Phal leaf issue

[Setter]

Several of my Phalaenopsis have leaves that look like the attached picture. I grow in semi Hydro, the day temperature around 85° night temperature around 70°, good airflow and humidity around 65%. Does this look like a nutrient deficiency?

[estación seca]

What water are you using? What fertilizer? How often?

[Setter]

RO water. MSU K-lite fertilizer, filing reservoir every week.

[Ray]

Originally Posted by Setter

RO water. MSU K-lite fertilizer, filing reservoir every week.

K-Lite at what concentration?

Filling only, or flushing to refill?

[Setter]

1\8 tp per gal. I don't flush each time I water. I do water until water runs out the 2 holes at each watering. I do a complete flush, water to the top and drain out the holes, once a month.

[Ray]

1) I suspect you’re under-feeding. 25 ppm N is fine, but my plants in S/H culture get that 2 or 3 times a week.

2) When you water, you should always fill the pot rapidly to the top and let it drain down to the holes, as that flushes residues, wets the medium, and refreshes the chemistry of the reservoir. Doing so precludes the need for your monthly plain-water flush, too.

By merely topping it up, you’re letting the plant sit in a combination of fresh solution and it’s own wastes.

[Setter]

Thank You!

[estación seca]

I'm suspecting a magnesium or iron deficiency if you've been feeding it that sparsely. Mg is a constituent of the chlorophyll molecule, and Fe is necessary for its synthesis. You can add a half teaspoon of Epsom salts to your mixture along with the Klite for the Mg. It can take months to give enough Mg to a deficient plant.

Look for a water-soluble iron supplement and add a tiny amount.

You don't need to use R/O water for most Phals. Where do you live? Using tap water is fine for Phals in most of the US, and you will not need to worry much about mineral deficiencies.

[Setter]

I live in Northern Nevada. We are on well water. The TDS is 168. The ph is about 7.7. Is this water ok to use on my Phalaenopsis in SH?

[estación seca]

I dream of having tap water with TDS that low. You can use it on most orchids other than cloud forest species. Check the pH after mixing your fertilizer. You can get a pH test kit at an aquarium shop or swimming pool supply. You are aiming for pH around 5.5-6.5.