Fertilizing - How, What, & When

[sandra]

I'm getting a little mixed up with all the info regarding fertilizers. When?, for which kind of orchids (all?), how much? and does all that make a difference depending on what you're growing the orchids in?

Does the following sound right (for growing in the northern hemisphere)?

April through June - high nitrogen formula (e.g., 30-10-10) weakly, weekly
July through September - bloom booster (e.g., 10-30-20) weakly, weekly
October through March - reduce fertilizing to once/month (bloom booster)

OR, a balanced fertilizer (20-20-20), weekly?

Realizing that growing in bark, a high nitrogen fertilizer would be recommended over a balanced one, correct? Alternating between high nitrogen and high phosphorous for orchids in bark is a recommendation over a balanced fertilizer?

AND what if your growing medium is other than bark such as Dyna-rok or Hydroton which contains nothing organic? Is a weekly maintenance of a balanced fertilizer recommended with a flush every 4th watering (using no seasonal, alternating schedule)?

Also, which orchids is it advised to stop fertilizing during winter? I know Dend. Nobiles but, any others?

[articuno75]

Thank you for asking this! I have not a clue on fertilizers and to the point that I'd rather not use them just cause of the fact of me not knowing the proper use. I'm afraid I'd burn up the plant or do some major damage. Help with the basics is much needed here!

[kmarch]

There are different schools of thought on fertilizing.

1) Some take a calendar approach like you've outlined. They set up a seasonal schedule like yours and pretty much give the same fertilizing regimen to all of their plants (all genera).

2) Some go by the growth habits and cycles of the plants (for example someone may fertilize their Paphs year round wiht a weak balanced fertilizer but hit their cymbids hard wiht high nitro in spring and summer and stop altogether in Autumn).

3) Some (like me) don't fertilize.

There are different methods of supplying the fert:
1) through regular watering - for examle "weakly, weekly" where the fert is used fairly dilute (small likelihood of burn) on a regular basis,

2) through mix addatives - either organic material like peat or leaves or a slow release fertilizer like Osmocote,

3) through a foliar spray - sprayed on the leaves and absorbed through them.

Different growers will use different schedules as well as different methods, and even different fertilizers. The bottom line is that the "right" method is the one that works best given your plants, your habits, your location and cultural conditions. The reason fertilizing is so confusing for some is because some of us have found what works best for us and then (probably unintentionally) talk as if this is the "correct" way of doing it. Sometimes what works best for grower A does not work best for grower B so then you have people giving conflicting recommendations.

Therefore, I would recommend trying something I did when I first started growing orchids:

1) First look at the advice given on reputable culture sheets like those provided by the AOS (www.aos.org). These will give you some info specific to a particular genus. For example would you fertilize a orchid that grows and blooms in distinct seasonal cycles the same or differently than one that comes from a tropical region where the seasons are much less distinct and the plant more or less grows and blooms whenever? Good culture sheets will assist you in answering these questions.

2) Then ask people who grow in your geographical location how they fertilize: when, what plants, how much, what method of delivery, etc.

3) Next, compare the conditions to yours - for example one Phrag grower I know says "fertilize heavily" but he does not let his Phrags sit in saucers of water, so all of the extra fert drains away and no leaf burn. If I were to fertilize heavily I would risk burning leaves because I use saucers and the salts will build up in the standing water.

4) Experiment - Try one method for a whole growth/bloom cycle or one full year. Trying one method for only a few months then switching will be of no use since it is not long enugh to see the method's effect on the whole cycle of the plant.

So, get the books out, call up yoru friends or go to your local orchid club meeting or ask questions at the next local show you attend, and start experimenting! I look forward to hearing your results a year from now!

Happy growing!

[sandra]

Thanks for the reply. More information again....a good thing.

The AOS recommends a high ph fertilizer this time of year to encourage flowering on Phals. I think I'm going to safely stick with a 20-20-20 year long but only on the Phals do a blooming fertilizer now through February (weakly, weekly).

Can anyone here explain what the adverse effects are of using high nitrogen or high phosphorous fertilizers, aside from root damage?

[Cynthia, Prescott, AZ]

In Dendrobiums, high Nitrogen in the fall/winter can cause a lot of keikis I am told. I'm with Kevin in that I have done very little fertilizing over the years, and have had to make a supreme effort to see that my plants are getting some fertilizer during the warmer months. Since there is this concern over Dens and fertilizer, I stopped fertilizing altogether earlier this month or late last month, and won't start again until the dormant Dens are starting to grow again. I plan to give some of the other plants, especially those growing or are heavy feeders, some fertilizer by hand. But since this is hard to do, and I am very pressed for time with so many things going on, it will probably not happen. When I can fertilize everything together, I add MSU for RO water to my RO water storage tank, along with a little Physan to keep down the algae in the left over water as it refills.

[Tobi]

What Cynthia said about high nitrogen fertilizing during the fall/winter months
for Dens. is right on and from experience I can attest to this as far as keiki
formation. My first 2 orchids were Phal type Dens. and being totally ignorant
to there care, I fertilized and watered weekly throughout the year using a
fertilizer high in nitrogen. Come spring I got nothing but keikis and no blooms.
Now I thought that producing offspring was pretty cool, but I wasn't getting
any spikes. My ignorance continued through the next year and the same thing
happened again. More keikis!! Finally after reading up on this and joining our
local orchid society, I cut back on my fertilizing to every 4-5 weeks (unless
they are actively growing or spiking) during this time. I now have blooms
twice a year and many keikis which are maturing.

