OrchidSafari ARCHIVES*

Sure. Fertilizer is always one element in a balanced growing program. Increase fertilizer, increase light. If you increase one but not the other, poor growth will result.

I think too much nitrogen and too much shade will produce very lush and fragile growths on Catts. The pseudobulbs will snap off at the lightest touch!

My problem is that most of the time my fertilizer stays in the bucket because my syphonex doesn't work most of the time. I take it apart clean it out blow it out and, it still doesn't work.

Increased light alone won't harden growth. Hard growth requires a good balance of food, light and temperature. It is sort of the reward for figuring the whole equation correctly.

So does anyone know what the difference is in the formulation of the Miracle Grow for orchids that was advertised in the AOS Bulletin this month and the garden variety Miracle Grow.

It is a VERY high NITROGEN fertilizer, you can not find the formula on the can, but they put it in the bulletin, I was given a can and will not use it for that reason. Last year I tried an experiment to reconfirm my theory of only low nitrogen. I used chicken manure tea very high Nitro and the catasetums, grew huge and the bulbophyllums too BUT NO BLOOMS on plants that usually bloom twice or three times a summer! No More High NITRO for ME!

** No exact percentages on the Miracle Grow product at this time.

I am against using high nitrogen fertilizer in the home. NO good if you ever want to see nice blooms!

I have a proportioner that uses 100:1 ratio. I have yet to figure out how many tablespoons per gallon makes that ratio. Do I simply make a strong solution and let the proportioner draw it out at the correct rate?

If you want to feed 1/2 teaspoon per gallon, add 1 cup plus 2 teaspoons of fertilizer to each gallon of concentrate and dispense at 100:1

What about foliar feeding?

It seems to me you need access to the plant in order to foliar feed and orchids have precious few stomata. I do feel one should flood seed pods with fertilizer solution as it seems to make them form better, so maybe foliar feed is a benefit.

I agree all plants need a good balance, Everything in LIFE is a question of balance and finding the solution is the key!

I do not "foliar feed", I think it caused the root rot in Paph. However on all my bonsais, I do that about once every couple of months.

Foliar feeding has no meaning for me. When we water or feed, we flood the whole plant. I figure an orchid plant enjoys a shower just like everybody else. Yes, Phals, too.

Whenever anyone asks me how I fertilize my orchids, I always say I "foliar feed" them. Of course, that's virtually impossible on the face of it, but what I mean is that I spray the leaves and the entire plant. I do not soak the potting media. I use 20-20-20 more or less once a week for 3 times a month and once a month I use 5-50-17. All the same way at the same concentration. 1 TBS/gal. However -- I grow under VERY bright conditions, I water the vandas copiously on a daily and sometimes twice daily basis. I water all the rest about once or twice a week. Also, remember that I grow outdoors in a shade house with no sides! Excellent natural air circulation.

My sentiments, exactly. Orchids have a waxy cuticle that covers the leaves. It makes the exchange of liquids very difficult. It is their way of saving water. Just like cacti. Does all ionic exchange occur in the velamen?

I hope no one will be offended, but our handout piece by Rex Johnson is entertaining but meaningless. Years ago, Stockdale, Ayres and others sampled tropical rainwater and found the N content to be 12-16 PPM with pH range of 5.6 - 6.2 for a rather wide area of the tropical rain forest. That isn't optimum, it is just what is. All this pencil whipping is futile.

When I remember to fertilize (not often enough) I have to use a watering can where it will reach and hand dunk the rest. There must be an easier way. I tried one of those "thrive" mixers but found the water flow just too strong.

I also have very high light so I fertilize a tablespoon in a gallon every watering, water first and then come back round with the fertilizer. Recently have switched to Champion urea free 20-20-20 and 12-30-25. Good stuff and pink!

Forgot to add that I am a great believer in using Superthrive and include that in every fertilizing. I am talking about during the growing season for all of this -- in the cool weather, I barely fertilize and minimize my watering. Also, I should add that almost everything is growing in baskets, rather than pots, but I am now beginning to shift most of the Catts into pots.

Ed, Can you translate 12-16 ppm on N into percentage of available N?

Here's the magic equation for PPM: Take the fertilizer per cent and multiply it by 75. Normally we want to control on N, so take the N per cent, say 20! 75 = 15. That's the guide number for a 20% fertilizer and with it you can do any calculation you want. It means the PPM for 1 ounce of that fertilizer in 100 gals of water. If you want 120 PPM, divide 120 by 15 and you'll see you need to add 8 ounces of that 20% fertilizer to 100 gallons of water to get it. Once mastered, this is all you'll ever need to know to compute PPM like a pro. I collect nice fees for knowing this, so don't tell anyone.

