Laelia (Cattleya?) purpurata watering
 

Hi,

I have a question about watering needs of Laelias (Cattleya?).

I've recently found myself with a few Laelias (purpurata, and some related hybrids). All seem healthy, new roots, and actively growing... It's potted in a Cypress wood chip mix, indoors, under grow lights.

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.

I've read that Laelia purpata loves to be watered during growth, but I'm a bit apprehensive of growing Catts soaking in a pool of water... Is it normal for these to require so much watering? Does anyone grow these constantly wet...?

I think having this species soaking wet all the time is a recipe for root rot. Do you have any pics? The plants might be dehydrated and need some extra moisture for a little while. Conversely, all the roots could have rotted out and that's the reason for the shriveled bulbs that won't fatten back up.

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).

I have a few (species and hybrids) and I grow them among my other cattleya hybrids with no special treatment. They grow well, probably the most vigorous of all my catts.

I grow in a shadehouse, in bark, in mesh pots, watering from overhead sprinklers 2 out of every three days in summer and weekly in winter.

I haven’t tried it, but I definitely would not grow them constantly wet - if by that you mean sitting in a saucer of water. If I get a plant that looks a bit dehydrated, I usually just mix in a few strands of sphagnum and wind a few across the top. That ups the moisture level for a while, then when I see they have recovered I remove the sphagnum where possible.

I don’t know exactly what cypress mix is, but if it is largely hardwood chips then it would hold very little moisture and would not be the medium I would choose for these plants.

Cheers
Arron

I agree with Arron. Definitely avoid putting in a saucer of water, which definitely blocks air-movement.

Jeff, I don't recall exactly where in the San Diego area you live, but now that nights are starting to warm up a bit, consider moving those C (L) purpuratas outside. That's where mine grow, and they do quite well. I have found them to be quite cold-tolerant (since yours have been inside, you do need to wait until nights are around 55 deg. F... next year they will be acclimated and then no worries, they're fine just a bit above freezing). Mine do better in baskets, wood even better than plastic, large bark so excellent drainage. If it gets hot and dry, just water more.

First of all, Laelia (Catt) Tenebrosa and purpurata share the same habitat.

Usually I water my tenebrosa at night in a more humid environment (HR = 60%). If you can give it these conditions (with night temp > low 60's) it will benefit from it. Cattleyas "drink" and "bread" mostly at night.
Putting it in a saucer with water might not be a good solution as it will also prevent air flow between the top and bottom medium layers (and obviously in between).

Sorry for the misspelling... Laelia purpurata.

I purchased these from Carter and Holmes, and it's potted in a "Cypress/Hardwood Blend and Spongerok". I've gotten a few Catts from them and they're doing fine indoors in the same medium.

I have a couple of other Cattleyas (species and hybrids) in BetterGro bark mix. I let them dry between waterings and definitely do not let them sit in water. They are doing fine indoors, under grow lights/windowsills. I've had them for a few years, got them to bloom most years, so I assume they are doing okay.

I'm struggling with the Laelia purpurata and Laelia pulcherrima. Roots of L. pulcherrima are declining this week - noticed root tips are becoming black today. Since new roots are emerging now, I've decided to repot them in plastic azalea pots (lots of holes, and have a few lying around) in bark medium.

It's getting mild in Mission Valley, but still some nights that dip into the 40s.

Thanks,

Purpurata does just fine in the 40's.

Jeff, I think that we're about done with cold nights. Even if it dips down occasionally, it's only for a few hours. For the purpuratas, I think that the benefits of growing in fresh air far outweigh the risks from an occasional few hours of chill, especially as the days grow longer and the sun brighter. Also, it's good to get them out before the sun gets more intense, so that they can acclimate.

Thanks for the advice, I've put them out and they seem to be hanging on. Many of the new roots turned black at the tips once I put them out. I'm not sure if that was shock from the new environment or due to some other cultural factors. Hopefully it will rebound.

