FERTILIZATION!!!!

[RosieC]

Originally Posted by Ray

3) If you want to make life real simple, water with a very dilute fertilizer (maybe 50-75 ppm N) at 3 out of every 4 waterings. If you prefer to use a schedule for your feeding, increase the concentration proportionately.

Ray, something I've never been sure about. I've assumed in the past this advice of 3 out of 4 is based on weekly watering. What I'm not sure on is whether I should adjust concentration based on daily watering.

My mounts get daily watering and I use plain (rain) water every 4th time. Should I use a different concentration to I use in the less frequently watered pots. Currently I always have some of the pots being watered each day so I just pour the same mix over the mounts as well, but often wondered if that's a mistake.

I feel I should be able to work out the principle of the thing but have just confused myself in this case.

[Call_Me_Bob]

as said before, any balancedd fertilizer would be just fine. i like to use MSU fertilizers. and also, some (all?) orchids cant consume nitrogen if its supplied by urea. so you might want to make sure that whatever fertilizer you get, the main nitrogen source isnt urea

[Ray]

Originally Posted by RosieC

Ray, something I've never been sure about. I've assumed in the past this advice of 3 out of 4 is based on weekly watering. What I'm not sure on is whether I should adjust concentration based on daily watering.

My mounts get daily watering and I use plain (rain) water every 4th time. Should I use a different concentration to I use in the less frequently watered pots. Currently I always have some of the pots being watered each day so I just pour the same mix over the mounts as well, but often wondered if that's a mistake.

I feel I should be able to work out the principle of the thing but have just confused myself in this case.

That's a tough one, Rosie.

One might logically consider that (for example) if you water twice as often, you should cut the fertilizer concentration in half, and that seems reasonable for potted plants, but a mount does not retain moisture and fertilizer like potting medium, which allows the plant to take up more over time in between waterings.

One might argue that, as the mounted plant only sees food and water for the time it is actually being irrigated - seconds, rather than days - it might actually be better to increase the concentration. That, however, puts the plant at risk of "poisoning", if taken too far.

I use the same solution for all plants, no matter how they are grown.

By the way, I take "3 out of 4" to apply to any watering schedule, not just weekly.

[RosieC]

Thanks Ray, those are the same considerations I was mulling over and couldn't decide between. That and the fact that pouring water over them washes away and small residual remains of the fertilizer salt... although I do remember a conversation here on OB a while back where someone thought moss on mounts actually collected a lot of fertilizer salts.

Basically lots of factors at play...

But I'll do the same as you and just use the same for everything. Thanks Ray

[Ray]

Media may accumulate salts, but unless they are in solution, they are not available to the plant.

Then, if they are accumulated in the vicinity of the roots, and you douse them down with water, they instantly become "available" at concentrations that can be toxic.

[RosieC]

Thanks Ray, great to have your insight on this. Basically that means is I douse down I need to use a lot of water to effectively flush, like I do with the pots. That's what I've been trying to do anyway, and with all the rain the UK has been getting I have masses of rain water to do it (and some mounts are outside getting a lot of rain, actually someone told me at a show last month that I need to fertilize more due to all the rain at the moment).

[Paul Mc]

Very good info Ray! I've been wondering about how often to fertilize mounts myself. Guess I'll be upping the amount I do now, given your information.

[Bill U.]

I have 2 phals that are all currently being fertilized with a 30-10-10 fertilizer (miracle gro).

I have been doing reading on this forum and realized that I may be giving them too much nitrogen because they are all potted in sphag. Other places on the forum have posted that Grow More 20-20-20 (yellow) and Orchid Plus 20-14-13 are other fertilizers that would work.

Should I change from my current fertilizer to one of the others? Is one better than the other?

Sincerely,
newer phal grower that is seriously confused on what kinda of fertilizer to use...

[Ray]

Bill - how much of the 30-10-10 do you mix, and how often do you feed?

[RosieC]

It's generally thought that a balanced fertiliser is best (all the numbers the same), however if you get the mixed concentration right then yours should be fine. The higher the N number the weaker it should be mixed and visa versa.

Personally I would use what you have to use it up, but if you can get hold of a more balanced one then get that next time.

Generally speaking because you need to use less if the N number is high it's also cheaper to buy one with high numbers. I use a 20-20-20 with tap water and I mix it a lot weaker than the old 2-0.6-2 that I used to use and is much cheaper as a result.

To calculate how much to use of any given fertiliser use Ray's calculator here.Fertilizer Mixing Calculators

You enter the N value, the number of times you water/flush each month and it gives you a recommended mixing rate. This ensures you are not overdoing the nitrogen.