Liz -

Two good sites for info regarding orchids and fertilizer:

Ray Barkelow's site on semi-hydroponic growing has a nice information page:
w w w.f i r s t r a y s.com/free_info.htm
[take out the spaces, I don't know why GW is giving me a spam alert!]

and Antec Labs has a page of articles on growing and feeding slipper orchids:
http://ladyslipper.com/magazin.htm

Both tilt toward the technical side of things, and if your head starts spinning (mine did) you probably wouldn't go wrong following the advice of many of the most experienced and successful growers on this forum: "Fertilizer? Eh, whatever stuff I have lying around!"

Some plants are referred to as "heavy feeders" but that only applies to growing in optimal greenhouse conditions. "Weakly, weekly" is what I do, using a 20-20-20 at somewhere between 1/4 and 1/2 strength. I don't care about the urea/non-urea question. I have too many plants in different parts of their growth cycle to worry about it.

IMO fertilizer is a distant #4 behind light, water and temperature in determining how an orchid will grow. For some plants it is also behind humidity.

When Richardol refers to "weakly, weekly" he is referring to the general advice to feed orchids once a week using a very weak dose. I found that phals grow year round, therefore I feed them weakly year round. Cattleyas slow down in winter because of less light, therefore I use a much lower dose of fertilizer, but I do continue to feed. Some dendrobiums (nobile, for instance) do not want any fertilizer at all while the den phals want a weak does year round. You must research each particular type of orchid you have to learn what they need.

Bark should not be treated any differently than other mediums. The exception might be NZ sphagnum moss, which holds fertilizer longer, therefore does not need fertilizer as often.

There is some light reading contained in the link where the three forms of N in fertilizer are discussed.

Here is a link that might be useful: Previous long fertilizer discussion

tee530 remarked: "[take out the spaces, I don't know why GW is giving me a spam alert!]"

This is an automatic response to any direct reference to Mr. Ray or his enterprise.

--Stitz--

Great information. I guess the bottom line is that I need to research my plants to better understand their individual needs. I'm most confused about the dendrobiums, so I'm going to get myself a good book on them.

Liz - what type of dendrob?

Jane

Liz, the general advice on fertilizer is to use one with high nitrogen during the main growing season when leafy growth is desired, and then switch to a low nitrogen fertilizer a few months before bloom is desired. Some exceptions, like dendrobiums, don't like a lot of nitrogen at any time.

I am new to the orchids. about 8 months. mostly phals. 1 cat. I fertilized for the first time, then read forum on fertilizing. 3-7 days after fertilizing my blooming phal is loosing its flowers. my cat is also showing signs of flowers dying. guess i should have read forum first
ken

As an aside, one thing to keep in mind is that fertilizer is not 'food' in the true sense of the word. Plants make their own food through photosynthesis. More appropriately, fertilizers can be looked upon as vitamin/mineral supplements rather than as a burger and fries. Just like humans, plants need certain elements to grow properly. An example is that people can die from lack of Vitamin C (scurvy), or that children will have deformed soft bones without calcium and Vitamin D, etc. We fertilize plants, be them orchids or rose bushes, to supply these extra nutrients which may not be available otherwise -- but sometimes are anyhow.

Try to keep this in mind so you don't go nuts if you are going on vacation and your orchids won't be fertilized for two weeks. It's not food, it's just vitamins; they are not going to keel over and die.

got a vanda for valentines day. have phals and cats. this vanda is growing without media, just roots. i can't water it every day. can i put it in some kind of pot with moss or bark? it seems to be wilting already. i probably don't have enough light for it either. maybe 3-4 hours sunlight daily. is that enough. my phals do fine in my gameroom with that amout of light. Thanks for the help
animal