I agree that orchids do much better outside. Overwintering orchids (and citrus) indoors has always been frustrating for me.

How many of the new roots Jeff? What proportion of the total amount of new roots?

Definitely hard or impossible to say right now what had happened - just due to uncertainty about the growing environment (temperature, lighting level, etc.) and the state of roots within the media.

A friend of mine suffered a freeze in a greenhouse shared with 2 other growers. Temps dropped into high twenties.
Most of the L. anceps died.
Most of the L. purpurata lived.

That the L. purpuratas lived at those temperatures doesn't surprise me. That the L. anceps didn't survive does surprise me... I wonder what other factors were at play, such as whether some were wet and some were dry (and if the L. anceps were in pots or in open baskets where they could dry quickly.) My L. anceps haven't gone much below 32 deg. F, but those of people who live in inland areas of southern California do experience temperatures into the high 20's F at least once per winter, sometimes more, and I have not heard of anybody having a problem with them.

There were 4 roots on L. purpurata, the 3 that just emerged all turned black. The 1 older root that was already into the media survived.

Same with the L. pulcherrima. It had 3 new roots, the 2 newer ones turned black. The one older root that was growing into the media survived.

New growths on both are steadily growing...

It's sitting next to a L. Finckeniana (doing fine, very hardy too...) alongside other Rl., Blc., Epc., and the temps have been in the 50s at night, one or two nights in the 40s.

My other Catts (luddemaniana, some labiatas, dowiana, a couple of hybrids) are still inside and doing well. I haven't had any issues with them.

Though... I'm about to kill my first Cattleya... Cattleya warscewiczii seedling... doing well for 6 months until I brought it inside. went downhill pretty quickly...

If consistently the roots that are growing into the media survive, while the other ones didn't survive (turned black) ------ then that would be something to look into -- such as the degree of growth of the surviving root into the media, and how well connected to the media those particular roots are ----- things like that.

Also considering humidity and rate of change of temperatures between two significantly different temperature levels.

And even considering that different kinds of orchids, and even different individuals (depending on conditioning etc) will have their own response to significant change in conditions that they're not adapted or accustomed to.

watering time?
 

"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."
Hi Southpark,
When you water each cattleya daily, for how many minutes (seconds?) do you water each plant?

Hi Fran! Thanks for asking.

As I grow the orchids in plastic pots with the drainage grates, I have to limit the amount of water being sprayed into the media - so as not to have the dishes build up too much water. Some water will emerge out the bottom of the pots eventually as the water makes its way down through the media.

I don't necessarily wait for water to come out from the bottom of the pot though.

Based on the size of the pot and the amount of scoria it contains ----- you'll develop a general understanding or feel about how much water penetrates into the depths of the media. This also depends on how much water is coming out of the spray nozzle. I set the adjustable nozzle coverage (spray width) to somewhere in-between a very directional setting and a medium setting. Somewhere in-between ----- ie. not too direct and not too sparse.

With this setting, I can easily just focus the water where I like - such as spraying the water more onto the media toward the sides of the pots. Here, I've seen no problems with dumping as much water as I like.

When the media towards the sides are sufficiently wet, there is expected to be enough moisture in the air within the pot for other roots (towards the centre of the pot) to absorb. It's ok to spray some water toward the centre of the pot too ----- but I put limit on it.

We know that catts generally can certainly handle root dry-out for some amount of time. And occasionally allowing for dry-out in the pot can (or will) cut down on (or even eliminate) chances of nasties or issues from occurring within the pot (eg. bacterial/fungal/pest activity). That is, may keep certain things under control (or at bay).

Fran --- the amount of water to be applied (which depends on duration of application and rate or water flow) certainly depends on pot size, and amount of media in the pot. For small pots with juvenile orchids, it may be just a few seconds around a pot. For large pots with lots of media - it may take much longer. The longer an orchid grows in a pot, the more roots are going to be in the pot (in general).