I wouldn't want to pop any balloons, but fertilizer is measured in per cent of N, P and K. Orchid plants are constructed of C, H and O. Makes a lot of the concern we evidence seem pretty futile when the plants actually manufacture their own substance. We help if we can, stay out of the way if we're able.

Do you use a waterbreaker on your hose? That does help even when fertilizing.

I'm sorry, I have never heard of a waterbreaker. What is it?

A waterbreaker is a devise you screw on the end of a hose to break the stream of water into many smaller streams and it seems to add air to the stream of water so that it doesn't disturb the mix as readily.

I read in one of the AOS bulletins that Vandas only open their stomata's in the A.M. so watering should be done then - transpiration will bring the water from the roots into the plant. Any thoughts??

Gosh. I didn't know that! I have always watered as early in the day as possible because with our dripping high humidity, they really need a long time to dry off and I always heard that Vandas should never be even damp when the sun goes down. Of course, my area is notorious for late afternoon thunder storms!! When that happens I check the plants carefully before watering.

Reference April 96 issue of Orchids, Article by Dr. David Grove.

Thanks. I've been reading his new book. It is excellent -- the best I've seen for Vandas. I have always heard that what 5-50-17 (Root 'n Bloom) really does is stimulate root growth -- the blooms come as a result of that. I always figure that I am fertilizing now for the flower spikes that will be showing up in about 6-8 months. There are no "quick fixes" that you can apply today for blooms next week or next month.

I use super thrive too, with each watering, now I have a big bucket with fertilizer. super thrive, I dip the vandas into this bucket daily, it seems to help a lot. I saw that Maricle grow fertilizer in our Home Depot, if you have HD in your area, look for it.

In the home the plants seem to need more! I was not getting blooms and GOOD NEW GROWTHS bigger than before un till I increased fertilizer and stopped high NITROGEN food.

Sorry, had to put the birds to bed and move to the computer room. I'm back now. As far as my fertilizing, I used to not fertilize at all, but now I have a siphon hose that dilutes the fertilizer as I water. I use Dyna Grow with the siphon and powder mix of some sort when I hand spray. Now I fertilize every time I water. Never with a high Nitrogen I'm trying osmocoat on a few...We'll see how that works

Does the axiom hold true for orchids that N is for vegetative growth, P for blooms, and K for roots?

Not precisely. High N will inhibit bloom and will promote soft, heavy vegetative growth, but too much of P and K will over stimulate a plant, as well. Most bloom boosters don't work for orchids because orchids make up the bloom growth many months before they actually flower. Good, consistent general cultivation is a much better bet.

Question, I use all RO water all the time, are you of the opinion to add "iron and mineral" into it?

I wouldn't add anything without an analysis to see what was needed. Best bet with RO is to cut back with some tap water - the among depends on how bad the source water is. Gets some life back in the water. Also use a good trace element mix. We use Peters Peat-Lite Special, 20-10-20, which has a great trace mix and no urea. There are many good fertilizers, of course. Dyna-Grow formulations work well with RO if you don't mind paying the exorbitant price for the product.

I water with RO. I had it analyzed at a lab, and add my N,P,K and trace elements to get it back to 'orchid drinkable'. Watering with out chemicals in the RO is like distilled water. Only has H2O and not much else. Only good for getting the plant wet.

I DO NOT use DYNA GROW any more as the plants were blooming on immature growths, did not get that with Peters or with Champion. Growths are MUCH bigger BUT I still will only use a bloom booster or an even based 202020

Does the high N inhibition of blooming go for all orchids? I had heard about Dens and Paphs....but not Catts.

I don't think one can speak about 'all orchids' in any area, but for a very wide diversity of plants, high N encourages vegetative growth and inhibits bloom. Orchids were plants a long time before they learned they were exotic.

Has anyone used Aqua Flow, have any comments???

I'll jump off the bridge again, but then I'm going to get some bungee cord. Look at your study material, toward the end, where the scripture is quoted about 30-10-10 for bark. This is the longest lasting fantasy in orchids. Sure, extra N will break down bark, but you won't get it out of 30-10-10 because it has less than 20-20-20. Peters formulations are the standard, and 20-20-20 general purpose fertilizer shows 9.5 per cent nitrate and ammoniacal N, the only ones useful to orchids. Look at the formulation on 30-10-10 and you will find 5.3 per cent nitrate and ammoniacal N. The urea in both formulations will simply wash out of a pot of bark since there is no soil organism group to convert it to plant-useable forms.

