I have trouble growing orchids in bark...

[eggshells]

They are under control but if anyone knows of a way to get rid of them for good, without killing the plants, I would very much like to know about it.

This takes a lot of work but best is to repot everything with fresh media. Rinse plant well through running water. Remove all dead leaves as they can be hiding in leaf axils. And spray with Safers Endall II with reckless abandon repeating every week.

Forgot to say follow the label

 

[NYEric]

Is anyone else wondering
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What the heck is a milk jug!?

 

[Shiva]

This takes a lot of work but best is to repot everything with fresh media. Rinse plant well through running water. Remove all dead leaves as they can be hiding in leaf axils. And spray with Safers Endall II with reckless abandon repeating every week.

Forgot to say follow the label

That's what I'm using now, but I was hoping for something like a neutron bomb for mealies.

 

[NYEric]

Mealies are tough, even after I think I got them all I find some later. I found patches of them when the temps started to drop here. Nothing like swabbing them with 91% isopropyl alcohol! Die plant suckers!!

 

[eggshells]

Endall is kill on contact so you may have to be really vigilant. When you see something spray right away. I tend to coat the whole plant with that concoction. Especially the hard to reach areas. I dont have any mealies as i tend to send back the highly infested one to the seller. Major concentration is the point where bark meets the axil usually.

 

[NYEric]

My combo of Merit 75, w/ neem, Dr. Browns soap, and alcohol seems to get them for a while but I only sprayed the plants; maybe I need to spray the bark also!

 

[Shiva]

They remind me of tribbles in Star Trek : born pregnant!

 

[Leo Schordje]

Woah, slow down.

Malachi, the sanderianum is due for a repot. But please don't try a potting mix you are not familiar with on that plant. Use a potting mix you know how and when it will go from wet to dry.

As I tell people in my talks. You can pretty much grow orchids in just about any mix you want IF you understand how and when to water. I grow in bark based mix, I know a local grower who grows the calcareous loving Paphs, like bellatulum and concolor in nothing but pure New Zealand Sphagnum, and she has keep plants growing and blooming this way for 20 years or more. It is just a matter of knowing how and when to water and fertilize.

First. Is the mix you are currently using for your other orchids working well for you? If yes, then just repot the sanderianum into that mix. Simple as that. Don't complicate matters trying a new mix on an expensive plant. Also as to the gratrixianum, even though it was just repotted, go ahead and repot it into your own potting mix, so it will be on the same schedule as the rest of your plant. USE THE MIX THAT YOU KNOW WORKS FOR YOU. (not shouting angry, just want to make sure you don't miss my point) I have killed more expensive plants by trying some new '"magic" mix that is supposed to be more "scientific" and the "ultimate" high tech solution to handling a plant with a touchy reputation. In the end, I do best with difficult plants when I use the potting mix I am most familiar with, in part because at a glance I know if it needs water, or if it is time to repot, or time to fertilize. Then the difficult plants grow well for me.

If you end up with a bunch of plants in a number of different mixes, you won't be able to individually customize a watering schedule. You will have to be able to check them individually every day. Pot ALL your orchids into the same basic mix. Or if you use more than one potting mix. Put all the plants in one mix right next to each other, and all the pots in the other mix right next to each other. Plants in the same size pot and same potting mix will generally need watering on the same day. Make life easy for yourself. Settle on a mix and stick with it. Adjust your watering schedule to the potting mix you like to use.

Or, if time for watering is in short supply, adjust your potting mix to your watering schedule. This second option is more difficult to work out the details, but once you do it works.

An ideal potting mix should be one you understand when to water.

 

[The Orchid Boy]

I may wait to repot the sanderianum until April or after it blooms. I'll probably wait to repot the gratrixianum until next year. I thought about a mix of medium orchid bark, coconut husk chips, a tiny bit of coir, perlite or small lava rock, and charcoal for the sanderianum.

For the thrips, have you tried submerging plants in water and trying to get them off?

Edit: Leo Schordje and I must have posted at the same time. I know, sometimes my mind races a million miles a minute, but that is how I learned most of what I know about orchids.

Leo: Do you think I could use sphagnum in the mix (about half or less sphagnum)? If I do use sphagnum, how often should I repot and should I worry about the acidity of the sphagnum and adding alkalinity? Thanks so much.

 

[Shiva]

Very good advice Leo. And it's always good to repeat it.

 

[Leo Schordje]

In terms of a reality check. I use 3 potting mixes for all 1300 orchids in my collection. Through years of trial and error I have adjusted them to all go from wet to dry within a day or so of each other. This way, the whole collection can be watered on the same day.

There is nothing magical about my mixes. The first is a medium grade fir bark, charcoal, sponge rock and coconut husk chunk mix, roughly equal parts bark and coconut, and the bark-coconut mixture is 4:1:1 :: bark-coco : charcoal : perlite. This mix is shaken over a window screen to eliminate fines. Then I dampen it and mix, so it is moist when I do my repotting. If I am potting Paphs, I'll top dress with a little sand or crushed oystershell depending on whether the Paph is a limestone lover or not. Sand for the acidiphiles.

The second mix is the fine version of the first, but I use a 1/2 screen to eliminate the big chunks and a window screen to get rid of the dust and powder. A 2 inch pot of fine mix will dry about the same speed as a 4 inch pot of the medium mix.

