Smaller leaves? - Orchid Board

grasshopper · #1 08-11-2010, 03:32 PM

I moved a NOID phal to S/H in January 2010 and it immediate began putting out a new leaf. Within 4 weeks a new bloom spike emerged. When this happened, the new leaf that had begun growing in stopped growing when it reached 3". The older leaves (there are 4) are about 6" long. I initially thought the shorter leaf was due to a shift in energy from leaf growth to spike/bud/flower growth. The phal bloomed in late April and the last flower fell in late July. I cut the spike to the base and within a week another new leaf began to grow in. This leaf also appears to have reached the 3" mark and has slowed, while yet another new leaf is growing in. What is causing the leaf span to all of a sudden shorten so drastically?

If it helps, the bloom spike was about 8" tall and the flowers were about 1 3/4" in diameter (10 in total). Oh, and I'm fertilizing weakly, weekly with Schultz orchid food (which I don't really like, but is what I have at my office...I use MSU or Dyna-Gro at home).

Has anyone else had a plant change leaf size when converting to S/H?

Ray · #2 08-11-2010, 04:31 PM

Only if you don't feed it enough...

What is the formula of the fertilizer you're using, and how much are you mixing, and how often?

grasshopper · #3 08-11-2010, 05:12 PM

Formula is 19-31-17 and the instructions state to add 1/4 tsp per gallon every watering. I water this orchid 2x a week using this measurement, with a "water only" flush every 4th watering.

grasshopper · #4 08-11-2010, 05:34 PM

So, Ray...based on the information I found on your website (which is fabulous, by the way), it appears that the 1/4 tsp per gallon measurement does not provide enough N. I used the calculator on your site and it seems that if I'm aiming for 125 PPM for nitrogen, then I need to be watering with 1/2 tsp per gallon with every watering. Is that correct?

Ray · #5 08-11-2010, 10:50 PM

Yeah, but I'll be honest, I have a hard time understanding why the difference between 125 and 20 ppm would have THAT drastic of a difference.

I think there must be something else influencing the growth rate. Can you tell us more of your culture?

In 15 years of experimenting with S/H culture, I have never seen what you are seeing.

RosieC · #6 08-12-2010, 09:42 AM

How have the roots done. Have a lot died after moving it, and have many grown to replace them.

If your Phal has gone from having lots of roots to not many, then I would expect this sort of difference in leaves. I find bigger leaves come with better root system.

If the plant has adapted well to S/H and put out a lot of new roots then I would not expect this, however if a lot of the old roots were not suitable for S/H and died off, but not many have grown to replace them I would expect the leaves to be smaller.

grasshopper · #7 08-12-2010, 11:04 AM

I had not thought of that, Rosie. I haven't checked the root system in a while, but at last check (back in March before it bloomed) there were 3 new roots growing in. They stalled out when the flowers began to open before they really got down into the LECA. I have been misting them daily to keep them from drying out. Now that flowering has finished, these roots have begun to grow again and I'm trying to coax them downwards. I haven't pulled the orchid out of it's pot since March to see what the rest of the root system looks like, so I don't know if there are more new roots below the LECA...I'll do that later today.

Oh, and I'm growing this orchid in a windowsill at my office. Humidity is low - around 30% - but there's not much I can do about that since I sit in an open workstation area. I mist daily to help and I've got a few small ferns sitting next to the phal to help, too. The window is an east window, so the plants get full sun from about 7:45am to 10:30am, and so far they seem to love it.

grasshopper · #8 08-13-2010, 04:38 PM

Took a look-see yesterday afternoon and lo and behold new root growth is minimal. The 3 new roots I mentioned above are still the primary roots, and they have still not grown down into the LECA (though they are beginning to dive). I did notice that there are a few green-tipped nubs shooting off from older roots that didn't fully rot but have that brownish hue of a "not so happy" root. So, it seems that with a little patience and a slightly stronger fertilizer solution, the root system will continue to grow (fingers crossed!) to support the larger leaves.

Thanks for your help, everyone!

Ray · #9 08-14-2010, 10:39 AM

If you are growing in an air-conditioned home, the evaporative cooling from the medium can chill the root zone and quash root growth.

If you can grow the plant really warm, or put it on a heat pad to warm the root zone, it will respond very well.

Duane McDowell · #10 08-14-2010, 12:18 PM

The shorter leaves are indicative of a problem (new leaves should be as wide as or wider than and as long as or longer than those that preceded them).
Sounds like you found your culprit - loss of roots.
And, it sounds like you're on the right track to recovery - removing bloom spikes. It was a little unclear to me - have you got the growing roots in the medium? If so, that should be good. If not, get them into the medium where they can do the plant the most good.
I don't know about s/h, so I can't comment on specifics related to it, but the above would be good general practices.
I think that experimentation is a really good thing. Kill some plants - it's the best way to learn how to grow them well!
Good luck.