I have just repotted all my orchids in perlite with a tiny bit of New Zealand moss. I have noticed a few of the orchids are displaying some very light colored yellow leaves. Am I watering to much?

I always water when the pots are light to lift up, some don't need watering at the same times as other do. My Phals are in 6" pots and they don't need as much watering as the smaller pots do.

I chose this medium as a fellow member of our club just raves about using it. I like the fact it is clean, does not break down except for the moss. Does not harbour the bugs like bark does and is alot less expensive to use. She uses the same perite over and over, she boils it in a pot when she does her repotting and reuses it.

So far I have noticed the leaves of my orchids being alot plumper but I am worried about my one phap and my militonia having two tiny bottom leaves turning yellow.

Does anyone use this type of mix?

:wink:

Hmmm. I dont use straight perlite. Perlite dries too quickly for me and since It can get pretty hot here I have to water more often. I usually mix it with some other organic media. Also I fear that since I use quite fine grained perlite that it would compact too much and since its heavier, the paph roots wouldnt be able to push it aside as it grows.

The main problems I see here...fertilizer and pH. What fertilizer are you using? For a sterile medium like perlite and sphagnum, you will need a complete fertilizer with micronutrients, like MSU or Dyna-Gro. Next...sphagnum will acidify your medium, and most paphs (except for delanatii and maybe a few others) dislike an acidic medium. Your symptoms sound like chlorosis...which may be due to Nitrogen deficiency, or an acidic pH that prevents full N utilization. We need more info from you...and there are plenty of people who can help. take care, Eric

Having older leaves turn yellow is not too strange, and might just mean there is some new growth coming on. If the whole plant is going pale you might add a little epsom salts ( a tsp or two per gal).

If the repotting was very recent (within the last few weeks) I don't think it would be unreasonable to see a bit of shock to the plants as they adjust to a new media. But after a few weeks I would worry about adjusting what I was doing if they didn't turn around. Maybe reduce light for a while.

People get good results potting with virtually everything under the sun. Most of my non paphs are mounted or in baskets of sphagnum moss.

Oh boy I am not having a good week at all. If it is not fish problems then my orchids are not happy too. I have noticed now that a few phals are showing this yellow tinge to the leaves also.

Now should I go and repott them all with a bark, perlite, moss mix?

My fertalizers I usually use are high in the middle number. 10-52-10 or 15-32-15 I did read about paphs not doing so well with moss as it is acidic.

I sure would hate to move these orchids into new mix now but I also want the best for them too. Dyna Grow I have not been able to find it here at all. We have Miracle Grow, if you think I should leave well enough alone as they are can you please recommend a good numbered fertalizer that I should be using?

Epson salts is great stuff, I use this on my roses with great results. I can give them a shot of this if you think this will help. But the numer of fertalizer is what I really need I think to help me here.

My paphs are both pushing out new growths, so I guess this is a good sign. I will gladly put them into a mix though if you think i should do so. I have a new species coming soon "Niveum" I will not tamper with it when it comes as it will be a seedling.

So if you could please tell me what micronutrients I should be looking for that would be greatly appreciated.

Also, just out of curiosity what does bark have in it that is good for orchids versus the mix I am using?

:D

Good question. I dont know why bark is used for potting mix, but the practice I guess started with attempt to replicate what paphs grow in the wild, such as leaf litter. (Now why nobody uses leaf litter as potting mix I dont know)

Anyway, the best result I have is mixing different materials such what others here seem to recommend. I use a mixture of rice husks (my substiture for bark), charcoal bits and perlite. If I can find shredded tree fern I also add that in. My goal is to make the mix as long lasting as possible so I dont have to repot often.

The fertilizer I use is a local brand called siam which I believe is a 10-15-10 mix I use with my other orchids like vandas but at a reduced amount. This contains micro-nutrients such as calcium, zinc etc. This fert is weird in that it actually raises PH when I mix it with straight RO instead of lowering it so I dont even have to add in tap water to balance it out.

:idea: BTW, are you the one watering his orchids with used aquarium water? Also are your phals the only orchids exhibiting the yellowing?

Because I would think used aquarium water would contains ammonia as a by-product of fish waste. Could it be some orchids (in particular the phals) are ammonia sensitive?

Ammonia is toxic to fish at only a few ppm, and the filtration systems developed for aquariums are designed to convert the ammonia produced by the fish into nitrate.

Nitrate can accumulate if there is no algae growth and water changes are infrequent, but generally it will be much less than 50 ppm.

