Quote:
Originally Posted by Jeff214
Since the p-bulbs began to shrivel, I tried increasing the watering from once a week to three times a week. When that did not help, I tried placing them in a saucer of water. This seems to have helped... although the P-bulbs have likely shriveled to a point of no return... All the new growths are happily making new leads and roots.
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For orchids that have regular roots (eg. not roots that have made some adaptation to being fully submerged under water or in semi-hydroponic and/or hydroponic conditions) - constantly LIGHTLY moist roots with ADEQUATE air-movement among the media and roots is no problem.
Very wet dripping roots where the water around the roots doesn't move adequately within some amount of time - can be a problem.
What gets or kills the roots is if the water around the roots don't move enough - allowing oxygen level in the water in and around the roots to get too low. This can occur if air-movement through the media and pot and around the roots is inadequate.
So - to prevent too much resistance against air-movement through the pot, growers can try large enough pieces of media, or can try shallow enough pots, or whatever method works. There are certain kinds of plastic orchid pots where the bottom is basically plastic mesh - incredible drainage, which is often very nice. Generally - whatever pot or media style we use, there's often some compromises - eg. more airy big pieces media - faster drying, or shallow pot - maybe requiring frequent watering.
Now, even if we have appropriate size media, and good air movement, and good drainage pots - there are also other methods growers can use to cut down on issues with roots - such as watering method, watering schedule.
An important recommendation is to develop a reasonably accurate picture about the state of the roots and the media ----- at any particular time.
If your bulbs are all shrivelling - then first check the roots. The bulk of the roots may be grey in colour, and very wet, and soggy, and dead. This can happen if the roots and media are dripping wet all the time, due to a combination of the media type, media size, and not enough or big enough holes in the bottom of the pot, and even not enough air-movement in the medium and pot and around the roots.
For cattleya - I grow in very good drainage pots and scoria media, with good air-movement in the growing area. I water every day - using a weed-spray nozzle.
I water the orchids (even in their big pots) the same way. I water the media only - and .... for extra safety .... I can concentrate (focus) the water on the media CLOSE TO the SIDES (rim) of the pot. That's where I dump most of the water - along the outer regions toward the sides of the pot.
Much less water goes into the middle parts (central regions) of the pot.
In this way, the bulk of the roots around the middle regions of the pot still get adequate moisture (due to a slightly moist medium at the centre), or the roots toward the middle can still gather moisture from the air anyway when the medium toward the sides of the pot is wet.
It's not necessary to water every day. It just depends on the growing environment, and how fast the media dries. And cattleya can definitely handle having their roots (and media) being dry for a little while - which can also cut down on certain kinds of activity like bacterial/fungal/algae activity.
Also - if the cattleya orchids are growing outside in outdoor or semi-outdoor environments --- in some parts of the world, may have to keep an eye on the media and watch for things like snails or bush snails etc ..... in case they sneak in at some stage.
One more thing is ----- if you were watering only once a week, then it's also possible that your cattleya might not have been getting enough water. But - in any case - if you ever notice shrivelling bulbs --- ie. all of them shrivelling - then check the roots - just in case.
Finally - I've included some attached photos as examples of my watering of some of my catts. Even though I have very good drainage and air-movement, a
nice rule-of-thumb is to
avoid having roots and media dripping wet for long periods of time. I have no problem with directing most of the water into the
outer portions of the scoria
near the pot rim. Another approach is to water as usual - but just watch out for the mentioned condition (ie.
roots very wet for long periods of time with inadequate aerated water movement around the roots and media - leading to oxygen starvation of roots).