I'm no broccoli expert, but my understanding is that young plants should not be allowed to go below 50 degrees F. I wouldn't worry about shocking them. Bring'em in and see if this doesn't resolve the problem. I seriously doubt that change will hurt them.

Can't tell you much about the heating pad. I imagine it should be helpful.

By morning I bet someone who really knows these plants will post a definitive reply. But I'm certain that the change won't shock your plants.

George

I'm sure they need supplemental light. Our "sunshine" up here this time of year is not enough for getting growth out of your starts. Get a couple of inexpensive fluro. shop light fixtures and set up four lights above the plants. Two would probably work but four will be much better. Are you fertilizing the older seedlings? Don't get discouraged, we've all killed lots of seedlings while learning this stuff. Tom

In addition to all of the above this caught my eye..."and thus the water in the trays". If I understand you correctly, do NOT leave water setting in the trays. It causes root rot and thus stunted growth. New roots need oxygen more than they need water so water the seedlings only when the soil has almost dried out.

Otherwise, yes, higher temps and much more light (supplemental lighting is mandatory for healthy seedling) will resolve your problems.

If you haven't already done so, review all the FAQ's offered on the Growing from Seed forum here at GW.

Good luck.

Dave

Also, tell your wife that the growing plants add oxygen to and remove carbon dioxide from the nursery air. :-)

Thanks for the quick responses! Based on what I've learned above, I moved them inside to the nursery, put away the heating pad and drained the excess water out of my drip trays. Oh and I read the FAQs.

I don't expect success with everything, but it is sure fun to see them growing and I hoped some of them would grow.

Skagit Goat Man: Thanks for the heads up about our sun. I had hoped that 8 or so hours of sunlight through a southern facing window would be strong enough to grow seedlings. I do not have a good setup for any sort of grow lights.

Is there any way around grow lights? I will have to do some serious thinking and convincing if I want to put a grow light system inside our house where it's warm. Or I could put it in the garage but it's still cold out there.

Thanks all for the thoughts and suggestions. Any further thoughts?

Here is a link that might be useful: Sinfonian's gardening adventure...

You don't need "grow lights". Most all of us use some simple form of shelving with inexpensive florescent shop lights hanging from them. You'll find many threads about this, many with pictures of their set-ups, on various forums including the Growing Under Lights forum and the Growing from Seed forum.

Even in my greenhouse I have to supply supplemental lights for ideal seedlings. ;)

This FAQ linked below covers the basics.

Dave

Here is a link that might be useful: FAQ on light set-ups

One thing I noticed about brassicas (broccoli and relatives) is that their seedlings can tolerate pretty low temps until about the fifth true leaf stage. Then sharp drops in temp below 50F might cause them to button (flower) when still small. My other bit of experience as a major veggie seed starter: if you are limited in light, keep the air temperature cooler. Usually seeds are more demanding to temperature for germination but growout is less exacting.

Check this out:

Here is a link that might be useful: growing cole crops

If I need to do lights, about the only place I could put them is in my garage. While it is attached to the house, it's not heated, so it gets cold (45 degrees) for most of the day. There is no place in my heated living area that I could build anyting similar to a seedling light system.

I checked out the growing seeds indoors and under lights FAQs and forums but nothing I found told me if warmth was necessary for lighting setups.

Here is a link that might be useful: What I'm doing in my garden

Could you build a mini-greenhouse in the garage large enough to hold your seedlings and a few lights, just a frame covered with heavy duty clear plastic? That would keep the temperature from being so dependent out outside temps, and you could put in a very small heater into the enclosed space.

but nothing I found told me if warmth was necessary for lighting setups.

It isn't that the warmth is required for the lights. The warmth and the lights are both required for the plants. ;) The light amount required is about the same regardless of the type of plants and you can tell from the photos on your website that your seedlings are already quite leggy and badlly in need of light. You can transplant them deeply at this stage and eliminate the leggyness - then get them some lights. ;)

But the amount of warmth required depends, to a degree, on the type of plants. Some, such as tomatoes and peppers, require much more warmth than do cole crops for example.

That said, lighting set-ups will generate some heat of their own - even florescent lights. Some have described a set of shelves encased in clear plastic or mylar sheets to contain the heat from the lights as well as the humidity from the plants, It is like a mini greenhouse.

As anney said if you can provide a light setup in an enclosed area that can be heated to more than 45 degrees in your garage if should work ok. In the 70 degree house would be better - not even a bare corner to set a temp set of wire shelves?? - but adding both lights and heat to the plant area in the garage should work.

Dave

I have my shelves in an unheated pantry. Granted we don't usually have southern temps this low (high 30's, low 40's) in our part of the country, but for the past several months they have been.

As most of my seedlings are started in this unheated pantry, I noticed that the fluorescent lights themselves produce a goodly amount of heat. I raised the temps under those shelves recently to 70 degrees - not because of the seedlings, but because I wanted to heat up some fermenting sauerkraut - which needed that heat to continue to ferment.

Anyway - I also use this approach for my seedlings. I enclosed the area around the seedlings with a cloth to further harness the warmth - and noted the thermometer registered near 70 degrees. Certainly warm enugh for broccolli and cole seedlings.

You might try putting up some shelves, attaching fluorescent lights underneath, and see what the temp reading is. Bet it would work - unless your temps go way down - but another trick yet -

I usually put my sprouted seedlings into yogurt sized cups, about 8 in all, which are then placed in a plastic shoe box (mostly to catch water). These boxes are easily obtained in various variety stores. A 2nd box placed over the top will create a greenhouse effect. I'll bet your little tads will be as cozy as a bug in a rug with this approach - and won't upset things in the OTHER nursery.

Just my 2 c's.

Bejay