I bought a heat matt at a nursery for putting under the seed tray. My question is how long do i keep the matt there and on? Is it once the plant comes through the mix? Thanks for the help!!
That's a really good question, but the answer isn't all that simple as there are so many variables. Alot depends on what you are growing, what the indoor temperature is where you are growing your seeds and what the outdoor temps are when you are ready to transplant outdoors.
Tropical plants and some veggies need warmer conditions. I would suggest you do a google search for the particular plants that you want to grow. Try searching with terms such as:
heat mat + pepper seeds
heat mat + tomato seeds
This is an interesting read.
What Newt stated is so true. When I use to grow plants from seeds, I created a three tier propagation house. The top layer provided the highest ambient temp(70F+) and the bottom was the cooler temp(~55 f).
If your seeds are in a 1040 flat, I would wait until the plants are larger than true leaves before you transfer the seedling to a larger tray.
Backyard has a little cheat cheat on germinating seeds on
Seed Germination Database