Wild Orchids - Roots and Nutrition

[Rick]

Looking into what nutrients lichens might provide for orchids I found this paper..

http://www.hindawi.com/journals/chem/2011/420673/abs/

It seems at least one species of lichen is nutrient rich based on the analysis in the report. About everything an orchid needs except Nitrogen.
This table is copied from the paper..

Table 2. Mineral composition of E. cirrhatum
Element Quantity, ppm
Phosphorus (P) 24.67±0.57
Potassium (K) 1542±1.52
Magnesium (Mg) 1506±1.15
Calcium (Ca) 5191±1.00
Iron (Fe) 893.7±1.10
Zinc (Zn) 66.3±0.60
Manganese (Mn) 53.13±0.32
Copper (Cu) 5.83±0.35

"rich" is a fairly relative term. These seem like big numbers but for perspective how much moss (by volume) does it take to make a kilogram?

1500 ppm is 1.5grams for every 1000 grams of dry moss (and live moss is 90% water by weight).

And this is total material not the instantaneous bio available material readily available to orchids.

So if the amount of moss in contact with the orchid roots comes to a couple of grams (wet). Then consider multiplying these values by 0.000001 for the amount liberated to a single orchid plant during a rain event.????

You might also want to look at the nitrogen fixing capabilities of lichens and they may pass through a significant amount of fixed atmospheric nitrogen on to the orchid.

 

[cnycharles]

The dust (source of nutrients) is in the air, from everywhere. I've seen pics of dust from Africa reaching other continents, and dust from china reaching North America easily (satellite photos)

Okay, didn't see page 2 on my phone before replying... I had read in past that nitrogen ended up in available form from atmosphere when lightning present. A while back, don't have citations
Sent from my iPhone using Tapatalk

 

[Ray]

Jumping back to the mechanical side of this a moment - the roots among the moss strands - I think I'll experiment with some synthetics substrates.

How about a raft of EcoWeb with a cover of Aquamat to provide moisture and nutrient storage, with the roots arranged over the surface. Then, the top of the roots loosely "blanketed" with another layer of the moist fabric?

 

[gonewild]

"rich" is a fairly relative term. These seem like big numbers but for perspective how much moss (by volume) does it take to make a kilogram?

The numbers are big and show that lichens have a substantial amount of nutrients that orchids might access. But that does not mean that orchid roots acquire a large amount at any one time.

1500 ppm is 1.5grams for every 1000 grams of dry moss (and live moss is 90% water by weight).

And this is total material not the instantaneous bio available material readily available to orchids.

Yes and it looks like orchid roots only contact lichens directly in parts of the root system. Certainly lichens are not leaching out all of the minerals they contain.

So if the amount of moss in contact with the orchid roots comes to a couple of grams (wet). Then consider multiplying these values by 0.000001 for the amount liberated to a single orchid plant during a rain event.????

I don't think the rain events are what releases the nutrients. Sure nutrients leach out with a rain but I think the orchid roots that are in contact with lichen acquire it with dew each night. The nutrients leched out with rainfall are very dilute where dew will have higher nutrient content. But just because the content is higher does not mean the orchid roots are in a large amount of nutrients. An orchid root may be a foot long but only a small part is in contact with a lichen.

You might also want to look at the nitrogen fixing capabilities of lichens and they may pass through a significant amount of fixed atmospheric nitrogen on to the orchid.

Yep. lichens are fixing nutrients from the atmosphere. That explains where the plants get all the Calcium to grow their mass. They certainly don't get it only from decaying leaves.

The high nutrient content only shows that this could be where orchids acquire nutrients and how much they acquire. But looking at the root system placement as it grows naturally It looks like they only get a small amount but constantly.

The most interesting part of the lichen idea is that it shows that Phosphprous is one of the lowest nutrients present. Assume all the nutrients leach from the lichens equally and this reinforces the K-lite ratios.

