Phal Culture in Houston

[AgPatt]

Hi everyone!

I've been lurking around OB without an account for a decade. More? I never felt like I needed one because someone else had already asked my questions and I could just read the answers on their thread. Until now.

I grew windowsill NOID phals in NC and AR (both zone 7) for 9 years. They were easy. They never died, even those that I bought nearly dead already. And, they bloomed profusely. Then, nearly 6 years ago, I moved to Houston. Cattleya and dendrobiums may grow like weeds here, but since then, my phals have dropped off one by one. An annual bloom is far from certain. And, even the survivors are far from thriving.

Is anyone getting phals to thrive in Houston or similarly humid zone 9 conditions? If so, how?

[Dimples]

How were you growing them? Knowing what didn’t work for you in your new location will help pinpoint what problem(s) contributed to their demise.

I’m in Fallbrook, zone 9, north county San Diego, and my phals (~20 +\-) are in medium bark in plastic pots with varying amounts of ventilation holes. They get watered as needed, but at least 2x a week in my conditions, up to daily depending on how new the bark is, pot size, and how warm it is. My phals get high light levels from an east and south facing window set, around 2,500FC maximum on clear days. I also use a couple heating mats December-April to boost the root zone temperature.

Our annual indoor conditions are no lower than 64F, no higher than 88F, and average RH 45-65%. Our humidity can drop much lower during a Santa Anna, but it’s temporary. As soon as we close up and turn on the humidifier it goes back up.

[AgPatt]

I don't know if my answer will be super useful since I can't give a quantitative answer for most things. If you need FC, RH, or PPM, I simply don't know. That being said, in NC and AR, I grew them in straight horse manure, sometimes in terracotta, sometimes not. I watered daily in terracotta, weekly in less breathable containers. I used tap water. I put them on a shaded northern deck or inside a northern window, depending on temperature.

In Houston, I don't have access to horse manure. I tried semi-hydro. I tried water culture. I tried sphagnum moss. I tried bark. I use rain water, Better Gro fertilizer @ 1/8 tsp per gallon, garden lime @ 1/8 tsp per gallon. They're still on a shaded northern patio or window depending on temperature. I should probably clarify that I didn't put every phal into all 4 of these growing media in under 6 years. But, across the group I've tried all 4 and as I said even when they aren't dying, they aren't thriving. I've also tried a handful of different supplements none of which seemed to make a huge impact either positive or negative.

Hopefully, I answered everything?

[Dimples]

I’m not familiar with using horse manure for anything except as a soil amendment, but I ride so I’m familiar with the general properties of horse manure. I’d guess the older aged stuff would have water holding characteristics similar to moss or chunky peat depending on how packed it is?

Anyway, what you did in the other places isn’t working for you now. What symptoms are you seeing? Root rot? Root desiccation? Leaf loss? It could be less to do with the medium and more to do with your watering frequency. I have my phals set up so I can water them nearly as often as I want without worrying, because the roots are in a very airy environment. Phals don’t want to dry out but the roots do need lots of air.

Also, 1/8th tsp per gallon depending on the application frequency may not be enough fertilizer. I’d be using that every time I water with only the occasional plain water flush.

As for light, two identical north facing patios in different locations will provide different results. If one is across from a large light colored building it will have higher light levels from the reflected light off the other building. A thick bank of trees in place of the building will have the opposite effect. Do you have any other plants in the same spot that are doing ok?

[AgPatt]

There's a dendrobium nobile doing well there. Most of the phals I lost had some type of rot be it root, collar, crown. These 10 survivors don't look super healthy. Four are just not blooming this year. The six that are only have a few blooms, which isn't how they used to behave. A couple of them have leaf discoloration like they may have a nutrient deficiency.
Actually, between your comment about the fertilizer and reflecting on this, they may all have a nutrient deficiency and it's just further along in those that went into inorganic media. FWIW I am fertilizing every time I water, currently. But, my son turns 2 in May, so they had about an 18 month run there where feeding was VERY inconsistent. Will this current fertilizer rate be enough if I keep it up weekly? Or should I do more to catch up?

[Dimples]

If you suspect a nutrient deficiency as the most likely cause, I’d be upping the dosage for awhile. Maybe try 1/2 tsp per gallon for a few months and use it at every watering.

