Whether one opts to drink out of the faucet or not, tap water is (and must) be tested by the authorities for certain toxins and pollutants, and as I understand, nitrogen is one of them.
It should be in extremely low amount to zero in tap water.
If not, the water has some serious contamination either or both from fertilization in the field or livestock poop runoff.
Time to call the local water department, or sue the farmers in the area, or move to a better place. lol

 

[Brabantia]

I am always surprised when I read the answers which are given on the subject “low feeding” that one never speaks about the effect of the mass roots. During the two last years I feeded to 20 ppm N once per week. I obtained plants which did not grow and which lost many leaves by translocation. End of last year I go to 40 ppm N by week. I noted a net improvement of the growth and a reduction of leaves yellowing.I must say that I never have Paphiopedilum which had the mass roots I show sometimes on this forum. My opinion is that it is necessary to fertilize sufficient to ensure the plant growth (especially if the roots mass is relatively low). Obviously while remaining in a range of salt concentrations which are not aggressive for the roots. I evaluate this concentration around 350 mgr/l.
Remainder: I am using the MSU belgian copy.

 

[Happypaphy7]

Just so you know, I'm just "reporting" what I observe.
I'm not advocating any sides, but I do believe many people over-fertilize.

So these orchids of my friends, in the last one year of no fertilization, this is what happened as far as "loss" since I mentioned about the "gain" already in the very first post.

NOID phal- yellowed and lost one bottom most leaf.
Tolumnias- each lost about a couple bottom leaves.
Neostylis Pink- not a single leaf lost.

All the newer leaves on these plants are larger than the previous leaves, and the color is nice healthy green.

In the past when I stopped fertilizing for one year (this happened my accident, and not intentionally done), I had not noticed any excessive loss of leaves, just typical yellowing of one bottom leaf per plant or zero loss.
I had paphiopedilum of all kind except for the multis, dendrobiums of differnet sort, cymbidiums, oncidium hybrids, phalaenopsis hybrids, and other genera.
Maybe if I had gone for another year without fertilizing, things might have turned for the worse and I might have seen some effects of starvation.
This experience just made me think about how uptight many people are about fertilizing, especially when I hear people call it "plant food".

Of course, fertilization is needed under cultivation.

 

[paphioland]

To grow Paphs to potential and at maximal growth rate you need to fertilize frequently.

 

[Ozpaph]

The question is "How much is enough"?........................to which there is significant divergence of opinion.

Paphioland, what is your regimen?

 

[Rick]

http://pacewater.com/wp-content/uploads/2011/02/nitrate_removal.pdf

In this presentation a warmwater artificial wetlands was able to suck up 1.2kg N per acre per day of nitrate (the nitrate is not limiting in the system

This is equivalent to sucking up 0.0275mg of N per square foot per day.

Or if you had a Cattail or Bull Rush plant in a 6" pot its equivalent to using 0.006875mg of N per day.

So you could apply 0.6875 ml (about 13 drops) of a 100ppm N fert solution to a 6" pot and max out the nitrate need of that plant on a daily basis.

 

[Rick]

http://www.upc.edu/growingmediacomp...growingmediacomposting2011.ISHS/s4-8-restrepo

 

[Rick]

Need to add interpretation to the above presentation on nitrification inhibition in rose culture.

 

[Rick]

The presentation on pot culture of roses in Columbia soilless media is illustrative (its not that different from orchid pot culture).


The overall conclusion was:
1) nitrifying bacteria convert ammonia to nitrate very quickly
2) whether ammonia or nitrate, the plants use very little of it with the bulk leaching out.
3) ammonia is not stored in the potting media

 

[Happypaphy7]

Rick,

If plants use very little of nitrogen available and majority of N is leached out of soil, then why do you suggest limiting the N in your fertilizing philosophy??

For the purpose of stopping the waste of nitrogen and saving the environment?

 

[Rick]

Rick,

If plants use very little of nitrogen available and majority of N is leached out of soil, then why do you suggest limiting the N in your fertilizing philosophy??

For the purpose of stopping the waste of nitrogen and saving the environment?

You might find the line in the rose presentation that they thought there were physiological problems associated with excess N.

Also high levels of N support a bacterial flora that is not conducive to root health.

Just like in aquarium culture you want to feed the fish and not feed all the bacteria scavenging the leftover fish food. You want the bacteria to eat the fish waste (which has a lot of ammonia actually).

So yes "waste not want not", but turning your pot into a cesspool isn't good for the plant either.

This appears to be why orchid folks find success in mounting or open mix systems. Very little of what you dump on the plant sticks, and what does stick is easy to wash away with subsequent non supplemented watering.

I found large pulse feeding to be a delicate balancing act which for me has very little forgiveness.

 

[Stone]

So you could apply 0.6875 ml (about 13 drops) of a 100ppm N fert solution to a 6" pot and max out the nitrate need of that plant on a daily basis.

Crazy talk! :rollhappy:
That is supposing the plant finds all the N supplied from 13 drops and there are no microbes at all to use N and that the roots of a pot plant has the same surface area as one in the field. Wrong on all counts. You need to supply N at a much higher rate than that just for the microbes in a bark media. That's before the plant sees any at all.

I think maybe too much calculating and not enough practice Rick? As you may know I grow many plants besides orchids. If I gave 13 drops of 100ppm N per day to my plants in 6'' pots they would very simply starve.
To get maximum growth out of my 6'' stockplants (trees shrubs grasses etc) I give them 2 forms of slow release fertilizer (osmocote at about 1 teaspoon at the start of the season and organic meal (blood and bone type) at about 2teaspoons per month) and a weakly drench of full strength Hydroponic fertilizer which contains about 150ppm N. A drench being about 0.5 litres not 13 drops!
Less than this amount of N and the plants do not grow as fast.
I have not reached a stage yet where I can say I have applied too much (judging from the growth response)
Orchids are of course a different proposition but the above 13 drops is bordering on the rediculous.

 

[Stone]

This appears to be why orchid folks find success in mounting or open mix systems. Very little of what you dump on the plant sticks, and what does stick is easy to wash away with subsequent non supplemented watering.

Th roots of my Phals on mounts are surrounded with at least 100ppm N everytime they see water. You can see the roots turn from white to green which means they are soaked with a solution containg 100ppm N every day.
The only time they see just water is when its very hot and I have to water more often. They are thriving.