I'm writing this with newbie propagators in mind, who want to use bottom heat to grow cuttings, or germinate seeds using a Heat Pad. In order to make the job as foolproof as possible, I'd suggest using a heat pad with inbuilt thermostat. If we were to use the Heat'n'Grow Range of pads as examples of what's available, we start off with the following. The numbers listed are the wattage of each pad.
TPS 020 is a single tray unit.
TPS 040 is a double tray unit
TPS 080 is a four tray unit.
TPS 020 is a single tray unit.
TPS 040 is a double tray unit
TPS 080 is a four tray unit.
https://heatngrow.com.au/
No matter which of these you use, the principal is going to be the same and although it sounds easy to sit a tray of seed raising mix on the pad, you've really got to know a bit about growing with bottom heat in the first place. With all three models of the heat pads listed above, each will come with a piece of felt like material, cut to fit the top of the pad. This material is the most important part you'll use, because this is the conductor for transferring heat to the seed tray, simple as that. When you set up your heat pad ready to start your cuttings or seed, this felt like material needs to be wet thoroughly and excess water squeezed out. The growing medium used for seeds or cuttings should have been wet and allowed to drain prior to placing on the pad.
Once you get to this stage, you should also have some sort of thermometer to show what the temperature in the tray is doing. Depending on the wattage of the unit, the thermostat should be set to approx. 30C as the initial temperature and then and only then adjust it up or down by using your thermometer. The thermostat can't see what the medium temperature is doing, so be careful here and adjust it to attain an average temperature of 22C.
It's now at this stage where the variables come into using the heat pad efficiently as well as effectively. One variable that will trick you at some point in using the pad, is the amount of water in the felt as when it dries out, the temperature will not stay where the thermostat is set, so water needs to be added to the felt and the temperature will rise to where is was originally set.
Another variable, and there are a few to know, is the moisture in the tray, "what's the mix doing", as with anything where heat is involved the mix will dry out. A higher temperature may give you the indication that the mix is drying.
The most important thing here when watering the felt material, is that if you wet the felt too much, you risk the chance of starting a capillary action, where the excess water will be taken up from the mat and actually soak the growing medium in the tray, damping off will be your friend if you're not careful.
I write this knowing full well that when I grow tomato seeds, I sometimes water with the nozzle on the hose and actually flood the felt. Different people will tell you different things, but whatever you do using the heat pad, is to remember that it's controlled by one person, 'you'. I've been playing with both seed and cutting propagation for a long time and of the two Heat'n'Grow TPS 080 pads I use, one is set to give me 22C at the root level of the growing medium, the second needs to be adjusted when I set up, just like I've described above.
The main thing here is to remember that the water in the felt beneath the seed tray is the conductor for your heat, hone your skills on how wet this felt needs to be and you'll have far less problems using one.
A TPS 040 - 2 Tray in use.
No matter which of these you use, the principal is going to be the same and although it sounds easy to sit a tray of seed raising mix on the pad, you've really got to know a bit about growing with bottom heat in the first place. With all three models of the heat pads listed above, each will come with a piece of felt like material, cut to fit the top of the pad. This material is the most important part you'll use, because this is the conductor for transferring heat to the seed tray, simple as that. When you set up your heat pad ready to start your cuttings or seed, this felt like material needs to be wet thoroughly and excess water squeezed out. The growing medium used for seeds or cuttings should have been wet and allowed to drain prior to placing on the pad.
Once you get to this stage, you should also have some sort of thermometer to show what the temperature in the tray is doing. Depending on the wattage of the unit, the thermostat should be set to approx. 30C as the initial temperature and then and only then adjust it up or down by using your thermometer. The thermostat can't see what the medium temperature is doing, so be careful here and adjust it to attain an average temperature of 22C.
It's now at this stage where the variables come into using the heat pad efficiently as well as effectively. One variable that will trick you at some point in using the pad, is the amount of water in the felt as when it dries out, the temperature will not stay where the thermostat is set, so water needs to be added to the felt and the temperature will rise to where is was originally set.
Another variable, and there are a few to know, is the moisture in the tray, "what's the mix doing", as with anything where heat is involved the mix will dry out. A higher temperature may give you the indication that the mix is drying.
The most important thing here when watering the felt material, is that if you wet the felt too much, you risk the chance of starting a capillary action, where the excess water will be taken up from the mat and actually soak the growing medium in the tray, damping off will be your friend if you're not careful.
I write this knowing full well that when I grow tomato seeds, I sometimes water with the nozzle on the hose and actually flood the felt. Different people will tell you different things, but whatever you do using the heat pad, is to remember that it's controlled by one person, 'you'. I've been playing with both seed and cutting propagation for a long time and of the two Heat'n'Grow TPS 080 pads I use, one is set to give me 22C at the root level of the growing medium, the second needs to be adjusted when I set up, just like I've described above.
The main thing here is to remember that the water in the felt beneath the seed tray is the conductor for your heat, hone your skills on how wet this felt needs to be and you'll have far less problems using one.
The TPS 080 - 4 Tray in use
