Short flower spikes on Phalaenopsis

[Ray]

Originally Posted by dch53

- 1 part horticultural charcoal (not the same as charcoal for barbecues). Note: This ingredient is extremely important as it neutralizes fertilizer salts.

That, unfortunately, is misinformation.

Charcoal does not "neutralize" anything, as that requires a chemical reaction. At best, it adsorbs ions from the solution, trapping them, but that (sort of a quasi chemical reaction) is limited, as a reasonable level of adsorption requires the charcoal to be activated, and horticultural charcoal has not been treated enough to create sufficient activated sites.

Charcoal, being porous, does absorb liquids, and upon drying, the dissolved solids will precipitate in the pore structure. Unfortunately, as that wetting/absorbing/drying/precipitating process is repeated, the salt buildup becomes more extensive, becoming toxic over time.

The primary function of charcoal in the mix is to maintain airiness longer, as it doesn't decompose as rapidly as bark, moss, etc.

[Kittyfrex]

Originally Posted by Ray

That, unfortunately, is misinformation.

Charcoal does not "neutralize" anything, as that requires a chemical reaction. At best, it adsorbs ions from the solution, trapping them, but that (sort of a quasi chemical reaction) is limited, as a reasonable level of adsorption requires the charcoal to be activated, and horticultural charcoal has not been treated enough to create sufficient activated sites.

Charcoal, being porous, does absorb liquids, and upon drying, the dissolved solids will precipitate in the pore structure. Unfortunately, as that wetting/absorbing/drying/precipitating process is repeated, the salt buildup becomes more extensive, becoming toxic over time.

The primary function of charcoal in the mix is to maintain airiness longer, as it doesn't decompose as rapidly as bark, moss, etc.

To be fair, charcoal has some antimicrobial properties, but how much that helps an orchid is beyond me.

[dch53]

I ordered the bark online and they pieces are a fairly uniform 1/2 inch or so in size.

I read somewhere that you can judge whether the pot needs watering by feeling the weight when you pick it up but that's never worked for me because the potting mix is so light. I tried a hygrometer and that tells me that the pot is dry a couple of days after soaking.

Soaking for an hour once a week seems to work. I do soak them for longer during the summer.

[Dimples]

Don’t forget that new bark will hold onto less water compared to the old medium. You may need to water more frequently at first.

I give newly repotted phals. a long soak in water, at least an hour. Often 3-5 hours, because I forget about them. It helps break in the bark.

[Kittyfrex]

Originally Posted by dch53

I ordered the bark online and they pieces are a fairly uniform 1/2 inch or so in size.

I read somewhere that you can judge whether the pot needs watering by feeling the weight when you pick it up but that's never worked for me because the potting mix is so light. I tried a hygrometer and that tells me that the pot is dry a couple of days after soaking.

Soaking for an hour once a week seems to work. I do soak them for longer during the summer.

If that's the case, you can try mixing some sphagnum in for water retention. At this time of year, i water about once every two-three week, even less before spikes emerge.

Also, the weight is a good way to measure how wet it is but works only on water retentive media. Bark does hold onto some, but not nearly enough to notice a consistency.

[dch53]

Great. Thanks again.