Also - having some idea about where the roots are occupying for a particular pot can be helpful too (eg. occupying entire pot, or occupying middle regions mostly, or upper part of a deep pot etc).

A good way to understand how much to apply is to have a particular size pot (eg. a relatively large one) with say 10 to 15 mm size scoria pieces. And then use the watering device (eg. water wand, or even regular watering container) to water the media. And after watering is done, carefully dig into the media to get an idea of the amount of water penetration into the media. Here, it will be possible to see roughly where the water has reached. From that information, you'll eventually develop a nice feel for how much water to be applied - to avoid any long-term wet dripping roots condition.

Each grower (including you) will have your method of watering and controlling the conditions within the pot. Every grower eventually comes up with their own way of keeping things under control.

Thanks. Yes, it's something I'll keep an eye out for. I've noticed how different plants of the same species can grow slightly differently. Interesting and a little frustrating.

My main question through all of this was if L. purpurata required a significantly different culture than so-called "standard" Cattleya conditions. At the time, the roots were still healthy and the media wasn't wet. I thought I may had been under-watering as some culture notes mentioned it required heavy watering. Afterwards, I likely went too far to the opposite end.

If standard cattleya conditions are fine, then repotting to a coarse media and lowering water frequency should hopefully help (and a breath of fresh, outdoor air!). The change in environment may have shocked it a bit, but it should be better in the long run.

Hopefully, I can share the plant in bloom in the near future...

I think standard Cattleya conditions. Mine live with the Catts, everybody gets the same treatment.

Definitely Jeff. The purpurata will certainly handle coarse media. Also - I found that watering the media in a wide pot away from the most concentrated regions of roots (eg. away from the central regions of the pot) is quite workable and effective. This doesn't mean that we can't water the middle regions. We can - but just place some limit on it.

Purpuratas as tough as nails. If they are shriveling that means that they are vastly underwater. Water is a function of the media more than of the orchid. All my plants get water every day for a long time.(automatically.) They do not rot because they are on a media that do not rot. Orchids will adjust their root to the media they are in and that goes from air to water, so the range is huge. You just have to be consistent and water according to the media.

It could well be Ovarz! Although, overwatering - or overly wet for relatively long periods could lead to root rot too. And then root rot can result in shriveling too.

Update:

While it was suffering under my care, indoors... It's beginning to take off outside. Multiple growths on the L. purpurata, L. Pulcherrima.

It's a bit embarrassing to show these... but I'm glad these are doing better.

Agree. Consistency is the key.

Not at all Jeff ------ as the sharing of information about how to grow the various orchids well - including these ones - is a great thing for the orchids and for the growers.

Seeing 3 new growths like that is a great thing.

...and two years later

They are all doing well, soaking up the full desert sun. And now... I see the first spikes developing on C. Pulcherrima!

https://live.staticflickr.com/65535/...2703a3e0_c.jpg

https://live.staticflickr.com/65535/...b4f64b67_c.jpg

https://live.staticflickr.com/65535/...d1bb4018_c.jpg

In my conditions I need to keep these, their near relatives and hybrids quite wet. Temperatures in the summer grow room are around 85 degrees F / 30C most of the time, and relative humidity around 60%-70%. Plants in semi-hydro shrivel if I don't water every day, even when water remains in the reservoir. Seedlings I receive in sphagnum must be stood in dishes of water or they dry out too fast.

Others here have much higher humidity than I do. I think your plants look excessively thirsty and are getting more sun than I would give.

Thanks, I agree with you on both points but this is what I've settled on for these brazillian laelias. I'm under a drought so I've reduced the watering to half or to a third of what I normally do. I've been putting saucers under all my orchids to combat that but I've run out of them at the moment. As for the sun, I was moving all my orchids (couple of hundred) every few weeks to avoid full sun... but I'm tired of it.