Continued from the previous post, here are a few more things you will need to finish your seed growing mat (very sorry about the delay in posting!!):
- beginning of pad from Part 1
- duct tape
- box cutter or knife
- cardboard boxes
- waterproof cover
- seed growing pods
- potting soil
With your lights settled into the channels, lay down and tape together your deconstructed cardboard boxes. They should reach edge to edge on your mat surface so you don’t get plastic melting onto a light bulb. Then, cover the whole set up with your water proof covering–I had a medical tarp and it works perfectly. Then all that’s left to do is fill your pods with soil and seeds and give it all a gentle spritz with a water bottle. This is where I really have to practice a lot of self-control, but a very helpful post from The Country Basket taught me that the soil just needs to be moist or damp–NOT WET–for the seeds to sprout and take root. Later comes the actual watering, but for now just spritz the soil to keep it damp.
The materials I have used for this project were all free minus the pack of foam. Sure, you could make a really awesome version with all brand-new and longer lasting materials or buy manufactured heating pads, but if you already knew what you were doing, you wouldn’t be here reading my blog would you? Cardboard combusts at around 475 degrees Fahrenheit, Styrofoam is around 375, and standard indoor Christmas lights only reach 240 degrees if you have a ton of them strung together. I only have four strands and since the surface only gets about as warm as the top of my dryer in the middle of a cycle, I’m not too worried about leaving it on overnight. To be safe, I keep all other combustibles away from the unit and I swear on all things beautifully handmade that I will remove this post and warn all posterity in the event that anything catches fire. That being said–happy sowing everyone!!
P.S. Since drafting this post, I had a question on the safety of chemicals being leeched into the air from the Styrofoam heating up. I dug around a bit and although I could not find any substantial evidence on temperatures and toxicity, I do recommend that you keep your growing mat out of living areas. Mine is in front of the basement patio door and the door leading upstairs is always closed during the cold weather.
P.P.S. While using this unit, my seedlings grew in a very reasonable amount of time, all healthy and normal so this is definitely a Tried-and-True project!