Advice on Fertilizing?
 

Hi, beginner here! Lots of questions on this, but I've gotten a few new orchids and just want to know if I'm doing things right. At the moment i got 5 pals and 1 new Miltonia 'Sunset'.
At the moment I use Miracle Gro Water-Soluble Orchid Food on my pals along with Miracle Gro Coarseblend Orchid Potting Mix. Food Ratio: 1/4tsp: 1 gal.
1. The food suggests using it every 2 weeks but in my opinion that seems persistent in fertilizing, especially as it gets colder. Do I continue using it at this rate or start using it once or twice a month depending on current temps?
2.Do I continue using this fertilizer while my orchids are in bloom? Some say not to & some say to continue.
3.(if i stop, do i begin again after the flowers fall off?)
Can I use the same Orchid food I use on my phals on my Miltonia?
4.+Completely my fault but I had left 3 of my phal orchids in the sun for a too long resulting for them to, unfortunately, suddenly drop their flowers. Do I continue to use the food/fertilizer on them like normal to continue growth/rehabilitation?

Sorry for all the questions! I have many more of them to come, I just want to keep all of my plants happy & healthy :)

I fertilize my Phalaenopsis and my Trader Joe’s Miltonia Sunset look alike year round. I use about half the recommended fertilizer dose every other week. These guys are always growing something (leaves, roots, or flowers)

I was gifted some Miracle Gro orchid mix and it had a lot of fine particles and slow release fertilizer granules already incorporated. I’ve used a 50:50 mix of the Miracle Gro mix and BetterGro coarse mix for my Miltoniopsis successfully but the Oncidium type I tried it on wasn’t happy. I’m not sure how well Phalaenopsis would do in it. I’ve gone ahead and fertilized normally despite the granules and the Miltoniopsis are happy. Maybe the Miltonia Sunset will like it?

I use MSU fertilizer. I think I remember reading that the Miracle Gro had nitrogen as urea and it wasn’t available to orchids, but I could be totally wrong. I also had some Miracle Gro fertilizer when I started out and I used it on my outdoor orchids with no ill effects.

I have my Miltonia Sunset in fine bark and I try to water whenever the substrate approaches dryness. It’s a really tough vigorous plant, but gets a lot of cold damage if subjected to prolonged exposure to temperatures below 60. So far, it is my most cold intolerant orchid (my Phalaenopsis have more tolerance than it does).

Thank you for the advice on the Miltonia, I’ll start fertilizing as you said aswell as going out for the substrates as listed. How do you know when to repot your Miltonia? The Miltonia I purchased from Trader Joe’s has very fine soil, and comparing to your mix is a drastic difference.

Miltonia Substrate pics

1/4 to 1/3 of their recommended dosage is what I've read from some sources and word of mouth. I've been following this scheme all along.

I just use fertiliser once a month. Eg. beginning of each month... I apply fertiliser. Then use regular water for 2 weeks. Then at the middle of the month, I apply calcium/magnesium solution. Then regular water for 2 weeks. Then we reach the next month... so back to fertiliser again - once. But, if any solution is left-over on the day of application... then I just top-up the left-over solution with water and just water with this even weaker solution.... so as not to waste anything.

This scheme has worked excellently for my amateur hobby orchid growing.... for years. I'm fine with the scheme - as I have orchids sitting outdoors in plastic pots (in lava rock media) that have never been manually fertilised --- they probably get natural fertiliser with bugs/insects etc in their pots. Those orchids required no maintainence for a few decades.... watered by automatic sprinkler along with the lawn and shrubs. These orchids are big and strong.... flowering every year. So - for my other orchids, fertilising once a month has been just fine.

Ask a dozen growers about feeding and you'll get at least 13 opinions!

Personally, I think it pays to think of fertilizing like providing meals for yourself - it is healthier to eat frequent, small meals than it is to gorge oneself every few days. Likewise, if you think about orchids in nature, they get "fed" a minuscule amount every time the rain starts falling, plus whatever microbes provide.

How much fertilizer you use should be primarily controlled by the frequency of application, but I think a total of about 100 ppm N applied over a week is a good target.

When I had a greenhouse with close to 1000 plants, if fed at every watering by using a metering pump to add it to my water supply at 25 ppm N. In the summer, they got 3-4 feedings a week, but in winter when the weather was gray, I sometime only watered once a week, but as the plants weren't doing much, that low amount was fine.

Now that I have downsized and only have a couple of dozen plants, I feed one time per week year-round @ 100 ppm N.

