Fertilizer Change During Flower Spike

[Ray]

Originally Posted by Bloomer001

I'm going to try a seaweed extract next Spring through Fall when root development starts again (KelpMax, Clean Kelp, etc.).

Some kelp extracts are designed more to stimulate root growth. Others, like Kelpak (formerly retailed as KelpMax) is more of a "biostimulant IV" that affects everything.

[I want the plant to focus on spiking and budding now, so going to forgo hormones that trigger root production for the moment.

Kelpak is not a hormone root stimulant.

I like your Ca and Mg formulas - I will experiment with these.

If you are using NYC water, you must supplement them.

And I will get a pH tester to take a closer look at that, and treat water to get an optimum pH level (likely pH down).

The pH of your applied solutions have little-, to no effect on the rhizosphere pH. Read: Orchids and pH

Based on my limited experiments, I think higher nitrogen is key for leaf, root & spike growth. Everytime I dosed the Miracle Grow with 24 nitrogen the leaves, roots & spikes took off (it is very noticeable.) The MSU pellet formula that I use has less nitrogen at 13 N. So that tells me the higher N in the Miracle Grow is making things happen (at least for leaves, roots and spikes.) I don't know if high N is as critical for budding and flowers. (Ray's website says it is.)

You're making several mistakes here.

1) Don't equate formula with concentration. One teaspoon of a 30-10-10 formula and 2 teaspoons of a 15-5-5 formula provide the identical level of nutrition and the same ratios.

Nitrogen is, by far, the most important nutrient. About 99% of the dry content of a plant is C, O, H, (from air and water) and N (from fertilizer), about 1% is P, K, Mg, Ca, and S, combined, and the remaining fraction of a percent is everything else, so if you control your feeding by nitrogen, adjusting based upon the formulas' content, you're fine.

2)No where does my website say higher nitrogen is critical for budding and flowers. The right level is important. All the mineral elements are needed for the plant to grow all tissues. The fact that some tissues have differing mineral concentrations to others does not mean that adding those will specifically cause the plant to grow those tissues.

Plants basically have three priorities - maintenance (staying alive), adding tissue (growth), and reproduction (flowering). Through the course of water, air, mineral and photon uptake, they undertake a variety of chemical processes that create and array of chemical reserves. Your cultural conditions greatly determine the rates of creation and consumption. Poor and the plant cannot create enough to sustain itself. "Enough" and it may stay alive but not grow. "Additional" provides more opportunities.

First and foremost, they will apply those reserves to staying alive. If the production of the reserves exceed the maintenance demand, the plant will expend them on adding tissue. If the production fare exceeds the total demand, it may expend them on attempting reproduction. What the plant does is not determined by the mineral ratios to which it is exposed, they are controlled by hormonal signals and triggers that are significantly culture dependent.

Focus on culture and wetering, not nutrient ratios. For any plant to gain one pound in mass, it must chemically process about 5 grams of fertilizer and 200 pounds of water. As most plants lose 95% or more of their absorbed water through transpiration suggests that the amount of water absorbed for that pound need to be on the order of 4000 pounds to the 5 grams of nutrients.

[Bloomer001]

I did some more research and I was definitely wrong about adding more Phosphorous during spiking, bulbing and/or flowering. See Exs. 1-2. University level studies show that the correct levels of nitrogen are key to all phases of growth - including flowering. See Ex. 3. And that in order to affect flowering, these levels need to be in the plant during the growing season - well before spiking. Id.

As you suggest, Calcium and Magnesium are critical for all phases of growth. This is well supported by the literature. See Ex. 5. In addition, articles suggest that it may be worth considering water and substrate characteristics to dial in fert ratios. See Exs. 6-7. As you suggest, it's notable that pH in the substrate (rhizosphere pH) can be very different than the pH used when watering. The type of substrate affects pH greatly, e.g. moss makes the substrate very acidic. See Ex. 7. So I need to measure the pH in the pot, before the watering can. I can then dial things in.

I'm interested in the K-Lite fert you offer on your site. The nitrogen ratios seem to be supported by the science and research articles. I will also look into the Kelpak biostimulant on your site. I may end up getting the Optimum Growth Package you offer.

Thank you for your thoughtful comments and suggestions.

[buzzlightyear]

Originally Posted by Bloomer001

I did some more research and I was definitely wrong about adding more Phosphorous during spiking, bulbing and/or flowering.

I agree.

However when it comes to the other nutrients it is far harder to get the right answer. Ray's website is one opinion. But it seems to be very popular on this forum. In fact I'd go so far as to say it seems to be the only valid opinion on this forum when it comes to growing orchids.

I've already mentioned I do not follow Ray's methods.

According to my research nitrogen is indeed the most important nutrient, without nitrogen, plants will not survive. So that makes it important.
What this does not mean is that it need to be fed in the highest quantity at all times. That is not what it means...

That is what I disagree with a lot.

In fact according to my research too much nitrogen will cause stem rot and fusarium. Excessive nitrogen locks out calcium and potassium. This can cause calcium deficiencies.

So what is excessive? Well in order to determine that you compare how much potassium and how much calcium and how much nitrogen you are feeding.

So if you are using a balanced 20-20-20 fertilizer then you are not feeding excessive N because they are all the same strength. If one uses tap water it will contain enough calcium. Rain water will need added calcium added.

So what is excessive? Well it's kind of self explanatory and highly controversial on here based on my research. The opposite of balanced basically. But I know I am in the minority here and it would be like turning up to a republican rally wearing a democrat shirt. I get it. But reseaching these things is important to me. Everyone can argue that nitogen is important and I am not disputing that but it shoud be used in the right quantity.

According to my research, it should not be excessive.

Here is a good scientific article I have been following myself:

Potassium_Nutrition_Affects_Phalaenopsis_Growth_an d_Flowering

[MateoinLosAngeles]

Originally Posted by buzzlightyear

So if you are using a balanced 20-20-20 fertilizer then you are not feeding excessive N because they are all the same strength. If one uses tap water it will contain enough calcium. Rain water will need added calcium added.

I think you're confusing fertilizer composition with solution concentrations. If you feed 1/2 tsp/gal of a 20-20-20 fertilizer, you would give the same amount of nitrogen as if you fed 1.5 tsp/gal of Orchid Pro (7-8-6). So using a fertilizer with a higher N number doesn't mean you're feeding more nitrogen unless, of course, you also increase the amount in solution.

This is to say that the fertilizer you use doesn't really matter, what mattes is how much of it you put in your feeding solution. I personally choose my fertilizer based on how it changes the pH of the water and its ability to dissolve.

To clarify, the reasoning for lower K feeding is based on research showing orchids may have an adaptation to "hog on to K" which allows them to survive in environments with low potassium availability, yet showing sufficient levels in tissue analysis. Thus the reduction of K feeding is aimed to avoid cumulative potassium toxicity over several years, not based on the results of one season.

As you pointed out, excess N seems to be correlated with higher incidence of rot. Thus why I personally fertilize at only 25 ppm N per watering.