What is RO water?

Reverse Osmosis. It is a Thin Film Membrane that allows H20 to get through but not the larger molecules. Hence it softens the water without adding the sodium in the ionic exchange methods.

Ed, that goes with the question about does all of the work occur in the velamen? Are the microbes in the velamen? I understand the dirt, root process, but still can't get it into this thick skull how a vanda hanging bare root gets the food!

RE the velamen question. Velamen is a multi-layer (usually 7 in orchids) absorptive tissue that takes up water and nutrient so the central root fiber can transport it to the plant. Nitrate and ammoniacal N are accepted, for practical purposes, as food and pass through the velamen path to the plant. Urea is not ready for use by the plant and must be broken down by soil enzymes, bacteria, etc. into usable forms. The velamen is a permeable membrane. If the concentration is greater in the plant than outside, fluid will cross the membrane into the plant. If the reverse is true, as when water evaporates and fertilizer and ambient water salts remain, fluid can be induced from the plant into the surrounding concentrate.

Ed, digressing a bit, but does it hurt plants to be wet overnight if they are growing in a shade house. Good air movement from a natural breeze.

It rains in the tropics about 4 every afternoon. All plants are wet all night and all have fine air movement as in all the leaves move with the breeze. I don't like to have free water on the plants at night, but I don't mind if they are damp.

Ed, have you seen Vandas in 'the wild'? I always assumed they grew on trees in dank steaming, steeping, stinking jungles, where there was enough nutrients to be garnered from the dust and dirt in the air and from falling leaves etc. Seeing Dr Jays last post now makes me wonder.

The vandas I've seen 'Naturalized' have their roots wrapped around the tree limbs and trunk just like Catts. So I would assume, they get fed the same way,...From the canopy above.

I just repotted most of my plants into bark this time around, roots just didn't stand up well to sphagnum and I was thinking of changing to a higher N at Q other watering alternating with a more balance fertilizer but Ed's posting has me thinking otherwise.

I try to water early in the day to ensure the foliage is dry, but days like today that start off fine and then the rain comes means some of them will remain damp with some water droplets still around. It's just 8.5 C at the moment so not much chance of them drying off any more.

Experiment, remember Ed's formula is GREAT for a greenhouse, but not always correct for the home!

The point being that each has a different set of growing factors. Change one aspect of the equation and you must change others to get the balance. Different periods of light, water, temp, air movement, etc....makes for a bit of experimentation.

I'd certainly agree. If it came down to one general statement, I'd say most people over feed by a substantial amount. Little food and lots of water adjusted to a proper pH will grow really good plants.

I use bark too, and didn't worry about fertilizer. at all. Now that I rt of the plant, including the root tips.

Is it important to check the pH? Do you check your pH? Critical and yes. We use a pen type pH meter - about 50 bucks. Ours is made by Hannah Instruments, I think. pH is important because it affects the availability of nutrients and trace elements. At elevated pH levels, iron and magnesium are bound up in insoluble compounds and phosphorous becomes unavailable. A plant can starve while being fed a high pH nutrient solution. We also like to keep dissolved salts soluble because they wash out of the pot easily and do not accumulate to burn plant tissue.

Why don't you make some tests with your pool kit, then take them to the hospital and check them out. Go the other way and check pH readings for several samples titrated to precise pH points. Once you know what your pool kit will do, you can decide whether it is adequate for greenhouse use. I'd say 0.5 was about all the tolerance one could allow. pH units are very large and progress geometrically to huge values.

Go to the hospital lab and ask them for some bromcresol purple. Mix it with some triple distilled water and have them titrate the mahogany brown reaction to a pH like 5.6 or 5.8. Above that, the reaction will be purple; below, the reaction will be yellow. Extremely accurate, it is a one drop test, so a small bottle will last forever. Bob Ring and I wrote it up in a Bulletin 30 or so years ago. I'll find the article if you have a problem.

I check mine just before it goes to the orchids....I have also collected some from the pots as it drains and checked to see if the pot is changing it. This could be an indicator of something wrong in the pot...i.e., too many salts, too much decaying matter, etc.

The Florida Orchidist
Vol 33 No 2
July 1990

There are many types of fertilizers available. The manner of application and the quantity to be used varies with each one.

