Basic Fertilization Questions

[HiOrcDen]

Originally Posted by Ray

I am a proponent of flooding the potting medium at each watering, as it flushes, saturates, and aerates all in one step. Over winter, when the plants are indoors, I mostly use a heavy spray on the media surface until drainage starts, which is admittedly less thorough.

We really don't know how much of what we apply is actually absorbed, because we don't know the retention of all potting media, we don't know how well solutions are spread around the pot as the water evaporates, and we don't know the contact area of the root system in relation to those. My recommendations are just the culmination of years of growing and observation, using the techniques I employ.

I did a calculation (AKA - "sheer folly") based upon the chemical reactions that fix carbon and the resulting nitrogen and water requirements, based upon an assumption that a plant gains one pound of mass in four years (Phals, maybe?), and if it was 100% absorbed, we could water 1 pint (16 fluid ounces, or about 570 ml) a week using a 55 ppm solution (assuming about 50 of that was N).

Thanks to all for your advice! So in this case, how do you flood the medium? Do you soak the whole pot in a plastic tub, or something along those lines, with the less concentrated solution for fertilizing with every watering? If not, what constitutes flooding?

I would think that at a certain point wood chips, for example, would be totally saturated with the fertilizer solution, which I would think wouldn't harm the plant. I would also imagine, when flooding, then the roots can also become saturated, which would be safer at lower concentration. If I am correct, then would this not make a very thorough flooding with lower strength fertilizer with each watering, more efficient for growth as well as safer for the plant? Just speculating!

[Ray]

Originally Posted by HiOrcDen

Thanks to all for your advice! So in this case, how do you flood the medium? Do you soak the whole pot in a plastic tub, or something along those lines, with the less concentrated solution for fertilizing with every watering? If not, what constitutes flooding?

I would think that at a certain point wood chips, for example, would be totally saturated with the fertilizer solution, which I would think wouldn't harm the plant. I would also imagine, when flooding, then the roots can also become saturated, which would be safer at lower concentration. If I am correct, then would this not make a very thorough flooding with lower strength fertilizer with each watering, more efficient for growth as well as safer for the plant? Just speculating!

I don’t “soak” my plants by submerging the pots, I use a hose with a “water breaker” or “rain head” on the end, so the flow resembles heavy, air-entraining rainfall, and let it get fully flowing through the medium. I think that is probably the best way to do so.

Water is, by far, the most important factor to growth, so I think you are correct that the best thing you can do is find a way, through selection of potting medium and container, to be able to water heavily and often, and yes, with a tiny bit of fertilizer.

Adequate water at the root system is a trigger for the plant to open its stomata for gas exchange, allowing more carbon dioxide intake, which leads to faster carbon fixation - growth. If you grow in a medium that must dry out to avoid suffocating the roots, you are forcing the cycling of that process on and off, which must slow things down.

Granted, this is a very generalized and simplistic description of the “base process”, as plants handle such activity differently, but the concepts are still applicable.

[HiOrcDen]

Apologies, I mistakenly added an unnecessary post, and not sure how to delete it!

---------- Post added at 01:24 AM ---------- Previous post was at 01:00 AM ----------

Originally Posted by Ray

I don’t “soak” my plants by submerging the pots, I use a hose with a “water breaker” or “rain head” on the end, so the flow resembles heavy, air-entraining rainfall, and let it get fully flowing through the medium. I think that is probably the best way to do so.

Water is, by far, the most important factor to growth, so I think you are correct that the best thing you can do is find a way, through selection of potting medium and container, to be able to water heavily and often, and yes, with a tiny bit of fertilizer.

Adequate water at the root system is a trigger for the plant to open its stomata for gas exchange, allowing more carbon dioxide intake, which leads to faster carbon fixation - growth. If you grow in a medium that must dry out to avoid suffocating the roots, you are forcing the cycling of that process on and off, which must slow things down.

Granted, this is a very generalized and simplistic description of the “base process”, as plants handle such activity differently, but the concepts are still applicable.

Thank you for the enlightenment! How do you apply fertilizer when watering with a hose? Do you use the hose attachment that holds and dispenses fertilizer automatically as you water, along with the rain head you mentioned? (maybe both features in one attachment?) and if so what concentration do you place in the attachment? (If it's not too much trouble could you tell me the name of the attachment you use?)

How do you water very small plants, like in 2-3" pots, just shower over them? Also, when you say tiny amounts of fertilizer, is that the 25-50ppm that Estación Seca described?

Again, I truly appreciate all the tips. And sorry for the barrage of questions, I really want to get the right practices down! And you seem to have the right answers lol

btw will check your website for answers too!

[Ray]

Originally Posted by HiOrcDen

How do you apply fertilizer when watering with a hose? Do you use the hose attachment that holds and dispenses fertilizer automatically as you water, along with the rain head you mentioned? (maybe both features in one attachment?)

There are many ways to "skin that cat". When I grew in a greenhouse, I used a metering pump the injected a liquid fertilizer concentrate into the water passing through the hose. I used a Dramm Water Breaker to make it "rain".

Now that I have retired and downsized, and have no greenhouse, when the plants are out on my deck, I use an Ortho Dial-and-Spray hose-end sprayer to add the fertilizer and other additives.

