Cattleya Root issues...

[Chris in Hamilton]

This is the problem I am having but don't know if Matt's is the same. The plant is Laelia fidelensis that I won in a raffle but it happens with others as well. The roots start to grow really well but then the root surface or tip dries out and sometimes develops dead dry areas. They always seem to heal and start growing again but it would nice to have it not happen at all. You should be able to see the two new tips at the edge of the pot. Those are coming from a root that dried. Also should see dry spots on older roots. There were no roots on the plant when I got it in December. It is about 1' below fluorescent light and gets a few hours of afternoon-evening sun. I will be setting up a rain barrel this week but use tap water with PH of about 6.8. Fertilizer is 25-10-10 made by one of the larger companies and intended for orchids. Half strength once a week. Humidity runs around 70%. I do know I was not watering enough until a month or so ago and think that was the problem but other opinions would be much appreciated.

Recommended fertilizer rate is 1/2 teaspoon per gallon.

[Carolla]

I'm looking forward to answers too... I had a similar problem with a Psycopsis. I ended up giving it to someone else, I couldn't get it to root into anything and its still struggling for my daughter. Very frustrating! Good luck!

[sciencegal]

It almost looks like the roots do not like the medium. When they get close or touch it they stop growing.

[Chris in Hamilton]

The brown nubs you can see are roots that were well established in the medium. They died back to the ends you can see. The ends you can't see are in the medium and good to go. I have plants in bark, wood, coconut shell and hardwood based mediums but that doesn't seem to make much difference. Some are growing through the drainage holes with no die back, others do this.

[sciencegal]

I heard some information a while ago that I have not decided if I believe or not. This orchid grower said that cattleyas especially will kill off their own roots when they are disturbed. The reasoning was something like if they are in the forest and their tree or branch falls off or over the orchid will not want to waste energy on the old roots or pb's. This is supposed to explain why you have to repot when new roots are showing because in the process of repotting they will kill off their own roots. Again, I don't know if this makes sense but many have observed the old roots die when they are repotted. Maybe picking up the pot and wiggling the plant makes them think their home has been or is being destroyed.

[Chris in Hamilton]

Sounds strange enough to be true. I almost always lose the older roots after I repot. Pretty much guaranteed when changing the medium.

[raybark]

Well, yes.

As roots grow, they "tailor" themselves to function optimally in the environment into which they are growing. Once they've grown, they cannot change. Move them into a different environment, and those roots are no longer optimal for it, so they wil fade, and new ones must replace them. The bigger the difference between old and new, that faster the old ones will fail.

The browning root tips are an indication of some sort of trauma, whether that be chemical, mechanical, or environmental. Usually is see that sort of thing when actively growing roots come in contact with a substrate that is very absorbent, but dry, and it literally sucks the life out of them.

[Chris in Hamilton]

Thanks Ray, I'm going to put it down to environmental (waiting too long to water) and not worry too much unless it happens again.

[raybark]

By the way, the 25-10-10 @ 1/2 tsp/gal comes out to about 165 ppm N. Using it half that concentration one time per week is quite reasonable, so unless your pH is WAY out of whack, I see no issue there.