I think that the goal of running humidity "as high as you can to keep plants happy" is perhaps not the best approach to providing a growing environment for your plants. The 60% I mentioned above is *not* a target, it's the maximum allowed. If it stayed that high all the time, there would be problems with mold and peeling paint. At the moment, with some sensitive plants as temporary houseguests, I feel much better when it's around 50-55% for several hours a day, with the aforementioned dry-off period every night. I tried to mimic, if not duplicate, greenhouse conditions in my grow room for the first few years. I was convinced that with my HID light that my plants would just shrivel up if they weren't getting constant high humidity. But you know what? Finally I got so sick of cleaning my fogger that I tossed it out and thought, if the orchids don't like it, let 'em die. Guess what? They went right on, and I'm having more flowers now than before because I'm buying plants that are appropriate for the conditions that I can apply without breaking a sweat, and all that attention to humidity has been directed to other considerations. At the moment, I have three sensitive plants that I want to bring into bloom, enjoy, and move on so I'm paying more attention to humidity. After they're gone, I MAY run one humidifier in there to keep things above desert conditions while the heat is on - I'd be happy with above 40%. In the spring, I'm just going to ventilate the room and forget about humidity. J

Kevin. Ok when your back from the paint... LOL. Whatcha painting? I didn't go to church this morning. "Carla" went to church and I wrote ;-) Not a challenge but rather fuel for debate to sort it out! That's the forum,. Interesting to learn & better than an oncid. stake in the eye on a Sunday afternoon :-) "I would assume it's rather balanced, but since there's more rain at certain times of the year more nutrients are available at certain times of the year." That's my POV and question for the forum. I think they change due to those very factors at certian times a year. I am not a Geologist. Studied Pharmacology on a graduate level. Still way out of my range to know the molecular specifics (or to really care to know). When I can't get the gunk off in the car wash at certain times of the year something has changed. Maybe a tree sapping, maybe salt/minerals, maybe both or something else?? But there is some kind of change. Does it contribute to nutrient balance? I imagine it could. Just like you can smell Fall coming, people who live is sub-tropical climates are attuned to other changes. (Like car gunk and mouthfuls of salty air) The earth is a big chemistry lab. It goes through seasonal cycles. For orchids we are talking micro nutrients. There has to be some reason why High P and High N Ferts are offered and recommended at certain times in a cycle? I suppose that's my really question besides when is why? Not sure about what you mean about ambient moisture? I don't think that RH has a whole lot to do with nutrition. (Did I catch your meaning right?) There are months in Miami where there is low RH, Jan, Feb March. Feels normal, like Chicago in Spring, believe it or not. There is only some much folar feeding that can go on. After that, the plant just starts to rot, just like they do in our homes when we mist at them too much or it rains too much. Saw that a lot in Florida. Scrappy wild 'chids. Besides wild-life munching away, there is rot in situ. They ALL need "re-pots", Physan and Safer's :-). If you live on the coast, the car gets a fine coat of ocean salt. Is it something orchids need? Probably not. They just get a little crusty and need a hosing if the air becomes still. I was careful not to say "everything". But the earth is connected. The currents of the oceans, those earth cycles, play a large role in weather. Weather and seasonality may have a role in dictating nutrients. When snow is released into the water supply there is certainly nutrients that have been locked away and are now available? Hurricanes and Monsoons screw up the drinking water. The water supply in my city gets an adjustment after a particularly bad winter. Global issues affect the entire planet, not just the source...Right? Is that your area Kev? If so, SOS please Pleuro's nutritional needs are not as demanding as other species. Their location could be dictating that? Its very stable, compared to a FL Encyclia. But it's still is not the misty sauna that you might imagine at certain times of the year just like Miami isn't, but that is relative when you live in a place like that. 30 or 40%% humdity is low RH. Medellin Colombia's weather can be similar to Ca. It is "La ciudad de las flores"! General fert.is fine. I've used it. I don't have it right now. When I go to the sink, I have no idea what to "cook" for them. This is one of those times. I am like everyone else. I have limts with the orchids and what I am going to concoct. I don't cook individually for 200 people. But I will give them something they like from the menu, en masse. If I didn't have the orchid hospital, there would be 1 kind of fert. being used at certain times of year. But then again, I use high N on them because they need vegitative growth and the others don't. My goal is not to flower them yet. See where I am getting confused? I would like flowers for the holidays from the healthy ones. Would be nice to understand when, who and why :-) Let me know what your 'second coat" thoughts Clara Should have gone to Church with "Carla"

