To fertilize or not to fertilize... That is my Question

[Cym Ladye]

Originally Posted by Rachelle-lapensee

..... I dunk them for about 10-30 seconds in distilled water to allow the bark and roots to soak up the water and then remove them from the water.

What is this with the distilled water? Unless you have the "water from Hell" in your tap, this is not necessary and can actually deprive the plants of a proper ph. Millions of orchids around the world are grown in water other than distilled. They seem to thrive although the water distillers might wish otherwise!

BTW, a 5-10 minute soak is better. Change water with each plant, however, unless you want to spread disease, bugs and virus. Have you visited the AOS website and looked at their culture sheets on Phals? It might help you answer some common questions.

Growing orchids is not rocket science, just common sense in the long run! Learn what the species get in nature and duplicate it the best you can in your environment.


CL

[RosieC]

I also use tap water for most of my orchids, including all the phals, Dens, Paphs & Onc Alliance ones.

I use rain water on my more sensitive Masda and Restrepia and if I have a lot of rain water I also use it on the others, but most of the time the Phals and the like just get tap water.

[Ray]

Also, if using distilled water (or any pure water source), the use of regular, "store-bought" fertilizers will give you a solution having a VERY acidic pH, probably lower than the plants would like.

You'll either have to test it and adjust accordingly, or purchase a fertilizer intended fo pure water.

[RosieC]

Hi Ray,

I remember hearing that before, but the thing I'm not sure about is whether that applies to rainwater as well.

Is the reason because there are less disolved salts to buffer the pH, if so I would expect it to apply to rainwater as well, but I'm not sure.

I've only recently started using rainwater and I usually use it with no fertiliser or very weak fertiliser on the Masda and Restrepia, but I sometimes use it for the others as well, and I'm concerned I should be using a different fertiliser.

[Rachelle-lapensee]

hello everyone. I feel hopeless...

I went out and purchased my fertilizer yesterday, but by reading the back I seem to become more confused...
I have never used fertilizer before (except for premixed).

So I'm going to type the instructions here and hope that you guys can shed some light on what I should be doing. ( hopefully I'm not getting annoying...)


Directions:
Mixing rates for Phalaenopsis – Mix 6 ml of fertilizer per 5L (1 tesp/gallon) of water

Application time:
Fertilize every 2 weeks from April to August during this period of rapid growth. The bark should be moist before fertilizing. Never fertilize a dry plant. Use Plant prod 15-30-15 flowering plant fertilizer from September to March.

Thank-you so much everyone for all your help and support.

[RosieC]

OK, the advice to use a different one for flowering is ignored by a lot of us and we just use the growing one all year. Many people say there is no benefit in changing to the flowering version. So just ignore that.

The advice to have the bark moist before fertilising is also ignored if you fertilise weekly. The old idea was that you don't fertilise a dry plant because it could burn the roots BUT that was when the fertiliser was used much more strongly on a monthly basis. If you follow the weekly weakly idea then you SHOULD have a dry plant to encourage it to suck up the fertiliser.

As a quick rough guide I would personally go for half the strength is says, 3ml per gallon of water, and then fertilise every week. Make sure once a month you flush through with no fertiliser to remove any build up of salts.

Finally, what are the numbers on the one you have bought. The flowering one you have said above is 15-30-15. What are the equivalent numbers on the one you have? With those numbers someone could do a more precise calculation of the stength we would recomend weekly (rather than my rough and ready 'half the strenght weekly').

[Rachelle-lapensee]

Originally Posted by RosieC

what are the numbers on the one you have bought. The flowering one you have said above is 15-30-15. What are the equivalent numbers on the one you have? With those numbers someone could do a more precise calculation of the stength we would recomend weekly (rather than my rough and ready 'half the strenght weekly').

The one I bought Is 25-10-10.

[Ray]

Rachelle, I recommend using fertilizer at a concentration of 100-150 ppm N at 3 out of 4 waterings, with that 4th being plain water to flush residues from the medium.

To determine the amount of fertilizer to use, divide 13 by the %N on the label, and the result is ml/L to get 125 ppm N, so you can round up or down for convenience. In the case of the 25-10-10, that would be about 1/2 ml per liter. Frankly, I'd use the 15-30-15 year round, at about 1 ml/L.

[RosieC]

Interesting how the bottle is way over your calculation Ray. Maybe that is why they say don't fertilise dry roots, because their recomended concentration is so strong.

Rachelle, I would always trust Ray's calculations on this and at Ray's recomended concentration you can water dry roots. I know he recomended that somewhere in another recent post.

[Rachelle-lapensee]

Originally Posted by Ray

Rachelle, I recommend using fertilizer at a concentration of 100-150 ppm N at 3 out of 4 waterings, with that 4th being plain water to flush residues from the medium.

To determine the amount of fertilizer to use, divide 13 by the %N on the label, and the result is ml/L to get 125 ppm N, so you can round up or down for convenience. In the case of the 25-10-10, that would be about 1/2 ml per liter. Frankly, I'd use the 15-30-15 year round, at about 1 ml/L.

Ok... I think I understand... (Think)

Now if I understand correctly 1/2 teaspoon (level) to 1 gallon is the correct ratio????