Don't let the units scare you: divide 8 by the %N on your fertilizer label. The result is the teaspoons per gallon for 100 ppm N.

If I've got the right formula, your fertilizer is a 30-10-10, so 8/30=0.2667 tsp/gal. If you used 1/4, you'd be fine.

Orchids can use urea-based nitrogen, but root uptake is reduced compared to nitrate and ammonium sources.

Thank you for that info, I’ll be sure to follow the measurements you guy’s have suggested & how often you would use it, without that info I’d most likely be going all over the place ahah; And, would I continue to fertilize my sun damaged phals like normal or allow them to take a break? I know that they need more enrgy to heal themselves.

Regarding repotting the Miltonia, I’ve tried everything and I can not keep roots alive in that fine soil like substrate (ProMix). I now repot any plants I buy in it as soon as I get them home. I give them a quick soak, spray as much of the old mix out with the hose as possible, and pot them up. Don’t worry about getting every little bit out and try to manipulate the roots as little as possible. If you’re gentle with the roots, the plants don’t miss a beat and keep their flowers. Every time I’ve waited until the plant finished blooming, I was left with almost 100% dead roots and a plant that took at least a year to recover.

I’ve also learned with these: do not cut the roots. Even the ones that seem dead. I think the inner root is still functional even when the outer envelope is squishy. The plants where I’ve left even seemingly dead roots intact don’t blast their flowers or show any signs of stress following repotting. Those that I’ve tried to clean up dead roots on, however, do often blast at least some flowers.

None of these plants really take a break. The sun damaged Phals are going to want to push out new leaves and heal what damage they can: I’d just fertilize as usual with whatever formulation / regime you decide to adopt.

The fuel plants need are the sugars they produce from light and the building blocks in air, water, and only a tiny bit of fertilizer. When a plant is adding tissue (growing), it uses them all as building blocks.

In my opinion, plants need a very small but steady supply of food. A horticulture professor friend once did the chemical process calculations, and for any plant to add a pound of new tissue, it must absorb and process about 25 gallons of water, but only 5 grams of N+P+K.

The fertiliser in say bark or rock media is likely going to be hanging around for a while.

So applying fertiliser once a month doesn't mean that the fertiliser is gone (disappeared) after just 1 day. With a suitable dosage - even if relatively infrequent (eg. once a month) - the orchid can have enough fertiliser to grow very well, year in and year out.

For optimising growth rate etc, some research needs to be done to determine a schedule and dosage (taking into account growing environment etc) that allows for good growth rate. This would be the scientific approach - which is very good.

Maybe every few months or so - or perhaps even once a year, a serious flushing of the media with water can be beneficial - to bring down accumulated build up of whatever is in the pot (salts etc).

Thank you all so much,
So for summary this is what I have planned:
Fertilize using 1/4th solution 1-2 times a month based on temperature.
Water regularly every week or to when it gets too dry.
I was wondering if I could use 50:50 MiracleGro Mix & Spagnum moss? It’s quite dry here & I know they need quite a bit of humidity.

Not "1/4 solution" (I assume you mean the recommended strength on the label), but 1/4 teaspoon of that formula per gallon, applied weekly.

If, somewhere down the road, you buy a different formula, you should adjust your dosing accordingly. For example, if you were to use K-Lite, a 12-1-1 formula, then you'd use 8/12= 3/4 teaspoon per gallon, giving you approximately the same amount of nitrogen per gallon as 1/4 teaspoon of your current formula.

Yeah sorry for the miswording, will do!

Just quoting myself, as I thought that I should at least attach some photos of examples of some of my orchids that have never been manually fertilised. Never once manually fertilised for a few decades.

They are not watered by hand as well. These ones get their water either from rain, or from automatic lawn sprinkler (which waters the shrubs and the lawn grass) ---- not the small sprinklers --- but proper lawn sprinkler.

The fan leaf orchids are Angraecum eburneum. And the dendrobium is Dendrobium discolor. These two sorts of plants - once sunhardened - can handle a real beating from intense direct sun.

Also, hiding on the mid-right-hand-side of the Dendrobium discolor photo is a rather small size Dendrobium moschatum, which also gets its water from lawn sprinkler. No manually applied fertiliser is given to this one. The sprinkler wets its leaves and all. Everything dries out fairly quickly. Good air circulation.

In the photos, in general, the plants grew up all the same - and the roots just go everywhere, even onto the ground. The plants do not rot. Showed no signs of disease/fungal/bacterial activity.

