Heat mat after germination...?

Turn it off unless the area would get below 50 degrees at night. And in that case, you might want to move the mat out from under them and run it to warm the air. (Otherwise you might have to water the plantsquite often.) The optimal temperature for sprouting seeds is higher than the optimal temperature for growing on good, sturdy plants.

I myself wish I could *lower* the temperature where I raise my plants.

Thanks for your comments...

Can you tell me anything at all about what specific effects one might expect from leaving the heat mats on as the plants grow?

Thanks again,

Kenneth,

Depends on the plants. Anything that normally requires warm temperatures to grow will do much better if you leave the heat on. For example, I keep tomato and cactus seedlings on the heating pad until it is time to harden off in preparation to moving outdoors. As noted by another reply, plants that require cooler temps should be taken off the heating pad after germination. For example cabbage and primula.

--beeky

Kenneth wrote:

Hi Beeky,

Thanks so much for your response...

I am having a problem with tomato seedlings becoming super tall (leggy?) and wondered if that might relate to the heat issue.

They are still at the two-leaf stage but some are so tall and spindly that they cannot support themselves.

Thanks for any further thoughts,

The symptoms are either from too much heat or nitrogen, causing them to grow too fast, or not enough light------are they bending toward a light source. I remove bottom heat as soon as about 50% of my seeds have germinated. Bill

nks for your comments...

Plants that grow too tall too fast, even though they have adequate light. Pots that dry out too quickly.

Also, a drop in temperature at night is natural and desirable -- within limits. For tomato plants, the nightly low should be higher than 50 degrees F.

Hi Pat,

I thank you for that comment... The drying is no big deal for me, but the rapid growth that I have seen may be attributable to the heat mat. I will turn it off after germination.

All the best,