I don’t use Better Gro fertilizers, but a quick google search showed me they have two formulas labeled as “orchid fertilizer”. If you’re using the high phosphorus bloom booster formula, I suggest switching to something else at least temporarily. High levels of one nutrient can interfere with the absorption of other nutrients, and deficiencies can develop even if the plant is technically getting everything it needs.

Rain water isn’t required for phals. Mine do fine on our municipal water (from the CO River) so long as I water copiously. They can even benefit from the extra calcium and magnesium. Which, if your fertilizer formula doesn’t contain enough calcium/magnesium and you’re using rain water, THAT could definitely be a problem over time.

[Ray]

Every time you changed the type of conditions the plants were in, they were going to need to grow roots attuned to the new conditions, as the plants would be expected to lose their existing roots.

High heat, and high humidity - to me - sounds ideal for phals.

[estación seca]

Welcome to the Orchid Board.

Phals are full shade plants all year. Houston sun will cook them.

Your problems will be related to hot and humid in warm weather, and cold in winter. In warm weather be sure there is a lot of air at the roots. Water frequently so the roots aren't dry for long, if at all. A dense medium like horse manure will suffocate roots. Keep water out of the crown.

In winter keep them warm. They don't like cool at all.

[Gardening in WM]

I agree with Estacion.

But it could be a variety of different reasons.

Dendrobiums and Cattleya's grow well with you you say - these can tolerate colder temperatures than Phals so it might be as simple as you are keeping your phals too cold in winter. You might have even read this is beneficial for phals but phals are tropical plants that require warm temperatures all year. They are light sensitive orchids.
You might have read that reducing temperatures below 65 F degrees will cause them to spike and although that is true, it only happens because you are causing the plant stress. It is not something I personally would recommend anyone does on purpose. Orchid nurseries will do this to get their plants to flower so they can be sold better but it stresses the orchids and they might sulk for several months afterwards as a result. It is best to grow them warm and let the seasonal light changes dictate when it is best for a phal to flower. A healthy phal will flower much better year after year if grown warm all year long (under 80 F) opposed to one that you force to flower by lowering temperatures below what they would experience in nature in a tropical climate. If it is done at exactly the right time of year it can be beneficial but otherwise it will just cause stress and confusion for the plant.

so it could be the low temperatures causing stress.

I believe the dolomite lime could be another potential problem. Dolomite lime raises the PH of the media a lot. Phals like acidic conditions. This can lock out nutrients. Dolomite lime can also contain lead and although other houseplants can tolerate trace amounts of lead, orchids are very sensitive to heavy metals and it will stress them far more than other plants. Many growers have experienced problems using dolomite lime not just with orchids.

A better solution is to use calcitic lime and epsom salt.

Or a cal-mag fertilizer is the best option as it is safe, chelated and contains beneficial iron added too.

You used to use tap water and horse manure and had excellent results.

Then you switched to rain water and started adding the dolomite lime to compensate for rain water not containing enough calcium and magnesium which is when your problems started.

Maybe just stick to tap water which contains enough calcium and add 1/8 tsp of epsom salt/gal to add the missing magnesium

If you cannot find horse manure and you liked the results you can substitute horse manure for chicken manure which is much easier to find.

But in your climate you should be growing them indoors where I would not recommend using chicken manure as it smells.

So my nr 1 tip would be to ditch the lime and substitute it for epsom salt + tap water or epsom salt + calcitic lime + rain water. Then again if the lime is not causing any problems fro the dendrobiums or cattleya's it would indicate it could just be the wrong temperatures and possibly like estacion has mentioned too much light for them as a zone 7 will be much brighter than a zone 9.

[Dimples]

Quick addition about chicken vs horse manure in the states. So long as the urine isn’t mixed in with the manure, horse manure is primarily partially digested hay with limited available nutrients. Almost all of the nitrogen and other nutrients are excreted in their urine, leaving the manure rather benign.

The same cannot be said for chicken manure. Everything exists the bird from the same opening, so chicken manure contains all the nitrogen and other nutrients, and is considered “hot” and needs composting before use, unless it’s being mixed into a considerable amount of garden soil. Even then it’s typically best to let it sit for awhile before planting into the prepared area. Composted chicken manure available at stores and bulk sellers is far too fine and too nutrient dense to be used by itself for epiphytes.