Fertilizers make me confused!!!

[Ray]

Addressing Mimi's original post, yes you are correct about ratios: 1 teaspoon of a 10-10-10 has the same nutrient content as 1/2 teaspoon of a 20-20-20 formula.

I would strongly urge, however, that you and every other grower get rid of the "half strength" or "quarter of the recommended strength" way of looking at fertilizing.

For one, manufacturers are trying to sell you fertilizer, not help you grow your plants better. Second, most know nothing about orchids. Given those two factors, why would you trust their recommendation?.

As I said previously, whether you use a 7-9-5, a 30-10-10, 15-30-15, or a 12-1-1 formula is, in my opinion, far less important than the mass of nutrients applied. Using a human analogy, we probably are more concerned about calories than we are about the ratios of proteins, carbohydrates, and fats. Yes, they are important, but the amount of food you eat plays a much bigger role in your overall health.

I really think the best bet is to select a formula you want to use, then use it regularly and consistently at a relatively low dose. Don't forget that the amount (dose) used is directly connected to the frequency of application!

Stick with that for a year or more - plants do not react to changes quickly - and then consider changing the formula if you think there's room for improvement - and have some knowledge of what might move you in that direction.

[bil]

Originally Posted by Orchid Whisperer

Hi bil

I'm not saying K-lite, or its use, is stupid. In fact, I said if you are happy with it, why change.

I'll post a link to just one thread as a starting point, there are some opinions early in the thread regarding symptoms attributed to low K fertilizer. [url]http://www.slippertalk.com/forum/showthread.php?t=37714&highlight=K-lite[/URL . Fair warning, some of the opinions in the thread were argumentative, on both sides of the issue. Read if you care to, make your own conclusions.

What I would like to see is a true, controlled scientific experiment (a trial) that evaluates K-lite vs. other fertilizers. The only study I have seen that comes close was a study of potted Dendrobiums that varied the amount of the 3 major plant nutrients one at a time. Lower K produced lower flower number. I don't think any of the fertilizers qualified as true K-lite, though.

You misunderstand me. It's a humorous phrase. "If it's stupid, and it works, then it isn't stupid".

Thanks for posting that link. Very interesting, even if reading it all in one sitting made my head spin.

The basic summation of all that seems to be this.
"Not everything works for everybody".
Quelle surprise!
I shall continue to use it as Ray does, at low levels, at every watering, but I will keep an eye out for the potential problems.
I was hugely amused by the one guy who was knocking it. If I got it right, he uses an extremely high tech enhanced CO2 with all knobs, bells and whistles. How is that relevant to the average grower?

[PaphMadMan]

Fertilizers are a complex topic, but really can be very simple. Only you can decide how complicated you want to make it. Remember that no fertlizer can make up for poor light, low humidity, bad water quality, wrong temperatures, old stale media, bad watering practices, etc. For most hobby growers, especially windowsill growers, fertilizer will almost never be the thing that limits your success if you keep it simple but consistent. This is probably going to get me flaming responses and hate mail, but here goes.

If you use media that is mostly organic (bark, moss, etc, not inert pellets of whatever) and repot every year or 2, then use any water soluble fertilizer with micronutrients that is intended for general orchid use or indoor flowering plants. Use it at 1/4 the strength recommended on the package for 3 out of 4 waterings when your plants are in active growth, 1 out of 4 waterings when not in active growth, or not at all for plants that have true dormancy.

If you have perfected every other aspect of culture, then it is worth looking more closely at fertilizer. If it interests you, go ahead and make it complex, but it is almost certainly not the limiting factor for your plants.

[Orchid Whisperer]

PaphMadMan, you won't get any flames from me! Very solid advice.

The only difference I make, in practice, is to maybe fertilize less often than you stated. I do pay more attention to the balance between the three NPK nutrients than I used to.

[D_novice]

If I can revive an old post - and I think this may be my 1st or 2nd post in this forum - I recently purchased a pelleted slow-release fertilizer from a well known american orchid supply catalog / website. I believe it is an MSU formula that is low P, 11-2-12 (so a subject not yet broached on this thread).
I also recently purchased a small bottle of Dyna-Gro Bloom, which is high phosphorus, 3-12-11!
I wrote to the catalog people, and they promptly wrote me back saying "this is all experimental, some people believe orchids don't need much phosphorus, while some believe that phosphorus is essential to blooming".
Given that the take home message proffered by the experts who've weighed in on this thread is "fertilization is a low priority in orchid cultivation for most non-expert growers", this isn't surprising - but it appears no one actually knows what orchids need! If high P does encourage blooming, presumably low P discourages it! (I think).

Anyway, I am going to read the linked article, but I find it curious that something fairly basic like this is so unsettled.

One other thing that I haven't seen people discuss when addressing this subject. Couldn't - in nature - a leaf or an insect or animal droppings or any other number of things become lodged in an epiphytes roots or leaves or the tree bark to which it is attached, and slowly break down over time, feeding the orchid?

Anyway, my primary question is about the P in fertilizers. thanks

[Orchid Whisperer]

Hi D_novice

You can read and/or download an article on fertilizer ratios here: Nitrogen, Phosphorus, and Potassium Requirements for Optimizing Growth and Flowering of the Nobile Dendrobium as a Potted Orchid. Note the links at the upper right for downloading the whole article. Long story short, the article indicates that P is used less by orchids than N and K.