I use my aquarium water for my orchids, but I have not seen any yellowing. My hatchery has so much water, I can't afford not to use it. I've been using it for that last 3 to 4 years, that's when I started with orchids.

Good question. I dont know why bark is used for potting mix, but the practice I guess started with attempt to replicate what paphs grow in the wild, such as leaf litter. (Now why nobody uses leaf litter as potting mix I dont know)


I use it.

Yes, I have also used leaf litter before but too much of a hassle to go out and collect old leaves from the ground. I guess I'm just lazy. :roll:

Why can't you add crusted dolomite lime into the perlite and sphagnum mix to reduce acidity as the moss breaks down? What size is the perlite? Large #4 perlite would be OK. Presently I am experimenting with growing a Paph stonei seedling in a mixture of large #4 perlite and sphagnum moss with a sprinkle of crushed dolomite lime. Many years ago I planted a wild collected Paph supardii in the same type of mix and it grew bigger and bigger every year. I did not repot the plant for three years. I finally took the plant out of the pot to examine the roots....they were all healthy. The roots stuck to the perlite and glued to the inside walls of the pot.

Paphman

Hi, to answer a few of the questions.

I don't use aquarium water for any of my house plants.

The phals, paphs and militonia are the ones showing a tinge of yellow. Now I have been told that I water to much....... :D yep I can agree to that also I have been using a fertalizer all the time with a high middle number. Next watering I am going to use a balanced fertalizer with the micronutrients that I bought today 20-20-20

The perlite is the large stuff and the amount of moss i have is like two pieces in the middle and a couple on the top to hide the perlite a bit. So mainly it is perlite.

Why do we plant in bark. I asked my uncle whom is an orchardist and has a huge horticulture background. He says he does not undertand why we use this stuff. His answer was that bark breaks down very fast as well all know. It also robs the nitrogen from the plant as the break down process begins. "house plants" like orchids contrary to what we would like to believe don't like being repotted every year. We repott way to much and also repot into unecessary bigger pots, yep I can attest to that too. I have done this on several occasions and waited and waited for that bloom. Perlite he says is a sterile medium, it will not break down and can be used over and over by boiling it for a few min and then reusing it. It is clean does not harbor bugs etc.

I wanted to get away from the repotting thing to every year due to break down and this is why I chose this stuff. When he came over to see my plants he said that I do water way to much and I am getting nothing but great leave growth. Also my fertalizers are lacking those key balanced ingredients and I am low in Nitrogen and Iron as someone stated in a previous reply here.

So I will leave them in what they are in and when I water again I am going to use the balanced stuff for a while and see what happens.

Thanks all for the replies...... :D

"house plants" like orchids contrary to what we would like to believe don't like being repotted every year. We repott way to much and also repot into unecessary bigger pots, yep I can attest to that too.

Well, that may be true for other genera, but my slippers seem to respond well to repotting on more of a regular basis, at least so far, I plan to continue the once a year route. I also like to be able to inspect all of the roots until I know my growing conditions are down pat. I do have one plant that I am experimenting on....haven't repotted yet and got it last July, and I am quite sure it had been a while since it had been repotted last.

I would just caution you also that it sounds as though you are changing a lot of variables (media, fertilizer, and watering) at once so, it may be hard to nail down what a problem or success is related to. JMHO, of course!

I would also add some lava rock for weight. I think you will be OK with the plants in perlite just as long as your keep the watering routine consistent.

Paphman

I forgot to mention that I condition my a water with oak leaves before I use it in my tanks. some of my fish need very acidic water and I use plenty of ock leaves in their tanks. My waste water is usually pretty close to neutral. I have several drums filled with waste water where I combine all of the various types of water for my fish (hard, soft, acidic, neutral, etc)

Do you have any Tanganyikan Cichlids. They were my specialty in my younger days. They like real crusty high pH water.

Do you have any Tanganyikan Cichlids. They were my specialty in my younger days. They like real crusty high pH water.

No, I have in the past, I specialize in killifish and apistos, even though I am not breeding as much as I did when I didn't have kids and when they were younger. I don't have the time to care for fish, but orchids are much easier to take care of, timw wise that is. In fact at the end of this month on Memorial Day weekend I am going to the American Killifish Convention, this year it is in DC. There are quite a few orchids keepers in the killi club.

Yes I've seen allot of posts that refer to killies and poison dart frogs.

Yes I've seen allot of posts that refer to killies and poison dart frogs.

I post on so many other boards on various subject matters that I forget what I have posted on which site :ohmy: