Paph. moquettianum sp Isn't Growing

[Judi]

I have a Paph. moquettianum sp. that my son gave me back in spring of 2007. It came in a tiny pot. I repotted it in the fall of 2008 in a 2 ½ inch pot in a paph blend and packaging popcorn at the bottom of the pot in case the pot was too big (it was the smallest I had). It grew very slowly when I first got it, but doesn’t seem to have changed over the last 10 months or so. I have it on a shelf behind some short onc. in indirect light. Humidity is about 50% now, and higher in the summer when it is outside. I water once a week in the summer, but more often now that the heat is on—there is no hot air blowing on it. It never dries out completely, but it is not wet either. I mist several times a day in winter. Night temps don’t go below 65. Can anyone tell me what I am doing wrong and why it won’t grow? I also have a paph supersuk that is doing very well.

[slipperfreak]

Well it doesn't sound like you are doing anything wrong but it also doesn't look like the plant is in fantastic shape. It is definitely time to repot it. I would do that, and if the plant has rotten roots you'll know that it suffered from overwatering. Have you been fertilizing it?

[OrchidSue]

To me the plant looks overpotted. In general, Paphs. like smaller pots. I would suspect the roots are rotted. You should check the roots and see their condition.

Susan

[Judi]

Joe, I still have some 20-20-20 fertalizer left that I use weakly weekly; I use rain water. I will repot--I'm afraid it didn't grow much roots because I haven't ever seen any through my clear pots. Guess I don't have much to lose! Susan, I'll try to get a smaller pot. Thanks for the replies!

[slipperfreak]

A 2.5" pot is fine for that plant and you probably won't be able to get one smaller - I've never seen a pot smaller than that. If it turns out the roots were rotted you can either change the mix to a little bit more porous, or water less often. But you will also need to keep the humidity up and keep it from drying out so new roots will grow.

Does your 20-20-20 have any calcium or magnesium in it? Often they only have N-P-K, and if you use rain water with something like that the plant is not getting optimal nutrition.

[Judi]

Yes, the fertalizer has .02% boron, .05% copper, .10% iron, .05% manganese, and .05% zinc. The Ph is around 6. I also use a little K-L-N once a week. You're right about the pot, I wasn't able to find a smaller one. I think the best I could do is to stay with this pot or make one by cutting holes and slits in a small plastic fruit juice cup. I will have to get up the nerve to repot--if there are very few roots, do you suggest sphg? I don't use it myself but I did have luck with it once with a phal that lost all its roots. For a healthy small paph like this, what size should healthy roots be, I mean how thick?

[slipperfreak]

I recommend using tap water with your fertilizer to supplement calcium and magnesium. I would also check your city's website for a water quality report to see how much of these minerals is in your water. If your tap water has under 40 ppm Ca and 20 ppm Mg, I recommend adding 1/2 tsp crushed oyster shell to the pot, and mixing 2 tsp epsom salts to 1 gallon of water and fertilizer once every few months.

The roots of a Paph this size would be quite thin, but I wouldn't be too worried about that. I would be more worried about them being rotten. If they are rotten, I WOULD NOT plant in pure sphag, but rather in a fine bark mix with small pieces of bark, charcoal, and perlite that has quite a bit of moss added to it.

Hope this helps.

[Judi]

I started using rain water years ago before I got into orchids because I have well water that is very hard and left too much residue in the soil. Hardness is 240 mg/l; calcium is 88 mg/l; and magnesium is 20 mg/l. I flush all my chid under running tap water (unsoftened) once a month. Do you think it would be a good idea to alternate well water with rain water? And just out of curiousity, what is the physical benefit of calcium and magnesium? Is it necessary for all orchids or mostly for paphs?

[weez1959]

when you repot, can you post a pic of the roots?
I'm about to repot one myself...
Inquiring minds (mine mostly ) need to see

[slipperfreak]

Originally Posted by Judi

I started using rain water years ago before I got into orchids because I have well water that is very hard and left too much residue in the soil. Hardness is 240 mg/l; calcium is 88 mg/l; and magnesium is 20 mg/l. I flush all my chid under running tap water (unsoftened) once a month. Do you think it would be a good idea to alternate well water with rain water? And just out of curiousity, what is the physical benefit of calcium and magnesium? Is it necessary for all orchids or mostly for paphs?

That water is not much harder than mine (mine is 220ppm, mg/L), and I use exclusively tap for all of my Paphs. I would recommend using well water when you fertilize; that way your plants will get it every week and they will get Ca and Mg with your fertilizer, making a complete nutrient package. With this method you shouldn't need to add anything to your potting mix.

Ca and Mg are both lesser macronutrients; they are required in smaller amounts than N-P-K, but much larger amounts than the micronutrients (such as Na, B). They are required not only by all orchids, but all plants, for survival and growth. Some plants require more calcium than others, however. Roughly half to two-thirds of all Paphs are calcicolous, meaning they like extra calcium (they grow naturally on substrates rich in calcium). Paph moquettianum is one such Paph. The catch with calcium and magnesium is that in too high amounts (as with any mineral), they will burn the roots and leaves of your plant. So I would try using tap water with your fertilizer for a while, and if the plant doesn't show signs of improvements after a month or two, consider adding Ca and Mg supplements as I described before.