Urea as N source in Fertilizer?

[discgo]

Hello All - I've got a quick question about urea as the nitrogen source in fertilizer.

Does it really take a year for urea to break down and become usable by the plant? This is what I've read on the 'net and seen several warnings against urea as the N source.

I've been using Jack's Classic Orchid Special 30-10-10, and 29.82% of the N is from Urea. Have my plants been getting no nitrogen all summer?

I'm new to orchids so this is my first full year of keeping them and the grow has been decent but since I don't really know what to compare it to I thought I'd ask.

How should I feed blooming plants? I just got 2 cattleyas that are in bud, should I use a balanced fert or low N?

If I new new fertilizer, any recomendations? Dyna-Grow?

Thanks for any input.

Cheers!
discgo

[Aniko]

I don't know about the braking time of urea, but concerning the orchids need for fertilizer I learned some basic things:
You have to avoid the accumulation of salt (fertilizer) in the pot, on roots and potting medium by soaking in water and flushing well, regularly.
Orchids are relatively slow growing plants, as result they need less food then non-orchids and can survive for long time without fertilizer.
You can use any balanced fertilizer like (20-20 20) or something close to this, in a light dilution: about 1/2 or 1/4 of the usual.
Fertilizers labeled as "orchid food" have the same components, just the instructions demand a lower concentration. I use Shultz Orchid Food (19-31-17), it works well for me.
As I remember, a high % of N stimulates foliage growth.
Aniko.

[atcrosby]

I use Dyna-Gro and it's fairly easy to use each week when I water my plants. The only thing is to remember to flush them out periodically so that the salts are leached out of the pot.

There are so many orchid specific plant foods you shouldn't have to mess with anything else. Also, get some SuperThrive and add a drop to your water to help the roots and the plant. It's awesome stuff.

[discgo]

OK, so here are some quotes I found online regarding urea -

"Do not use fertilizer containing urea on any orchid. Urea requires breakdown by soil microbes. A toxic salt build up can occur that can burn tender roots."
from orchidlady.com
and

"all the other urea based fertilizer requires greater than a 72º temperature and bacteria in the soil to become readily available to the plants."
from hilltoporchids.com/
I have my orchids in med bark which I don't think is sterile and the day temp is usually above 72 so I should be fine, right?

I may switch a plant or 2 to Dyna Grow and see if I see any difference.

Thanks for any comments.

Cheers!

[Aniko]

The bark is sterile

[discgo]

I don't think the bark is sterile, How can it be after being used as a potting medium for several months-years?

I've used fish emulsion in the past when I had plants outside and I know after that the bark would not be sterile.

Maybe I'm confusing something here.....

[Aniko]

Of course I meant new bark.

I would switch to a balanced fertilizer instead of experimenting with that one (with urea).
Aniko.

[jerrymeola]

Peter's is one of the favorite fertilizers for commercial orchid growers in Florida (probably because it is readily available in 50# bags and priced for commercial use.

I use it and have had excellent orchid growth after all this is my business. I have never seen a problem from the urea base.

I do not recommend 30-10-10 fertilizers. The high nitrogen encourages leaf growth at the expense of flowers. Mediums (commercial mixes use much more peat moss than hobbyists) break down using the nitrogen to decompose. 30-10-10 is for these conditions or very old bark. If you re-pot every couple of years or grow in mediums other than bark and peat, I recommend a balanced 20-20-20 mix at a teaspoon per gallon.

I do not like high phosphorus fertilizer like 8-35-12, usually sold as 'bloom boost'. They do not seem to do anything special. A healthy plant blooms well. That said there is an exception to everything.

Nobile Dendrobiums should not get any nitrogen fertilizer after September or it prevents flowering. Yet Yamamoto Dendrobiums told me to fertilize the blooming size plants I am getting this week three more times with high phosphorus fertilizer as they are not fully developed canes yet. It is unrealistic for a hobbyist to have the experience to make this call.

My previously bloomed Nobiles are getting no fertilizer anymore.

Hence this is the basis for my recommendation of a balanced fertilizer once a week (more outdoors in rainy season less when not growing actively) at a teaspoon per gallon.