I do use a fertilizer with N and K low relative to P at times, an 11-35-15 formula made by Dynagro for orchids. It is marketed as a "bloom booster". I think what the fertilizer does to promote blooming is reduce the N provided at bloom time.

Best thing you can do to promote good flowering is to not use too much fertilizer. A friend that grows excellent Cattleyas says he almost never uses fertilizer. He grows in bark in case you were wondering.

[bil]

Originally Posted by D_novice

If I can revive an old post - and I think this may be my 1st or 2nd post in this forum - I recently purchased a pelleted slow-release fertilizer from a well known american orchid supply catalog / website. I believe it is an MSU formula that is low P, 11-2-12 (so a subject not yet broached on this thread).
I also recently purchased a small bottle of Dyna-Gro Bloom, which is high phosphorus, 3-12-11!
I wrote to the catalog people, and they promptly wrote me back saying "this is all experimental, some people believe orchids don't need much phosphorus, while some believe that phosphorus is essential to blooming".
Given that the take home message proffered by the experts who've weighed in on this thread is "fertilization is a low priority in orchid cultivation for most non-expert growers", this isn't surprising - but it appears no one actually knows what orchids need! If high P does encourage blooming, presumably low P discourages it! (I think).

Anyway, I am going to read the linked article, but I find it curious that something fairly basic like this is so unsettled.

One other thing that I haven't seen people discuss when addressing this subject. Couldn't - in nature - a leaf or an insect or animal droppings or any other number of things become lodged in an epiphytes roots or leaves or the tree bark to which it is attached, and slowly break down over time, feeding the orchid?

Anyway, my primary question is about the P in fertilizers. thanks

1. There is no conflict between the two ideas that phosphorus is essential, but that the plant only needs low levels.

2. Unsettled? It's a variable in a sea of variables. Of course one size won't fit all.

3. Leaves and the odd bird turd. Yes that adds nuitrition, but leaves fibrous residues that choke the airways into the potting medium.
Plus it upsets the balance of fertiliser. A lot of us try and keep fertiliser levels fairly precise, so what's the point in adding random amounts.

4. You need to find what works for you.

[mimigirl]

D_novice, yes it is confusing, isn't it? Just when you think a response makes sense, boom!, a conflicting response. You know what? They are all correct! I have had chids for a few years now and trying hard to get it right. But I guess the only right answer is the one that works for us. I have two of the same genus sitting next to each other and treat both the same. And each one gives different results. Not only do conditions vary from grower to grower, but the plants themselves vary. So the opinions we get are reflections of what works for the person with the answer. Like Ray said, pick one and stick with it for a year. Any fertilizer is better than none. Join some orchid lovers facebook pages and really see the differences in advice. IMHO it is pretty much a crap shoot. You just need to read a lot, do your best and have patience. Try to sort through the info to see what works for your comfort zone. I hate mounts because I underwater. Like PaphMadMan said - fertilizer wont make up for other poor conditions. Me? I just ordered a light meter. (PS: AOS has a fb page. Let me know if you want other ones)

[Orchid Whisperer]

Originally Posted by bil

1. There is no conflict between the two ideas that phosphorus is essential, but that the plant only needs low levels.

2. Unsettled? It's a variable in a sea of variables. Of course one size won't fit all.

3. Leaves and the odd bird turd. Yes that adds nuitrition, but leaves fibrous residues that choke the airways into the potting medium.
Plus it upsets the balance of fertiliser. A lot of us try and keep fertiliser levels fairly precise, so what's the point in adding random amounts.

4. You need to find what works for you.

bil, I think you hit the nail on the head.

I would add that what is provided in nature (the random decaying leaf, or chance bird poop) is what the plants evolved to use, but it may not match optimal plant nutrition. When we are growing in our homes, greenhouses, yards, etc., we aim to give the plants what we THINK they will need to "be at their best". We are sort of pampering them like prized show dogs so that they perform better, not necessarily to duplicate nature 100%. As a comparison, if you provided a garden tomato plant with only the nutrition that a wild tomato ancestor might receive, you might not be pleased with the yield or quality that you would get.

As research is performed, or as we develop a knowledge base from decades of experience from hobbyists and professional growers, the idea of what we need to provide to keep plants at their best evolves. In the meantime, as bil stated, each grower uses what works best for them.

[D_novice]

Thank you!

By far the best information I've encountered anywhere on this topic (reached through the page referenced in an earlier post, from the St Augustine Orchid Society) is Rick Lockwood's "What Do Orchids Eat?"


Dr. Lockwood (he must be a Ph.D.) has actually applied science and done research to reach informed conclusions. Some people might not care, since his conclusion is still fertilize lightly (and don't use too much K, and do use some Mg and Ca, and this result may only be applicable to Paphs) but it is wonderful to read some actual evidence on this rather than just "accepted wisdom". This is, after all, a discussion of biochemistry and botany.

---------- Post added at 10:59 AM ---------- Previous post was at 10:54 AM ----------

An afterthought here - there is an interesting dynamic between spoiling a plant to optimize it's health and growth, and stressing it to make it stronger (healthier). I won't go on and on, but stress (for instance, coldness and dryness and possibly short-term lack of nutrients) may be as important as ideal conditions.

It's interesting, and bil your point about variables is spot on - since there are nearly infinite ones, including in plants sitting right next to one another (assuming they're not clones).