Hey al, I have a seedling mat that i bought (just a cheap one) no thermostat. i have a barrier between the mat and my seedling tray, but i turned off the mat and within 12 hours of doing so every r/w block i had in there showed healthy roots popping out. My question is, is it even worth having the cheap one on? or just ditch it? (i never throw anything away, i plan to use it at the bottom on my micro cab that i am converting into a bud dryer to add a little heat. the box has intake and exaust fans with one oscillating fan inside it. sound like it will work?) thanks for any input ^_^
Heat mats which do not have an adjustable thermostat normally still have a thermostat but it is fixed at a particular temperature, usually 30C. Confirm the surface temperature of the mat by putting an indoor/outdoor thermostat's outdoor temp sensor in contact with the mat surface (a bit of box tape to hold it in contact with the mat surface is necessary).
You can add an external thermostat to your heat mat. Most hydro & many general gardening shops sell thermostats which have an external temp sensor (often the mercury bulb type) which can be fixed down to the surface of the mat, again with a bit of box tape. Such thermostats incorporate a switch for controlling an AC mains powered device, such as this unit from Growlush:
A thermostatic controller like this will allow you to be certain of what the surface temperature of the mat is running at.
I would not use a cloning heat mat in your bud dryer. They are not designed to heat air; they're designed to put a small amount of heat into objects in contact with the mat, such as rockwool cubes.
That your clones popped after removing the heat mat sounds coincidental. There's an awful lot of variables in cloning and it's a rather fiddly process. You have not given me enough details to diagnose precisely what happened in your particular situation.
Heat mats are used broadly in horticulture due to their well-known & proven effect of speeding rooting of cuttings and seedlings. If the temperature is well controlled, they are a very useful adjunct in cloning. I consider them to be essential in a SoG op due to their improvement of speed of rooting. With a heat mat, you should be seeing first roots out of the bottoms of 40mm cubes in 7-8 days (and even quicker on occasion). Without a heat mat, that period will roughly double and will not be nearly as consistent. Heat mats vastly improve the predictability of rooting time.
So should I add that 10-15 grams of water back to the cube?
Isn't that what you're doing when watering the cubes every 12 hours?