During the colder months of winter your seeds need supplemental heat to get started and germinate when growing in an un heated greenhouse. The air itself isn’t as crucial as the soil temperature to get seeds to germinate. Adding a heat source to warm up your soil will speed things along allowing you to start those seeds early, in turn get earlier blooms!! The most common and readily available way of doing that are heat mats. You can get them at your local feed or grow store and even on amazon.
They can range from $15 to $100 dollars . For home gardeners and small scale growers they are a great option but they can add up if you are planning on starting a large amount of seeds at once . Last year was my first year starting a large volume of seeds and was on a tight budget. Once I added up the cost for heat mats to start the amount of seeds I was going to start it started to get costly so to my handy husband I went!! He is an electrical magician and understands how heat is generated from wattage and volts and so on so we came up with an inexpensive way to provide bottom heat to a large amount of area using materials we had laying around!!
We created a simple box made out of MDF ply wood we had scraps of and then lined it with a Styrofoam insulation that we inherited when we bought our farm. This germination mat up above can only fit one 1020 tray on it but the boxes we created you can fit three trays on them.
We then place three strands of dollar store Christmas lights in each box and placed a piece of cement board on the top as the lid. We choose cement board because it conducts and absorbs heat well. I understand all of these things are probably not things everyone has laying around but is still a very inexpensive option for a heat mat rather than purchasing them .
We then plugged the Christmas lights in to an extension cord and plugged in in to a digital thermometer . You can set it to an ideal temperature to keep the soil. It has a little probe you stick in the soil and when it reached that temperature it shuts off.
I added extra protection over my heat mats and created a greenhouse inside a greenhouse so to speak . I used thin wire to form hoops over them and add plastic for those really cold nights but this is me being extra cautious and not a necessity . I have been using our DIY germination heat boxes for going on two years now and they have worked great.
I have seen a lot of other DIY germination heat mats as well . I am not very good at electrical but essentially from my understanding that the wattage is what is producing heat and any kind of light will produce heat. It all comes down to the wattage . Wattage is what produces the heat. We choose to use Christmas lights because they are inexpensive and can easily be distributed to cover a large area and using three strands per box will produce more heat that a germination heat mat. So for an example the heat mat at the beginning of this post is a 20 watt Heat mat. Most 100 count strands of mini Christmas lights produces 40 watts. When you add three of those together that’s 120 watts. Three strands of Christmas lights will produce more heat than a store bought germination mat .If you do the math one germination mat will run you any where from $20 – $40 and three stands of Christmas lights cost $3 from the dollar store or a little more from Walmart but you clearly save a great deal of money when creating your own Germination heat mat.
Well hopefully you learned something today or at least took away a little knowledge about wattage and lighting!! HAHA
Until Next Time,