 

[gonewild]

The dust (source of nutrients) is in the air, from everywhere. I've seen pics of dust from Africa reaching other continents, and dust from china reaching North America easily (satellite photos)

Okay, didn't see page 2 on my phone before replying... I had read in past that nitrogen ended up in available form from atmosphere when lightning present. A while back, don't have citations
Sent from my iPhone using Tapatalk

I think that nitrogen that is fixed by lightning comes down dissolved in rainfall. If that is correct there is not enough to to be the main source for orchids. It adds to the total and maybe the specialized orchid roots make great use of it.

 

[gonewild]

Jumping back to the mechanical side of this a moment - the roots among the moss strands - I think I'll experiment with some synthetics substrates.

How about a raft of EcoWeb with a cover of Aquamat to provide moisture and nutrient storage, with the roots arranged over the surface. Then, the top of the roots loosely "blanketed" with another layer of the moist fabric?

That comes very close to what is in Nature.
The orchid roots grow through the moss but the moss is not very dense. A very high percentage of the root is surrounded by air space with only sporadic contact with moss. The same is true in orchids growing on the ground in leaf litter. The litter is fluffy and roots grow between the leaves. I found a Lycaste (Ida) growing this way. The roots have hairs that provide separation between the leaf layers. This means that most of the root is surrounded by air even with terrestrial species. I will try to post pics of this soon.

So your idea is good. Use the materials to create a moist humid air space for the roots. But think of a way to have a constant nutrient supply. It may be that the roots need to be constantly moist so support bacteria, fungi, algae and lichens within or on the spongy root. These organisms may be what supply the nutrients.

If the above is correct it is a reason to only use a very weak fertilizer solution, but constantly. Or it may be a reason why some people claim to have great growth without using any fertilizer.

 

[Rick]

Yes lichen not moss.

Yes, from a ratio standpoint the Ca to K ratio is pretty typical for leaf tissue ratios in lots of wild epiphytes.

Dust transfer of Ca, Mg, and K does happen, but the numbers only get (as big as our fert concentrations) when you multiply by hectares and years of area and duration.

Air is 78% N so plants (and lichens) are swimming in it 24/7. So between the lichens (fungi/bluegreen algae colonies) and blue green algae living in mosses, there can be a constant supply of fixed nitrogen getting trickled over to the higher plants in association with them.

 

[Rick]

I don't think the rain events are what releases the nutrients. Sure nutrients leach out with a rain but I think the orchid roots that are in contact with lichen acquire it with dew each night. The nutrients leched out with rainfall are very dilute where dew will have higher nutrient content. But just because the content is higher does not mean the orchid roots are in a large amount of nutrients. An orchid root may be a foot long but only a small part is in contact with a lichen.

Dew transfer is fine too. You need water as the conduit. I don't think its plausible that there are aerosol transfers of gaseous salts. Just keep track of mass balance and overlay with efficiency. The roots are probably in contact with no more than a few grams of lichen material so even if the plant totally consumed the lichen it was in contact with, then the amount of nutrient is already down 0.0001 times the total concentration of a Kg of dry lichen.

If you have a good scale handy then try to estimate the total weight of some of these orchids (roots and all). It would also be cool if you could track some growth rates of these plants. At any given time, the NPKCaMg.....only comes to about 1% of the plants dry weight. And in general plants don't eat 5 lbs of "food" and excrete most of it back out like higher life forms do. So the "need" of these inorganics will be pretty low anyway.

http://www.soils.wisc.edu/extension/pubs/A2448.pdf

Check out table 1. Alfalfa is a very fast growing greedy plant, but the amount of Ca, K, P, and Mg sucked up by a DRY ton (2000lb) of growth only amounts to 100 lb's (5%) of "need". Based on wet weight drop this down to less than 1% in the living plant.

 

[Rick]

Also it seems pretty routine to get 6 tons per acre per annual growing season for alfalfa. That seems super fast compared to orchids on a good day, but it would be cool to compare rates of tissue growth between some of these domesticated crops.

 

[Ray]

Use the materials to create a moist humid air space for the roots. But think of a way to have a constant nutrient supply. It may be that the roots need to be constantly moist so support bacteria, fungi, algae and lichens within or on the spongy root. These organisms may be what supply the nutrients.