When they are indoors over the winter I use a battery-powered backpack sprayer that also has a wheeled dolly so I can just roll it around. I put everything in that and adjust it for a coarse spray.

and if so what concentration do you place in the attachment? (If it's not too much trouble could you tell me the name of the attachment you use?)

How do you water very small plants, like in 2-3" pots, just shower over them? Also, when you say tiny amounts of fertilizer, is that the 25-50ppm that Estación Seca described?

Again, it varies with the circumstances.

When the fertilizer was injected with the metering pump in the greenhouse, I used 25 ppm N and watered 3-4 times a week. In summer outdoors, here in NC, I have to water frequently, but being more of a hassle to use the hose-end sprayer, I feed weekly at 100 ppm N.

I generally recommend that you think about the frequency of feeding, then sum up the concentrations applied, making the total somewhere in between 75 and 125 ppm N.

Under my "equal abuse" policy, all plants are treated the same.

[WaterWitchin]

"Equal abuse policy." That's the policy I follow here as well. Well-stated.

[Roberta]

For a small collection, a 2 gallon pump sprayer is handy. You can fill with your fertilizer solution (or plain wanter) and easily carry it around. that is my "indoor hose" and also how I used to fertilize outside (long after my collection could be considered "small".)

[Orchid Whisperer]

Any water-soluble fertilizer that provides N, P, and K is fine. If it also provides Ca, Mg, and trace elements, even better (if your water supply does not have much of these). More frequent but dilute applications seems better than infrequent strong applications.

An orchid does not really care whether nitrate-N, ammonia-N, K, or P comes from an organic fertilizer, or a fertilizer that might be considered "inorganic". Also, most orchids don't need much fertilizer, as others have said. Wild orchids living in trees get their nutrients from animal wastes, plant exudates, plant and animal debris trapped in the orchid's roots, really anything that comes along. Some of the nitrogen actually comes from rainfall itself.

Slow-release can be OK, and I know people that have used it. The fertilizer is in small spherical capsules called"prills". If you go this route, shop carefully for types meant to be very slow release, for epiphytes. A friend that used slow release has cautioned that some cheaper slow release fertilizers can "dump" their remaining fertilizer all at once under certain conditions (not desirable). I don't recall the conditions that causes that dumping, but frankly, it was a reason I have stayed away from slow-release fertilizers for orchids.

[Roberta]

I use slow-release ferilizer in addition to my regular regimen for particularly rapid-growing, "hungry" types... mostly Cymbidiums and Catasetinae, in the spring. Contrary to usual perception, they don't leach their payload so much in response to water as response to temperature. So a hot spell can produce a burst. Which is OK for those fast-growing types, they are likely to also increase their growth in hot weather. But it's likely to be too much for most orchids. In general, it's better to under-fertilize than over-fertilize. Too little and the plant may not grow to its full potential. Too much and you can burn leaves and roots, damage the plant.

[WaterWitchin]

I use just as Roberta says… plants like Cymbs, Ctsm, that can just drink it down with the rapid growth cycle. For most… weak and infrequently.

[HiOrcDen]

Originally Posted by Ray

There are many ways to "skin that cat". When I grew in a greenhouse, I used a metering pump the injected a liquid fertilizer concentrate into the water passing through the hose. I used a Dramm Water Breaker to make it "rain".

Now that I have retired and downsized, and have no greenhouse, when the plants are out on my deck, I use an Ortho Dial-and-Spray hose-end sprayer to add the fertilizer and other additives.

When they are indoors over the winter I use a battery-powered backpack sprayer that also has a wheeled dolly so I can just roll it around. I put everything in that and adjust it for a coarse spray.Again, it varies with the circumstances.

When the fertilizer was injected with the metering pump in the greenhouse, I used 25 ppm N and watered 3-4 times a week. In summer outdoors, here in NC, I have to water frequently, but being more of a hassle to use the hose-end sprayer, I feed weekly at 100 ppm N.

I generally recommend that you think about the frequency of feeding, then sum up the concentrations applied, making the total somewhere in between 75 and 125 ppm N.

Under my "equal abuse" policy, all plants are treated the same.

I'm curious, why can't you use a metering pump outdoors? Forgive me, I am not familiar with their usage.

So is the 75-125 ppm N the concentration in the dial sprayer, and not what comes out of the hose? So this doesn't to some degree diminish the advantage of watering frequently at very low concentration?

Also, forgive these two basic questions... When do you know you have watered thoroughly enough, and do you wait until substrate is nearly, or fully dry (depending on species?) to water?

Finally, what is a good way to acquire the kind of knowledge many of you have of species. I know it is recommended to research the various habitats. But are there any particular books, or websites, like Orchid Wiz, to study for this knowledge?

---------- Post added at 10:53 PM ---------- Previous post was at 10:46 PM ----------

Originally Posted by Roberta

For a small collection, a 2 gallon pump sprayer is handy. You can fill with your fertilizer solution (or plain wanter) and easily carry it around. that is my "indoor hose" and also how I used to fertilize outside (long after my collection could be considered "small".)

I have a 3 gallon pump sprayer for my Bonsai. I already have 7 Orchids, got a bit carried away lol, but they are doing well, luckily. So I imagine another 2 or 3 gallon sprayer would work for awhile?