How to Control Temperature?
 

Hi all, the temperature in my area has been dropping very low in recent nights (10C/50F), which I'm afraid may be affecting my phals.

I've tried seedling mats, but they heat up the area very minimally (only 2-3 degrees F).

I've also tried ceramic heaters, but the plants closest to the heater tend to become very hot, while the ones further away don't experience much of a temp increase. Ceramic heaters also tend to draw a lot of humidity from the area.

Are there any other ways to raise the average temperature of my phals? Right now, they're all huddled together under a grow light in a corner of my room.

It all depends on how many plants and their size.
Can you give us some more info?

The heat mats probably keep the pots and roots warmer than the air, so they do help. You could cover the plants at night with a blanket or sheet to hold the heat.

Phals. survive cold periods better when very dry, with fine wrinkles in the leaves. I sometimes give Phals. in my house only 2-3 waterings over winter, during warm spells. These waterings are often no more than a few sprays with a spray bottle.

Seedling heating mats don’t warm the area around the plants, it warms them directly like ES said. All my phals. are on seedling heating mats. They are quite effective. Give them another try.

Like said above, don't be too quick to discard the seedling mat solution. Many professional growers (and not just orchids/ warmth loving plants) actually use bottom heating so that they can maintain a lower air temperature in the greenhouse. Root zone temperature is far more important than leaf temperature for plants (though there are limits to this).

You can also invert a plastic storage bin, or even a cardboard box, over the plants at night to help trap a bit more of the heat generated by the mat.

Thank you very much for the replies! My collection is a mix of large grocery store phals and a couple small ones that are still growing.

The grocery store phals are in thick, 5" ceramic pots. I've stuck a thermometer deep into the soil before, and it was around room temp (10C/50F). This is with the heat mats.

The smaller phals are in 2" plastic pots. When I stuck a thermometer into the roots, I've found that the mats only heat it a couple of degrees warmer.

Because the larger phals are in bloom, I can't cover the entire collection with a sheet or box to trap in the heat. If anyone has any ideas, please let me know!

My question related with the quantity and size of your plants is because, if they are many, solutions like covering with plastic or any other material is difficult (I think). Also, the volume to be heated might be more or less large so you'd better find ways to heat the entire room or finding another place for the plants.

Or maybe those temps won't last long... keep an eye on weather forecast.
As a side note, last winter my Phals experienced temps of 12ºC for days in a row when there was no sun and what I've noticed was a profusion of flowers higher than usual.
As your plants are large grocery store Phals, probably they will be more resistant than a species would be.

I don't know how much room you have, but maybe a Martha tent would be the answer to your problem. They come in various sizes. The one I started out with has a footprint of 2ft x 3ft. The one I have now is 5 x 5. The addition of a small heater and humidifier, along with the appropriate controllers, will allow you to keep your plants in the conditions you choose.

To better control the temperature for your phals in the cold weather, consider using a combination of strategies to achieve a more even and stable environment. An option is to use an infrared heater with a thermostat to maintain a consistent temperature, as infrared heaters distribute heat more evenly without drying out the air. Additionally, you might want to use a humidity tray or a humidifier to counteract the dryness caused by the heater, as maintaining proper humidity is crucial for orchids. Another effective approach is to use a propagation box or mini greenhouse with a heating pad specifically designed for plants, which can help maintain a warmer and more consistent temperature around the phals. This setup helps in creating a microenvironment that keeps the temperature more stable and suitable for your orchids.