That shouldn't be a problem. If the fabric overlaps the raft so that the ends dip down into the water supply (I'm picturing all of this in a tray), the wicking will be sufficient.

 

[gonewild]

Yes lichen not moss.

Yes, from a ratio standpoint the Ca to K ratio is pretty typical for leaf tissue ratios in lots of wild epiphytes.

Yes but the interesting thing is that Lichens get their nutrients from the atmosphere and not decaying leaf litter or rainfall. What is the reason that epiphytes and lichens have the same ratio? is it because that amount is what the lichens have to offer the epiphytes?

Dust transfer of Ca, Mg, and K does happen, but the numbers only get (as big as our fert concentrations) when you multiply by hectares and years of area and duration.

How much dust from the atmosphere will contact an orchid root directly. The majority of the dust must fall with rain and therefore the nutrient content would be in the rainfall. (actually that is a question!)

Air is 78% N so plants (and lichens) are swimming in it 24/7. So between the lichens (fungi/bluegreen algae colonies) and blue green algae living in mosses, there can be a constant supply of fixed nitrogen getting trickled over to the higher plants in association with them.

Orchid roots that are exposed to the air also support bluegreen algae so they may be receiving a lot of N from the atmosphere directly. Lichens make N, P, K and other nutrients available to orchid roots indirectly from the atmosphere. It seems most wild orchid plants I am seeing here have more exposure to lichen and air than they do to leaf litter.

 

[gonewild]

Dew transfer is fine too. You need water as the conduit. I don't think its plausible that there are aerosol transfers of gaseous salts. Just keep track of mass balance and overlay with efficiency. The roots are probably in contact with no more than a few grams of lichen material so even if the plant totally consumed the lichen it was in contact with, then the amount of nutrient is already down 0.0001 times the total concentration of a Kg of dry lichen.

Almost every leaf in the rainforest is covered with some species of lichens so it may be reasonable to think that every dew drop that falls from every leaf contains a nutrient solution. The nutrient supply may be constant as compared to how it is supplied in irrigation water.

If you have a good scale handy then try to estimate the total weight of some of these orchids (roots and all). It would also be cool if you could track some growth rates of these plants.

That is a project for a graduate student!

At any given time, the NPKCaMg.....only comes to about 1% of the plants dry weight. And in general plants don't eat 5 lbs of "food" and excrete most of it back out like higher life forms do. So the "need" of these inorganics will be pretty low anyway.

So why then do most orchid growers need to apply excess nutrients?
It is because other factors are not correct, like moisture on the roots. In nature the plants and roots are never dry at night and growers strive to have them be dry. Perhaps the nutrient uptake happens at night and not so much during the day? The way we grow roots is probably inefficient, In nature most roots grow spaced out and not in a tangled mass like in a pot. Perhaps the roots in a pot have lost their collection surface by being covered by another root?
Your basket culture comes close to letting roots grow naturally and efficiently.

http://www.soils.wisc.edu/extension/pubs/A2448.pdf

Check out table 1. Alfalfa is a very fast growing greedy plant, but the amount of Ca, K, P, and Mg sucked up by a DRY ton (2000lb) of growth only amounts to 100 lb's (5%) of "need". Based on wet weight drop this down to less than 1% in the living plant.

But here you are "forcing" alfalfa to grow fast for a purpose. That relates to forcing Phalaenopsis without regard to long term plant health. And no one cares about long term Alfalfa plant health. Of course even when forcing Alfalfa the nutrient content is a small percent of mass.

 

[gonewild]

That shouldn't be a problem. If the fabric overlaps the raft so that the ends dip down into the water supply (I'm picturing all of this in a tray), the wicking will be sufficient.

Picture thread to show us from the beginning to end please!

 

[gonewild]

Lycaste plant that I referenced above.

This plant is in a area under dense tree cover. But low even cover without many layers. Looking up it was perhaps 50% sky. Water from rainfall would be about half pure rainwater and half with nutrients from tree leaves.
The plant is growing in fallen leaves. Strangely the leaves were in layers separated by the orchid roots. here is a lot of airspace around he roots and the majority of any single root does not contact a leaf but rather spans airspace.

