Bottom Heat after germination question

keriann_lakegeneva(5B WI/IL border)February 14, 2010

Okay.. I know it is bad to keep bottom heat going after germination, and I always remove it.... but why?

My bottom heat is an electric blanket so I can turn it way down to maybe 70. I know if I keep it warmer, like germination temps., the little roots will burn and 'run' away from it.

If I keep the blanket on at 70 degrees, is this still a bad idea? I thought the plants may like the extra warmth because it helps keep the air temp 75 at night. Without it on it dips to 62-66.

What do you think? Has anyone else used mild bottom heat throughout the seedling statges?

Keriann~

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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

Seeds need warm soil to germinate but roots need cool soil to grow. :) Seriously, bottom heat on very young seedlings can easily cook the tiny roots..

it also contributes to extra humidity which can lead to damp-off and death and it stimulates excessive top growth that the roots can't yet cope with.

Most all plants, once germinated, much prefer cooler temps for slow sturdy growth. That's one reason why nurseries and greenhouses shoot for a max of 65 degree air temp. So do your plants a favor and turn off the heat blanket.

Dave

    Bookmark   February 14, 2010 at 9:13PM
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keriann_lakegeneva(5B WI/IL border)

Thank you!

I have always been a why why why person...

That makes perfect sense!

Off the topic... but have you ever grown ranunculus?

I respect your advice and appreciate your knowledge. I have only been gardening for 5 years myself.. well because in college it is hard to and I am only 25...

Let me know

Thanks

Keriann~

    Bookmark   February 14, 2010 at 9:31PM
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nckvilledudes(7a NC)

I agree with Dave. I have always heard that the warmer temps can also make the plants put on too much vegetative top growth, whereas the cooler temps allow the plants to put on more root growth faster than the top growth. This results in shorter stockier plants with great root systems ready for planting.

    Bookmark   February 15, 2010 at 8:51AM
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heirloomjunkie(5a)

Keriann,

Nice to see other people my age obsessed with gardening like I am! I'm 24, and I've had a hard time finding anyone in their 20's who even cares about this stuff.

What got you into it??

Kim

    Bookmark   February 15, 2010 at 6:39PM
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keriann_lakegeneva(5B WI/IL border)

I just love being outside and I can only be on my boat so many hours in the summer.. so I made a little garden at my house 5 years ago. I really fell in love with it and it was a great stress relief so I just kept adding them. My goal for next summer is to only have a new wrap around deck, cobblestone walk way and huge beautiful gardens in my front lawn....no grass! I would cover my backyard but I need the lawn for social gatherings and my lovely dogs.

All of my gardens are purple, white and blue only and then I add two to five HUGE containers filled with deep reds... it is really quite a sight.. I am quite proud of myself.

So, what got you into gardening and what are your themes?

Keriann~

    Bookmark   February 15, 2010 at 8:50PM
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sleepy33(5b KS)

I'm 28; an old lady compared to you two! :)

    Bookmark   February 16, 2010 at 12:13AM
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sarahbarah27(5)

I'm 26! Judging from this post, there is quite a few people in their 20's...I never would have guessed!

    Bookmark   February 16, 2010 at 6:31AM
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keriann_lakegeneva(5B WI/IL border)

Either would I.

Woo Hoo! that is nice to know there are other 'crazy' young people. Some of my friends think I am nuts about gardening but come Spring I am always helping them out and giving away plants!

Keriann~

    Bookmark   February 16, 2010 at 6:44AM
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heirloomjunkie(5a)

Yay! So good to know I'm not the only one. My grandfather grew up on a farm, and I've always loved plants and animals. Last year, I thought I would try it just to see if I liked it. Now I'm hooked. I like coming home from the office (beige land) and digging in the dirt and sitting in the sun. Such a relief.

Keriann- you're garden sounds amazing. I'm attempting flowers for the first time this year - sunflowers. I usually just do vegetables. Starting my onions today! Something so neat about knowing where your food comes from.

Kim

    Bookmark   February 16, 2010 at 11:04AM
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tn_veggie_gardner(7)

Dave: What do you think about using heat mats in a cold frame (haha) that is being set up specifically so plants can go outdoors a few weeks before last frost date? Would the heat mats still be too much for the plants (which, at that time, will be around 2 to 2 & 1/2 months old)? I will have them attached to a thermostat, which I believe has little prong things that you place in the soil to take the temperature from.

- Steve

    Bookmark   February 16, 2010 at 12:40PM
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four(9B (near 9a))

> Posted by nckvilledudes
> I have always heard that the warmer temps can also
> make the plants put on too much vegetative top growth

Was the context always SOIL temp?

    Bookmark   December 21, 2013 at 1:06PM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

The focus is soil temps for germination. Air/ambient temps for growing on after germination.

Dave

    Bookmark   December 21, 2013 at 1:12PM
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seysonn(8a WA/HZ 1)

Steve,

Heat mat is meant just for germinating seed, not for providing heat for faster growth. You can use a 100w incandescent light to keep your cold frame warm at nights.
In cold frame, early spring(right around the last frost date), in a sunny day will be warm enough both to germinate and grow.
YMMV
I usually start a lot of cool crops in my cold frame as early as a month before LF date. Sometimes it can get too hot and have to vent it.

    Bookmark   December 21, 2013 at 2:07PM
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four(9B (near 9a))

> Posted by digdirt
> The focus is soil temps for germination. Air/ambient temps for growing on after germination.

So, you take nckvilledudes statement as refering to ambient.
Then, do you agree with it, that cooler ambient favors root growth?

    Bookmark   December 21, 2013 at 5:10PM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

Four - you may not have noticed but this is a 3 year old thread. I'm not speaking for nickvilledude but if you read it from the beginning you'll find that yes, I said the very same thing in my first post.

Once germination happens then cooler ambient temps slows top growth and favors root development. That's pretty standardized knowledge.

But then perhaps I'm not understanding exactly what your question is?

Dave

    Bookmark   December 22, 2013 at 6:39AM
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hairmetal4ever(Z7 MD)

I know this to be true, but is it true even for plants like tomatoes and peppers that languish in cool night temps?

BTW I'm 36 and have been gardening since I was 10. Wasn't as good of a way to pick up girls when I was younger as I thought it would be...haha.

    Bookmark   December 24, 2013 at 9:29AM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

but is it true even for plants like tomatoes and peppers that languish in cool night temps?

Again the important distinction is between AIR temps and SOIL temps. Tomato plants don't languish in cool night temps IF they are growing in warm soil - one reason why using black landscape fabric mulch on the soil for example can allow for much earlier transplanting.

We all try to force top growth as it is the most visible sign of plant development. But we have to remind ourselves now and then that the focus early in a plant's life isn't top growth. It is root development. Bodacious top growth without the root development needed to support it only leads to stressed plants with all sorts of problems and poor production down the line.

So while a plant may appear to be languishing at times - in that there is minimal top growth to be seen - that doesn't mean it isn't thriving at the root level.

Dave

    Bookmark   December 27, 2013 at 7:45PM
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