For certain years (not every year), when there is a big spike in sun intensity - some leaves do get burned. But no problem.

The growing media for all of these orchids in the photos is lava rock ..... aka scoria ... (locally variety is known as quincan gravel, pronounced 'kwing-kun' gravel). The media has never been renewed (ie. never needed to take the plant out and put in new media). The media has never been flushed with water.

For my other orchids, where I do apply monthly fertiliser, I will occasionally flush the pots with water..... like once a year. This doesn't mean that other people should do once a year - because this all depends on how much fertiliser they use, and their growing media used, and growing method, watering method, watering schedule etc.

Also attached are relatively recent photos (2019) of flowers from those particular plants (that have never been manually fertilised - not even automatically fertilised - for a few decades). I have a feeling that insect activity inside the pot might provide some fertiliser to these orchids, and the roots had even grown long enough to touch the floor (ground) - which then possibly forms an extra source of 'natural' fertiliser intake.

Wow! They’re very beautiful! Wish I could do that here!

I wish that you could or can too! What I find quite excellent is that you and other very keen growers do remarkable work with growing your orchids with various encountered constraints. We can all learn from your shared experiences in this orchidboard forum.

Like Ray I fertilize at every watering. I use a combination of Peters commercial (not orchid) fertilizers according to season and adopt the regime of "weakly weekly" which gives excellent results.
I understand the need to dilute ordinary garden fertilizers to maybe 1/2 or 1/4 strength but have never understood why people do that with specific orchid fertilizers. Much research has gone into those special potions so surely the instructions on the bottle should be followed.

My logic for using very diluted fertilizer is because the plants have evolved receiving solutions (rain) of VERY low solids contents and electrical conductivity, very frequently, so it makes sense to follow that in cultivation.

The ingredients used in "orchid" fertilizers and general-purpose garden fertilizers are identical. About the only difference is the label. Don't forget, a fertilizer manufacturer's goal is to sell fertilizer, not help you grow better plants. The "research" that goes into designing a formula is "what did the customer ask for?" or "can we make a generic formula that will suffice for more of our customers?", as switching is costly in a manufacturing operation.

About the only formulas I'm familiar with that were backed by university research are Miracle Gro Mir-Acid by Dr. O. Wesley Davidson at Rutgers 70-80 years ago, those originated at Michigan State University about 15 years ago, and K-Lite, derived from an MSU formula by one of their researchers. All were designed "on paper", with the mineral ratios based upon research into the needs of plants with some orchid-related assumptions, and in all cases the evaluation was the same: "We tried it and it worked".

I think of fertilizer as more similar to."vitamin supplements" (if you are comparing human vs plant nutrition) rather than "food". The basic building blocks come from photosynthesis. Fertilizer components are available (in nature) to orchids in low doses, through rainfall and runoff from tree leaves, branches and trunks. We provide fertilizer (in low quantities) because plants grown in the home may not receive enough nutrients in the right proportions for optimal growth.

As long as you are providing a dilute fertilizer that provides N,P, and K, you are probably providing what orchids will need, assuming some trace elements are provided by your tap water. The advice used to be, provide fertilizer "weakly, weekly" but "weakly, monthly" is probably sufficient, "weakly" being something more dilute than the fertilizer package recommends (try 1/4 strength). If you want to go with really dilute fertilizer, you could fertilize more frequently.

Aliceinwl, the advice on urea N is based on old information. Orchids utilize urea N with no problems (there has been published research on this). That advice is based in part on the fact that long ago, urea fertilizers contained a substance called biuret, which can harm plants. With better manufacturing, biuret is no longer a problem.

Sorry for the late reply, been busy.
I’d love to grow my orchids outdoors but unfortunately AZ’s got some extreme temperatures & crazy weather, absolutely love your orchids though! I’ll dilute the fertilizer and use it weekly instead just to see how that works, thank you for the advice! & thank you for letting me know about the Urea N. I still thought that orchids couldn’t process that properly. Along with having a similar formula to other general fertilizers, I thought they would definetly be different, I will definitely keep that noted. Another question, sorry, what medium would work for my Miltonia? I heard that Miltoniopsos and Miltonias have different care setups, wonderinf if that also included mediums & repotting. Would 50:50 MiracleGro coarse mix & Spagnum moss work? Feel free to lettimg me know anything I need to change or add to the medium, or also what you guy’s have used successfully! Thank you for the help :)