When to change to bloom fertilizer for orchids

[solgirl]

When do you change over to bloom fert, just as spike starts growing or when buds start to appear?

[raybark]

Fertilizers do not have "instantaneous" effects on plants, so both scenarios you mentioned would be too late. However... "Bloom" fertilizers don't really do a thing for blooming.

"Way back when" Dr. O. Wesley Davidson of Rutgers University devised the first commercial "mineral" fertilizer, Miracle-Gro. He later devised a high-nitrogen version - Mir-Acid - for plants that like the acidity, including stuff like azaleas and orchids. Both are really good, general purpose fertilizers. Unfortunatley, over time, folks began noticing that their plants fed Mir-Acid grew beautifully, but were getting "stingy" about blooming.

It turns out that excessive nitrogen is akin to feeding kids sugar - gives them lots of instant energy, but does nothing for overall nutrition, and can lead to a "crash". So, to counteract that, the manufacturers added lots of inexpensive phosphorus-bearing minerals to the formula, and the marketing folks pushed the fact that this new formula "boosts" blooming. It didn't "boost" anything, but in fact, what it really did was dilute the nitrogen, allowing the plants to bloom normally.

The bottom line is that orchids don't require a great deal of fertilizer in the first place, and while there may be some that quash blooming if they are overused, there are none out there that promote bloming at all. For the best blooms, provide the overall culture the plants needs, and it will bloom to its genetic peak.

[solgirl]

Thanks so much for the info. I use a pinch or less of 30 10 10 to a gallon of water now. The plants are growing nicely and rooty.

[raybark]

I am not a fan of the "pinch" measurement; it's just too vague. I recommend using a target concentration, and sticking to it, so that you can have a basis for future adjustments.

I feed every time I water - 2-3x/week in summer - and I use 50 ppm N. If you divide 4 by the label %N, the result is teaspoons/gallon for 50 ppm N. For the 30-10-10, that would be 4/30, or about 1/8th tsp.

If you feed once a week, I'd up that to 100 ppm N, which uses 8/%N = roughly a quarter teaspoon per gallon.

[jai_star]

Let me give my 2 cents here I use to fertilize a lot following the rule weekly weakly well guess where that got me I have a cymbidium that didn't spike this winter instead more pbulbs were formed and still forming I overdosed it too much on fert! Also I have a cattleya that is so healthy that every new bulb does not have a bloom on it. So my new regime only fertilize twice a year once I spring and I summer other than that give lots of light and water I rest my case

[solgirl]

The measuring scoop from Jacks Classic 30 10 10 that I use says that I am using a little shy of 1/4 tsp. It looks like a pinch I guess. My plants are in bark so I figured they need a little help. I have been using it since cutting the spike in the spring.