You can see the light colored parts of the roots were not in contact with any leaf or decaying plant matter. Also lot of the litter mass is actually old dead orchid roots fro previous seasons growth.

It was just beginning to bloom with one open flower and many buds.

 

[gonewild]

There was many species growing near the Lycaste.

This Sobraila is growing right beside the Lycaste. The leaf litter has to about as fertile as rainforest litter gets but notice the leaves are still not deep green. I thing the color green misleads people into thinking their plants need more Nitrogen.

Here is a collection of species growing epiphytic on a root/limb a little higher than the Lycaste. These plants have the moss and leaf litter.

Higher up the tree, I don't know what it is but it does have lichens growing on it.

 

[Rick]

So why then do most orchid growers need to apply excess nutrients?

That relates to forcing Phalaenopsis without regard to long term plant health. And no one cares about long term Alfalfa plant health. Of course even when forcing Alfalfa the nutrient content is a small percent of mass.

I don't think that most orchid growers need to apply excess nutrients, but they do out of habit. I've cut back application rates by 95% and getting better growth now than ever. Collectively the hobbyist is lucking out on 90% waste of both materials and time, and not even realizing their growing potential

Actually if you convert the units between the lichen and alfalfa to be the same, then the lichen really only contains about 1/5 the amount of inorganic nutrient per unit mass.

The true agri application of inorganic nutrients (compared to orchid hobby) is quite interesting. In the case of real agri, fertilizer = cost (not profit) so lots of very good math and plant physiology research was done to optimize (not force) the inherent max growth rate of the plant to the amount of nutrient applied. Genetics makes the plants go faster not nutrients. So like race cars, the engines are engineered for torque and HP, but at some point it doesn't make a difference how much gas you give it. It ain't going any faster (and actually looses efficiency at a certain point).

 

[gonewild]

I don't think that most orchid growers need to apply excess nutrients, but they do out of habit. I've cut back application rates by 95% and getting better growth now than ever. Collectively the hobbyist is lucking out on 90% waste of both materials and time, and not even realizing their growing potential

Actually if you convert the units between the lichen and alfalfa to be the same, then the lichen really only contains about 1/5 the amount of inorganic nutrient per unit mass.

The true agri application of inorganic nutrients (compared to orchid hobby) is quite interesting. In the case of real agri, fertilizer = cost (not profit) so lots of very good math and plant physiology research was done to optimize (not force) the inherent max growth rate of the plant to the amount of nutrient applied. Genetics makes the plants go faster not nutrients. So like race cars, the engines are engineered for torque and HP, but at some point it doesn't make a difference how much gas you give it. It ain't going any faster (and actually looses efficiency at a certain point).

I am looking very hard here to find a nutrient rich source for orchids. Something that would justify the commonly used rates and ratios we have used for the last 50 years. I can't find any consistent wide spread source of nutrients to justify the amounts. Instead what I see are consistent supplies that correspond to the low levels in K-lite and what you are know reporting. But what I do see is that nutrients are available in a consistent regular steady supply. It looks like orchid roots may have more access to nutrients at night than during the day based on when the roots are exposed to moist nutrient supplies. Orchid plants and roots are not dry at night in the wild. Since we try to have our plants dry at night how does this effect the nutrient uptake?

 

[NYEric]

I'm not into all the chemistry mumbo jumbo but the photos are killing me! Thanks for sharing.

 

[SlipperFan]

Lance, are you thinking that orchid leaves take up nutrients? Our roots stay wet at night, even though we try to have dry plants by then.

I remember Andy's brother (of Orchids on a Stick) talking to our society. He told us to water in the evening. But his environment (CA) is very different from ours (MI).

 

[SlipperKing]

In the 27 years of growing slippers I don't recall crown rot and 9 out 10 times I water it is at "night". Night, meaning 5-7 PM after work or 3:30- 4 AM before work. I have/had basal rot but that happens because of the condition of the mix not my watering.
In regards to orchids growing only where lichen is found. Isn't it possible that both are growing in the same location because its the best enviornment for both rather then one depending on the other nutrients?