Grow Mediums seedling heat mats under autopots

[BII]

No evidence yet, but I'm doing it now. Started all 8 plants on Friday. But what about the evidence that a seedling heat mat helps seedlings? There is some evidence. I'm taking that a bit further though and will do it up to at least day 20 so well in to grow. Once I turn on the autopots, then that's a different story.

I do run inlines in and exhaust. 4 inch in, 8 inch out. The garage is cold inside in the winter and the inline fan brings in cooler air to the tent. I have speed controllers on both fans. Not thermostats. I adjust them manually but more to control humidity. If in growth mode I like to dial in VPD to the sweet spot which I do by adjusting the humidifier output and by how fast the exhaust pulls that out. It's a totally observe and react kind of thing I do.

I would presume optimal temperature is way way more important, critical, than optimal humidity. Also, it makes much more sense to have both temp. and humidity under actual/full control. Why not run the exhaust/intake ventilation by air temp. (thermostat) and then set/adjust your humidity (with the humidifier similarly kept at a set value by sensor feedback)? Currently, you have adjustable/controlled humidity but problems with temp.

With your problem being temperature, doesn't a thermostat make sense? You'd retain more heat (and humidity), if your exhaust ran on a thermostat, was not constantly pumping out heat from the lights. Also, you currently lose any CO2 benefits from your in-tent oil heater if you just endlessly exhaust air (and obviously too much air, since you have temp. issues). Also, with intermittent vs. constant air exhaust/intake, your humidifier would run less.

I use a Lux WIN1000, with the exhaust/filter fan coming on with every raising of temp. 1 degree above my set temp. and turning off the fan when 1 degree below my set temperature. Can' get much better temp. control.

 

[lunarman]

I would presume optimal temperature is way way more important, critical, than optimal humidity. Also, it makes much more sense to have both temp. and humidity under actual/full control. Why not run the exhaust/intake ventilation by air temp. (thermostat) and then set/adjust your humidity (with the humidifier similarly kept at a set value by sensor feedback)? Currently, you have adjustable/controlled humidity but problems with temp.

With your problem being temperature, doesn't a thermostat make sense? You'd retain more heat (and humidity), if your exhaust ran on a thermostat, was not constantly pumping out heat from the lights. Also, you currently lose any CO2 benefits from your in-tent oil heater if you just endlessly exhaust air (and obviously too much air, since you have temp. issues). Also, with intermittent vs. constant air exhaust/intake, your humidifier would run less.

I use a Lux WIN1000, with the exhaust/filter fan coming on with every raising of temp. 1 degree above my set temp. and turning off the fan when 1 degree below my set temperature. Can' get much better temp. control.

At one point I was running all HPS. 1200 watts. And I didn't really have a heat problem in the winter. But I sure did in the summer. I had a thermostat on the exhaust fan but it didn't work well so I switched to speed control. I should revisit that now that I have LED lighting. Environmental controls have changed on me a bit with the light change and the reduced temps that go with that.

 

[puffer1958]

Living like in a northern climate. Winters are long and harsh. Indoor growing but in garage that is colder than a house thats for sure. its insulated but not heated. I have to run quite a bit of heat in the tent (oil heater) to get 25C ambient temp during the winter. I do have a slab of chip board between the concrete floor foundation and the tent floor too. Also 8 inches of insulation batting on the top of the tent.

And of course I'm looking to get that little bit more towards better grows. And reduce electrical bills too for that matter.

I have totally ignored soil temperature but now I'm thinking this is something to look at. I started with one seedling mat under two pots with new tap rooted seeds and although I have no hard data I feel its making a difference after a week. So I bought 3 more mats for a total of 4. I run 8 autopots. Right now its too early for the irrigation trays and valves, but once I add them in at day 20ish, the worry is the heat might to too much for the nutrient feed in the trays (Mega crop).

I know about the thermostat controller for heat mats. But not sure how to proceed now. Maybe buy a thermostat for one mat to compare against not having control and see how the plants react. Also thinking it would be smart to measure the temperature of the water in the trays. But what would the ideal temp be for water in the tray? Or should I measure the temp of the roots at the bottom of the tray?

As far as root zone temps, I have had many rdwc grows and use a bluelab meter to monitor pH/temp/ppm and from everything that I have read root zone temp begins slowing growth at around 62f

Its a garage and it is insulated. Not sure what R factor, but I know it's not up to a house standard. So what's done is done and not much I can do to improve what is already there without tearing it out. I know the tent needs heat and all that and the expense of it. So I started thinking of localizing the heating I'm doing right at the root zone. Put a heater right under the plant basically.

If you have humidity on the higher side you can put a dehumidifier in your tent which gives you the ability to control humidity but also raise tent temperatures quite nicely for much less power $$ than most space heaters (oil, ceramic, resistance,etc). I speak from personal experience in a very similar set of circumstances. They can be bought very affordably on FB. I just sold one that way myself a month ago to raise a little fun money for a Denver trip, yeah buddy. I would say that you could pick up a used one on FB local "yard sale" page or FB marketplace for $50 or less and they are handy and critical(sometimes)for household emergencies. More personal experience.