I realize that this is an old thread, but folks may review it in the future and benefit from the discussion. Indeed, there is another, recent, similar thread on low indoor relative humidity in a Minnesota home in winter, so it worth correcting some of the misinformation on this thread. "Again and hopefully for the last time you can not dehumidify with a single stage AC to any large extent. It will always over cool, long before it dehumidifies to any large extent." A properly-sized air conditioning system-- including single-stage systems-- will dehumidify air whenever the air temperature leaving the coil is at or lower than the dewpoint temperature. In the summer in my (mixed-humid) climate zone, that's most of the time. I have a single-stage air conditioner. All of the water being drained at the end of the condensate line is ample evidence it's dehumidifying. In fact, it creates a wet spot in the lawn that I need to reseed every fall. When my air conditioner doesn't do an adequate job of dehumidification is during so-called "shoulder seasons" when there is no real demand for cooling (you can't dehumidify if it's not operating.) We get shoulder seasons for three or so weeks each spring and fall. For shoulder seasons, I've found dehumidifiers to be the right complement to my air conditioner. I have one on each level of my home integrated into the HVAC system. They enhance comfort, and they reduce the potential for mold/mildew which is very common in our climate zone. They can also be configured to introduce fresh air into a home, which is a plus, year 'round. "Just because an AC can't dehumidify a high humid situation, doesn't ever mean it is over sized... because the single stage AC wasn't designed to dehumidify. It was designed to COOL" Not so fast. An air conditioner, as the name implies, is part of a system which maintains comfortable indoor conditions for the occupants. It cools, dehumidifies, and moves air throughout the home. The dehumidification part is stripping moisture from the air. Indeed, when designing an air conditioning system, we need to consider both the sensible cooling load and the latent (moisture removal) loads. A properly-sized single-stage system can dehumidify air. Its ability to do so is affected by run time under particular conditions, which is a sizing consideration.

Ray, Less than ideal doesn't imply something won't work, it simply means there are better options if you want a zoned system. I had a single-stage heat pump and fixed-speed air handler for HVAC on the 2nd floor of my previous home. It was a zoning retrofit that provided two zones of control. It worked for 15 years until the heat pump gave out and then for another three after the heat pump and coil were replaced. It was less than ideal. The variable speed two-zone control system on the 1st floor was better. That system wasn't a retrofit; it was a brand new system with all new duct work. I'll make an attempt to answer the air flow question for you one more time, Ray because I don't want you attempting to design or sell someone a system without knowing the basics. A single-speed air handler isn't a variable speed air handler like your beloved Bosch inverter. It produces air at a single flow rate depending on the blower's fan curve. The more pressure drop, the less flow. Consider a two-zone system where the cooling load on each zone is equal (i.e. 50% of the total load.) When only a single zone is calling for cooling, a fixed-speed air handler will direct all the air flow it can produce into that zone. In this case, 100% of fan capacity for only 50% of the cooling load. The amount of air flow won't be fully 100% of the system's normal air flow due to the additional pressure drop compared with both zones open and calling for cooling. So there's an excess air issue. That means too much air, Ray. To deal with the "too much air" issue a bypass is typically installed. It recirculates a portion of the air leaving the coil back to the upstream side of the coil in a continuous loop. The temperature of the air entering the coil gets reduced, and continues to get reduced as the zone approaches set point temperature. There's not enough load on the coil and it's at risk of freeze up because the air flow in a single zone is less than the full air flow rate the single-stage compressor and coil are designed for. That's the too little air flow part. Variable-speed and multi-stage compressor systems are much better for zoning applications than single-stage, fixed-speed systems because they can adjust the air flow and the cooling to match the actual load. By contrast, single-stage compressors and fixed-speed systems are less than ideal.