heat mats

[buckhunter]

when starting plants in the basement under grow lights should I remove the heat mats after the seeds have sprouted ?................... Or leave the heat on while the plants grow until time to transplant to the garden .

[recruiterg]

I take the heat mat out once germination has taken place.

[JamesL]

Agreed. Definitely take the mat off. Just keep the lights real close.

[Redbaron]

The trick when sprouting multiple varieties that have different germination rates is to time it right. Don't wait till everything has finished sprouting. Take them off the heat mat when the majority has sprouted or has started sprouting.

BUT There are times being on a heat mat actually helps even AFTER the plants have sprouted. If you are using natural light and natural heat, and the greenhouse or low tunnel or cold frame, whatever, would get too cold because of the weather, yet there is plenty of sunshine, then plug that heat mat in! At least at night.

Just use your judgement. With experience, that judgement will get better and better.

[bughunter99]

My heat mat is smaller than my tray so I tend to move my plants around alot. Sprouted plants get immediately moved to the cooler zone.

[roadrunner]

Good advise here - remove or shut off mat once seedlings emerge. The only exceptions I've made with good results were with some of my hot peppers. They seem to thrive on the warmer soil until they have their first set than I usually give them the "cold treatment" for a few weeks.

[RebelRidin]

Originally Posted by roadrunner

Good advise here - remove or shut off mat once seedlings emerge. The only exceptions I've made with good results were with some of my hot peppers. They seem to thrive on the warmer soil until they have their first set than I usually give them the "cold treatment" for a few weeks.

Completely agree.. both about the toms and the peppers.

[enchant]

Sorry for necroing this old post, but I'm just starting now.

Last year, I grew a few plants from seeds, but this is the first year I'm really taking it seriously. I bought a 98-cell tray with it's own clear enclosure and a heat pad to go under it. I planted four days ago, and the results so far have been far better than I expected. The slicing and pickling cukes are four inches tall after only four days!. I've had to repot them already.

I've got a wide assortment in the rest of the cells. Twelve varieties of tomatoes, a few herbs, a few peppers, etc. Aside from the cukes, about a third have sprouted and some are an inch tall. But the rest are showing no action whatsoever. So I guess I'm concerned about what to do. Will the heat harm the sprouts? It's still very cold here in the Boston area. Snow today and below freezing. At night, the temperature in the house gets down to about 60. Inside the seedling container with the heat pad and under the grow light, it's typically 75-82.

I wish I could split out the seedlings from the under-achievers, but that isn't possible without hacking my tray, which I'd prefer not to do. Which is the lesser of the two evils?

[kath]

Originally Posted by enchant

Sorry for necroing this old post, but I'm just starting now.

Last year, I grew a few plants from seeds, but this is the first year I'm really taking it seriously. I bought a 98-cell tray with it's own clear enclosure and a heat pad to go under it. I planted four days ago, and the results so far have been far better than I expected. The slicing and pickling cukes are four inches tall after only four days!. I've had to repot them already.

I've got a wide assortment in the rest of the cells. Twelve varieties of tomatoes, a few herbs, a few peppers, etc. Aside from the cukes, about a third have sprouted and some are an inch tall. But the rest are showing no action whatsoever. So I guess I'm concerned about what to do. Will the heat harm the sprouts? It's still very cold here in the Boston area. Snow today and below freezing. At night, the temperature in the house gets down to about 60. Inside the seedling container with the heat pad and under the grow light, it's typically 75-82.

I wish I could split out the seedlings from the under-achievers, but that isn't possible without hacking my tray, which I'd prefer not to do. Which is the lesser of the two evils?

Keep checking to make sure the medium in the cells is damp but not too wet and that the temp stays in the range you mentioned during the day and night. Some types of seeds (like brassicas and cukes) will sprout in a couple of days and others will take longer. You should be seeing tomatoes within a week, but peppers take a bit longer. Herbs will vary, too, with parsley taking a couple weeks.

Planting everything in the same tray will be a real pain- figuring out a way to get the things that sprout into strong light and out from under the humidity dome as soon as they emerge is critical and they also won't be happy if you keep them on the heat mat for very long, ie. they'll get tall and thin.

Sorry to be the bearer of bad news...

kath

[enchant]

Not bad news - helpful news. So perhaps these 1" seedlings should be replanted?

[kath]

Originally Posted by enchant

Not bad news - helpful news. So perhaps these 1" seedlings should be replanted?

What kind of seedlings?

[enchant]

Originally Posted by kath

What kind of seedlings?

Well, the early sprouters are mostly cherry/grape tomatoes, about 1/3 of the san marzano and brandywines, and some basil.

[kath]

Originally Posted by enchant

Well, the early sprouters are mostly cherry/grape tomatoes, about 1/3 of the san marzano and brandywines, and some basil.

Tomatoes can stay in 72-size-cells until they have at least one set of true leaves. That's the size I'm familiar with and I usually pot up between 2-3 weeks when the root ball is established. Not sure about basil. Again, just make sure they're getting the light they need.

[nnjjohn]

Originally Posted by kath

Tomatoes can stay in 72-size-cells until they have at least one set of true leaves. That's the size I'm familiar with and I usually pot up between 2-3 weeks when the root ball is established. Not sure about basil. Again, just make sure they're getting the light they need.

Most my plants in two 72 cell trays are doing just fine after three weeks.. I only used the heating pad and led grow lamps for the first ten to twelve days with the dome until most of the seeds germinated.. now all they get is window sun and three times a day mist spray bottle watering.. I won't seed any cucs or zucs yet,, they grow too fast this early..i will seed for a total dozen at best of cucs yellow and green squash for my family garden. The tomato plants can stay in those individual 72 cells until they have at least three or four true leaves .. I transplant the healthiest looking ones in three inch dollar store cups using the same seedling mix basically mg seedling mix which is fortified peat. I lift out using a small baby spoon between the cells leaving the rest in the cell tray with more space between them in the cell tray. I'll do this in about another week and have at least four times what i'll be using in my garden beds. The rest I'll give away after i know all my transplants are doing good after a week in the ground.

[JamesL]

Enchant,
Kath is right on all counts. You could go ahead and repot the Toms if you are careful. You could also let them ride awhile longer. Easy to cure leggy toms later by potting them deep.
The cukes - I hope you have larger pots and extra space. I usually wait an extra 10 to 14 days to start them as they get out of control quick indoors.