Possible reasons for short Phal spikes?

[Lacie]

I have been growing orchids about 5 years now, and have 6 Phals (two species, the rest hybrids, mostly NoIDs). A few of my larger Phals the last few times they have bloomed have put out very short spikes. They still spike regularly and bloom fine, but I was wondering if people had thoughts about what causes the short spikes? My guess is it is either from under-fertilizing (I don't fertilize often, maybe once every few months), or low humidity (I'm a windowsill grower; I have humidity trays and sometimes mist, but that's it. My plants all seems to do fine anyway so I've never worried too much about humidity).

Obviously not a major problem, but curious if people know why this happens. I just think longer spikes look more impressive

I've attached pictures of one that has had this issue. The first photo is of it currently in bud (spike is roughly 8"), the second is from the last time it bloomed. I have another plant that did the same think, the last time it bloomed the spike was maybe 6" and only produced a few flowers, but I couldn't find a picture.

[dbarron]

Frankly I consider it an improvement for in house display As to causes, no idea.

[aliceinwl]

I've noticed that my Phals in higher light areas produce shorter spikes with more flowers. I also have been really trying to consistently fertilize bi-weekly over the last growing season and this seems to have improved the number of flowers, how often the plants send up spikes, and branching on the spikes.

[Lacie]

Thanks for the responses!
Aliceinwl - my Phals are not in very high light (N facing window with shade from buildings) so it might be the fertilizer as you suggest. I am trying to be better about fertilizing regularly, so maybe we'll see what happens next blooming season. Oddly, one Phal I never fertilize (mostly because it is potted in packed sphagnum so I water it very infrequently) is putting out two spikes right now. We'll see whether they stay short I guess!
And yes, dbarron, I guess it does help them stay compact!

[Ray]

Fertilizer is not a particularly important part of orchid culture, but they need a small amount on a regular basis.

Manhattan has some of the purest water in the country, so you're not even giving it the calcium it must have, which most folks get from their water supplies. Whatever fertilizer you use, it MUST have both calcium and magnesium in it, with that water supply.

Personally, I recommend K-Lite, but the MSU RO formula is also acceptable, and with either one, 1/4 teaspoon per gallon at three out of four waterings ought to be fine.

[Lacie]

Thanks, Ray! I had no idea I needed to supplement Ca with my water for Phals. I had previously been using the Grow More urea free formula (no calcium), but recently got Jack's bloom booster (though haven't used it yet), which has some calcium though not as much as the K-lite you recommend. I think I will order the K-lite, since I know my Paphs also want calcium - I was providing some through eggshells, but I imagine the fertilizer will be more effective. Thanks again for the tip!

[Ray]

Most plant nutrients can be transferred from one part of the plant to another, as needed. Calcium, however, is pretty tightly bound once it is absorbed by the plant, so it is important to make sure the plant has a steady supply.