The third I use is straight Chilean Sphagnum moss. I try to pot loose enough that the moss goes wet to dry in the same time period the bark goes wet to dry.

That is it. I settled in on this pattern after 15 years of trying everything new under the sun often with tragic fatal results. I've been growing orchids for nearly 40 years, and the last 25 or so I have been really happy that with the growth my mix gives me.

This doesn't mean I never change. As the price of bark went up and quality of bark went down, I experimented on cheap throw away plants and settled on the addition of coconut husk chunks to my mix. It was a year long trial and error, but it worked and I am happy with it.

There is no reason to use my potting mixes, it is just a FYI about what I actually do. You can grow orchids in just about anything you want, if you know how to water the mix.

New material I am looking at as an 'extender' that will retain structure, allowing a bark mix to last longer, is shredded rubber mulch. It was on sale at 1/2 the price of bark. I am now testing it to see how it works as a component in a mix. But I am testing on plants that are expendable.

Hope this helps.

 

[Leo Schordje]

I may wait to repot the sanderianum until April or after it blooms. I'll probably wait to repot the gratrixianum until next year. I thought about a mix of medium orchid bark, coconut husk chips, a tiny bit of coir, perlite or small lava rock, and charcoal for the sanderianum.

For the thrips, have you tried submerging plants in water and trying to get them off?

Edit: Leo Schordje and I must have posted at the same time. I know, sometimes my mind races a million miles a minute, but that is how I learned most of what I know about orchids.

Leo: Do you think I could use sphagnum in the mix (about half or less sphagnum)? If I do use sphagnum, how often should I repot and should I worry about the acidity of the sphagnum and adding alkalinity? Thanks so much.

I think the mix you described as what you use for your other orchids is just fine. The only addition I would make is top dress the sanderianum with a little oyster shell (1 teaspoonful per 4 inch pot) or use horticultural lime if you don't have oyster shell handy. I get mine from a Saddle and Feed shop, where they carry feed for poultry. Its cheap.

I have seen my friend Cathy grow and bloom rothschildianum and sanderianum in nothing but New Zealand Sphagnum. It certainly can work, and work very well if you know when to water. And adjust your fertilizer to the mix.

Again, when tackling a species with a reputation for being touchy to grow, though sanderianum is really not that difficult. It is best to stick with a potting mix you already know how to use. Your original mix sounds fine.

Thrips. I tolerate a low level infestation until autumn. Every fall the whole collection gets sprayed. I will admit to using pesticides in a manner not consistent with their labeling. You should not do that. I spray with a cocktail of Mavrik, Enstar II, & Pentac. All in a single tank mixture. I do a repeat spraying 10 days later. Without fail, the entire collection is bug free and stays that way until the new recruits start coming in next spring-summer. Key is every living plant in the growing area or that potentially will be near the growing area gets sprayed. Don't want any hidden pests undoing the work of the spray. This cocktail seems to get them all, mealy bugs, scale, thrips, you name it. That's it. Most of these chemicals are not recommended for home use. There are others that will work, this is what works for me. I have too large a collection to play around with more home, or pet friendly products.

For what it is worth.

 

[The Orchid Boy]

This doesn't have much to do with the thread but what are some more 'acidiphiles'? I know Paph. delenatii is one.

 

[NYEric]

I will admit to using pesticides in a manner not consistent with their labeling. You should not do that. I spray with a cocktail of Mavrik, Enstar II, & Pentac. All in a single tank mixture.

"Better living through Chemistry" - Sign at Dupont Bohpal!!

 

[Rick]

As I tell people in my talks. You can pretty much grow orchids in just about any mix you want IF you understand how and when to water. I grow in bark based mix, I know a local grower who grows the calcareous loving Paphs, like bellatulum and concolor in nothing but pure New Zealand Sphagnum, and she has keep plants growing and blooming this way for 20 years or more. It is just a matter of knowing how and when to water and fertilize.

Yes. This is the point I infer with the thread on EC management of pots/potting mixes.

Definitions of "calcareous loving", and "acidophiles". Are pretty much worthless to me since looking at the potassium overdose issue. Even the traditional "acidophile" delenatii grows best at pH 5.5 to 6.5 like every other paph, and as noted by Leo, a species that grows on limestone can be grown in sphagnum moss quite succesfully (theoretically an acidic pH).

But a commonality for all is that retention of monovalent salts (potassium and sodium) in the mix is minimized through appropriate watering/feeding rates. And the balance of divalent salts (Ca/Mg) remains above the monovalents.

If all you water with (and make up non Cal-Mag type ferts) is RO water, you will saturate your potting mixes with K pretty quick. Adding limestone or oyster shell extends the rate since what soluble Ca can maintain a positive ratio to incoming K into the mix.

If you water with tap water (the harder the more Ca available) you can get away with a higher K input with well drainging/non retentive mixes with good size well growing plants.

Conductivity measurements can be a good surrogate/crutch to "learn" how to water and feed, since you will be able to litterally be able to measure the build up of salts in any given type of potting mix.

 

[Leo Schordje]

Thanks Rick, well said.

 

[Stone]

New material I am looking at as an 'extender' that will retain structure, allowing a bark mix to last longer, is shredded rubber mulch. It was on sale at 1/2 the price of bark. I am now testing it to see how it works as a component in a mix. But I am testing on plants that are expendable.

Leo, I've read that Shredded rubber should never be used as it contains toxic amounts of Zinc.