Keeping potting medium warm? - Orchid Board

Shyulace · #1 03-30-2011, 07:28 AM

Hey everyone,

I'm still pretty new to growing orchids and getting their environment right. Right now since winter is almost over so this problem shouldn't be occurring for that much longer, but I have trouble keeping my potting medium warm especially after watering. I heard that having a cold potting medium would be very bad for most chids.

My current situation is that my house is probably only warm from 5ishPM - 12ishAM because thats when the heater kicks in. For rest of the day my room is kinda chilly which results in a cold medium.

I try watering my plants with warm water and when my heater kicks in but thats as much as I can think of doing short of buying an induction room heater which eats up energy like mad.

Any other suggestions? Thanks

Discus · #2 03-30-2011, 07:37 AM

It depends on the plants - some orchids will probably enjoy having cold(ish!) roots, whilst other will hate it.

Some people advocate using heating mats under their pots; more tropical plants will probably quite enjoy it. I seem to recall Ray from firstrays raving about the benefits of bottom heat.

Heating mats don't use up all that much power - some may be available that are thermostatically controlled and can be set to whatever you want - I have a propagator that is permanently set to 19ºC, which I currently have a bunch of seedlings in - I'm sure they'll appreciate it as we're moving into winter.

As with all things orchid related, it depends on you, your plants, and your microclimate

Shyulace · #3 03-30-2011, 07:59 AM

Oh thanks for the link!
I coincidently do have a propagation mat but I wasn't sure if that would provide sufficient heat to the container. I know the clay pots I have wouldn't hold/receive much heat compared to plastic containers. However what about if its a container with slits in the side as well? I figured the air movement would take out all the heat.

But its better than nothing

Thx again

Ray · #4 03-30-2011, 08:31 AM

The mats I carry (designed to fit in a standard nursery tray) only consume 17W, and boost the root zone about 10°-15°F over ambient.

If that's not sufficient, you should focus your attention on cool-growing plants!

Discus · #5 03-30-2011, 09:49 AM

Quote:

Originally Posted by Shyulace

Oh thanks for the link!
I coincidently do have a propagation mat but I wasn't sure if that would provide sufficient heat to the container.

It should work just fine - and don't worry too much about the clay vs. plastic thing - you should find once it's warmed up to the same temp. as the heating mat, the clay pots will stay warm just fine, even if it takes a while to get there!

I suspect the "warm bubble" of gently rising air from the heating mat is also something the plants like.

You should however let us know what plants you have - some will, I suspect, hate bottom heat (many pleurothallids and other cool-growing orchids) whilst many intermediate to warm plants will enjoy it.

Shyulace · #6 03-30-2011, 02:47 PM

Hey Ray, I have the same Hydrofarm mat you have described on your website that I use for seedlings that I got a while ago. I'll try it out and see how that works out. I didn't think that would suffice for orchids with a fan running for circulation.

Discus, I currently have a few phal noids from HD which are recovering roots. But I haven't seen any new growth lately.
I also have a phal equestris, phal pulcherrima var chompornensis, and brassia Caudata seedlings. I assume they would all benefit from the added warmth right?

Just thinking, would it work if I dropped a small aquarium heater into the humidity tray? I figured that would help since I don't think it would be as effective to have a heating mat under a humidity tray and then plants on top.

I'll just try both out I suppose and compare :3

tree1 · #7 03-30-2011, 02:54 PM

This is interesting as I've just started with orchids and it's spring, the temp in my house is just over 20 degrees C, but in winter this will drop much lower at night and I can't afford 24hour heating bills!

Discus · #8 03-31-2011, 05:08 AM

Yes, bottom heat should definitely help your rooting phals and your seedlings - as Ray says on his site, bottom heat is a long-established, effective method of spurring plant growth (particularly seeds and cuttings) - and appears to work well with orchids in his experience.

I've been considering a similar idea to your aquarium-heater-in-water warming plan for an orchidarium one day - that will also help boost both the heat and humidity around those plants.