weird for some reason I didn't get notification this had been replied to. I guess I needed to make myself more clear in the 1st post. I was looking for an on/off type timer not a rheostat simply because that was the method I was using at the time. on for a while then off to keep the temp under control. It was working but was not as well as I liked so in the interim here is what I did: I took the rheostat idea and ran with it. I went to Lowes and got a plug in lamp dimmer. Then I just dialed back the intensity of the lights to 75% (this had my trays all running in the mid-high 80s) so I backed it down to about 50% and now we're sitting in the 75-80 degree range pretty uniformly and I have seedlings galore. so I'm at about $24 ($32 if you count my shop light) but I have 3 seed trays well heated/lit. thanks for the input Shawn

I am not an expert in these things but I tell you what I am doing. The heating Mat is removed or turned-off as soon as I see any sprout. I have home made green house (not a fancy one) In the Basement I several tables and old desks with flourcent lamps hanging from the ceiling. I have over 100 4 Inches plastic pots with good drainage put on plastic plates. I leave, may be one foot between the lamp and the Plants. As soon as the pot sprout I move it from the heating Mat. I read if you leave it on the heating mat it will grow long leggy and thin. As for growing lights I leave 24/7. From my observation Tomato, Cuccuumber, Squash are growing like crazy, Pepper Egg plant are growing but very slow.

Our garden club in Santa Rosa grows 2000 tomatoes from seed every year, and we will start the seed Mar 3rd in cells and then Mar 31 we will pot up to four inch pots. These will all be sold April 15. These are grown in an unheated greenhouse, and may grow a little faster than you can expect if grown differently. Ours are fertilized with time release 14-14-14. Planting in the garden April 15 will sometimes be a little early and a late frost may get them,at least here in the north bay. Al

I think it is working. I was encouraged by the temperature being so even all day. But it must be the lights that are keeping it just warm enough so it doesn't run all day or not very often anyways. Tonight, after the lights shut off at 7, I came down at a quarter to 8 and the readout showed 69.9d f. and the heating light was on and running. So without the lights the temp dropped quickly and heater came on. if that keeps up, I'll be satisfied.