[mayres]

Loved your post Kevin - Fred should make this a "sticky" on fertilizing. I have been using nothing but worm tea for the past 4-5 months - seems to be working! My plants look as good as ever and 35 or 110 mixed genera plants are either spiking or blooming! :-) I will probably use regular fertilizer again one of these days, but not for the time being. Yes - experimenting makes it interesting. Good luck to you Sandra as you explore what works for you. Obviously, in this case, there is more than one road that can be taken to get to the same or similar destinations.

[sandra]

Mike, I think I'm going to subscribe to the same theory as you, "less is more" and save myself some money while at it. Or additionally, maybe I'll do the blooming fertilizer now for the Phals just through winter and that's it. I'll just keep worming it up for now. I have a huge Dend. that won't quit spiking and flowering. It fell off a shelf during a storm not long ago and I lost over 50% of the flowers and one psbulb . It's now ready to blossom again where the spikes were lost. It's never been fertilized.

OR, maybe I'll do what Tobi does, every 4-5 weeks.

Originally Posted by Tobi

My ignorance continued through the next year and the same thing happened again. More keikis!! Finally after reading up on this and joining our local orchid society, I cut back on my fertilizing to every 4-5 weeks (unless they are actively growing or spiking) during this time. I now have blooms twice a year and many keikis which are maturing.

[OrchidArmyWife]

Help, i am lost when it comes to all the different fertilizers on the market for orchids. Does anyone have any good suggestions on what they have used and has given them good results? This is the only thing that is really driving me crazy what to use and what to not use, that is the question!!! LOL Help would be great. Thanks

OAW

[kmarch]

Check out the chapter on fertilizing in Ortho's All About Orchids or any other decent book on orchid culture. Fertilizing, how, what, when is subject to 1) what kind of orchid you have - there is no one approach that applies to all orchids, 2) the conditions underwhich the plants are being grown, and 3) the habits and preferences of the grower.
There are different approsches to fertilizing outlined in a different thread.

[Tobi]

Hi Lisa,
There are so many different types of fertilizers and people feel differently
about their views on when or if to fertilize and with what. I personally have
been using MSU (Michigan State University) fertillzer for about 3 years now
and I find it satisfies all my different varieties of orchids. The ingredients are:

19% Total Nitrogen
4% Phosphate
23% Potash
2% Calcium

The Micronutrients (which is less than 1%)
Iron
Manganese
Zinc
Copper
Boron
Molybdenum

[sandra]

I am dealing with the exact same issue right now OAW. It's all of a sudden, grabbed hold of me that I must fertilize (don't know where I picked it up either) and with the more I'm finding out and with all the additional supplements to go with fertilizing, I'm depleting my fun money account and rapidly. It can get very expensive. Very generally speaking, from those I've asked, it's been the majority who feel that a bloom booster (every other watering) now through the end of winter is recommended on Catts and Phals. Once Phals start spiking it's also recommended to stop all fertilizing. I've also been using seaweed which is supposed to add green growth and nourish the growth that's already there. I'm not necessarily recommending any of this to you as I'm still in the dark with all of this; I'm just telling you of what I've been recommended. (Everybody has a different opinion on the topic of fertilizing though, that's the problem!) Where my gut reaction is saying, TOO MUCH is to this additional chemical nutrient I just bought called, Floralicious Plus which is to be used, alternating with the bloom booster, one week on, one week off. I keep coming back to the theory, 'less is more' and am seriously thinking of quitting everything except the seaweed supplement and worm tea. There's just too much out there and too many opinions to choose comfortably.

[mayres]

Sandra's approach of "less is more" is a good rule to follow. I have been using nothing but worm tea for the past 5-6 months - my plants seem to be doing better than ever. Before that I just picked a fertilizer called "orchid fertilizer" by Gublers at Lowe's - seemed to work fine too. You can go with the recommended frequency on the container - or to make it really easy, dilute it down even further and then use every time - goes with the saying weakly weekly - that way you don't have to keep track of which weeks you used it last. When in doubt - use LESS.

[PhalPal]

My take on this is the fertilizer companies would like us to think we need a new fertilizer for each season and each different genera of orchid.

I have gone months without fertilizing and didn't see a difference. However, given the care-taking soul that I am I feel the need to feed everything. It just makes me feel good and gives me an excuse to play with my orchids. It makes them smile, too, or at least I like to think so.

I use mostly worm tea and seaweed extract. I find them great to mist with for a little foliar feeding; I use this on all kinds of plants. My cyms get Osmocote in addition to the above. Occasionally I will use a mix from Norman's Orchids, a huge phal producer. I alternate with their stuff just to use it up because long ago I felt compelled to get it. It has 20% Nit/16% Phos/15% Pot and a bunch of micronutrients similiar to MSU. Norman's uses this ALL year and does not use 'bloom busters' of any sort, never altering their schedule. I think they should know what they are talking about, so I believe them.

I haven't had one adverse problem using any of the above, which is important to mention. Nothing got burned, nobody died. Everybody seems to be happy. So, that's my concoction and I'm sticking to it.

[PhalPal]

I don't remember where I read it on this forum, but is it true that 'bloom busting' can cause fungus on phals???

BTW - thanks for the great post Kevin, very useful

[WIB]

Does worm tea count as fertilizing? -- Bill

[WIB]

The usual doctrine that I've read is "weakly, weekly," usually meaning half- or quarter-strength of any old fertilizer. I've read that people like me who use collected rain water should add some tapwater from time to time to make up for the relatively low levels of calcium in fertilizers. I have wound up most fertilizing less than weekly and can't tell whether it makes a difference. Fertilizing certainly hasn't killed any of my plants. The ones I have in PrimeAgra (I forget the generic term, HECA?) I assume will require fertilizer. -- Bill

[kmarch]

I should have added to my previous post that fertilizing is not necessary. I don't fertilize and my plants do ok.