i recently tried using jiffy seed pellets (72 per tray) to germinate flower seeds. i am using lights and heat mat. the seeds have started to germinate quite well. how long do i leave them under the lights after the first true leaves develope? since it is about 4weeks before I can plant out, i am afraid that the pellets will be too small and will restrict the root growth. should I repot into peat pots ? if so what size
I don't like peat pots bc in the past when I pull up annuals In the fall there are little hard slabs where the peat should have disappeared and the rootball is tiny. If I'm stuck with them I pull them off as much as possible before I plant, even if it means tearing some of the roots.
This year I also got good germination (tomatoes) with Jiffy pellets, but the roots grew out the bottom very quickly and I had to pot up before the true leaves came out.
I repotted to 7oz Dixie cups bc I couldn't find the right sizes in NYC. Since then I've ordered 2 1/2" pots online from Greenhouse Megastore and will use them from now on. They are perfect.
Can't wait for spring so we can open the house-- wont be long now!
Jim, to answer your other question about lights, they need to be under the lights continuously until you move them out. Even bright southern facing windows don't provide enough light or a long enough duration of light for them to develop normally. I keep my florescent lights on for 14-16 hours a day. The longer light period helps make up for the lower intensity. Also, if you haven't already, turn off the heat mat once you have germination. Low light coupled with warmer temperatures will result in leggy plants. Cooler temps will slow down growth slightly and result in much sturdier/healthier plant to transplant outside.
Jim, I use pellets successfully every year. I've learned that when the roots start to stick out, it doesn't hurt anything, and that roots will continue to form inside the pellet for quite some time. I usually pot up just one time on things like tomatoes and petunias (because I start them extra early.) The rest do just fine as long as I keep them moist.