The most widely used fertilizers are the water soluble types, most commonly showing a ratio of 10-10-10, 20-20-20, or 30-10-10 on the label. Some fertilizers also list a number of trace elements or "micro nutrients" on the label.

First let's identify the numbers:

A 10-10-10 ratio fertilizer contains equal parts of nutrients
10 parts Nitrogen - used by the plant, primarily for leaf growth.
10 parts Phosphorus - used by the plant, primarily for good root development.
10 parts Potassium - necessary for blooming
70 parts inert ingredients
Equaling 100% (or 100 parts)

A 20-20-20 contains double the amount of each nutrient equally, the balanced formula.

A 30-10-10 fertilizer contains more nitrogen and less of other components.
30 parts Nitrogen
10 parts Phosphorus
10 parts Potassium
50 parts inert ingredients

Now we understand what the numbers on the label mean. The 10-10-10 simply means that the required nutrients are present in equal proportions. The 20-20-20 is the same balanced mix with the exception that the components are more concentrated. The 30-10-10 ratio indicated that this fertilizer contains 3 times the amount of nitrogen in proportion to the other 2 nutrients.

Basically we use the balanced fertilizers on our orchids. The plant uses what it requires; the excess is washed away at the next watering.

The usually recommended quantity of 10-10-10 fertilizer is one pound per 100 gallons, which comes to approximately 1 teaspoon per gallon. If you use the 20-20-20 fertilizer, which is more concentrated, use only one half teaspoon per gallon of water.

Most people use too much fertilizer. This can be detrimental. It is wasteful...the plant uses what it needs, the rest will be lost, or the pot builds up salts in the bottom.

Secondly, this build up of fertilizer salts can, in time, burn the growing tips of the roots and may cause loss of vigor and roots.

Thirdly, over-fertilizing can cause soft growths which may not harden properly. This soft growth can retard good flowering.

We use a balanced fertilizer on most of our orchids at the rate of one teaspoon per gallon of 10-10-10 or one-half as much if we use the 20-20-20 ratio fertilizer.

Why use the 30-10-10 type of fertilizer?

To pot our orchids we use osmunda, tree fern fiber, perlite, moss, charcoal, stones, woodchips and many other suitable materials. Most widely used, however, is tree bark, straight or mixed with other materials. When using bark, we need to use the 30-10-10 fertilizer.

Organic materials, when being decayed by micro organisms, release nutrients, including nitrogen which plants utilize for their growth. Decaying bark, however, releases very little nitrogen. The myriad of fungi and molds growing in it consume almost completely. This leaves practically no nitrogen for the plant. To compensate for this imbalance, we must apply an additional amount of nitrogen with the fertilizer. Therefore, for any plant potted in bark, the 30-10-10 fertilizer is required. The amount required it one teaspoon per gallon.

Most decaying matter will provide other elements necessary for good plant growth. These "trace" elements are not being provided to plants being grown in inert materials such as stones, charcoal or empty wood baskets, especially when rainwater is being used for watering. To prevent problems, use a fertilizer that contains trace elements or micro nutrients. If they are in the fertilizer, it will be indicated on the label.

How often should you fertilize? In summer or when you see your plant in active growth (prior to blooming) fertilize every 2nd or 3rd watering. In the winter, or when you see no new leaf or new root growth, fertilize infrequently or not at all.

Don Howe's experience has indicated much of the black spotting on foliage can be prevented by hardening the plant off with a change of fertilizer; i.e., application of 10/30/20 when new soft growths are almost mature. The soft growths are very susceptible to diseases, and this lower-nitrogen fertilizer change hardens the growth (which was soft from too much nitrogen), thus preventing the black spots. (Don Howe, 'Orchid Problems', USL Short Course, 12/01/90)

I believe in constant feed and my potting mixtures are a minimum of 50% charcoal, so I use Dyna-Grow 7-7-7 at 1/2 tsp per gallon til I use up 5 gallons of solution in the Dosatron (generally one to two weeks, depending on season/weather), then switch to a 5-gallon bucket of 2-15-4 at 1/4 tsp/gal. My phals and paphs are about 1/4 small bark, but I repot at least once a year and do not find enough bark decay to worry about utilizing a higher nitrogen fertilizer. I have a mixed collection and find that alternating between the two fertilizers in this way seems to be keeping everything happy.

The best message here, is to cut package directions by at least 50%, use high potassium fertilizers to harden off growths, and forget high nitrogen unless you have marked deterioration of bark mixes. The need for 30-10-10 with bark media is being questioned more often of late.