Hi the problem with a coldframe is that you won't have enough heat your seedlings will get nipped by frost. Otherwise you just use seed starting mix in containers and plant away.

I built a new 5x8 coldframe and it has worked great this year. Doesn't get too cold here though, lows around 25. I built it b/c I'm soooo tired of dragging my seedling trays and pots in and out every day. What a pain!

Anyway, I start my seedlings inside (about 1 week), then move to the coldframe during the days for sunlight but bring back in at night (about 10 - 14 days), and then leave them in the coldframe all the time once the plants have some leaves and look strong. I still have to lug the trays around some, but not nearly as much as last year.

As a side note, it got down closer to 20 here one night here and I lost a few plans (about 8). Not too bad considering I probably have 100 in there. I started throwing an old comforter over it at night. Don't know if it really helps but I haven't lost any more plants and it makes me feel better.

I always start mine in a coldframe. I plant them in 2 litre bottles cut in half (about) making drainage holes in them. I then split the sides of the top, so it will fit down over the bottom and leave the cap off. I place the coldframe in a sunny location but then must be careful to crack the window lid on really warm sunny days, or even cover the frame on exceptionally cold night nights.

My last expected frost date here is May 10th, so I usually start them around the first of April.

Last year I used the bottom of a plastic doghouse, blocking the door opening with a piece of wood, and just laid the window on top. Definitely not the prettiest coldframe, but it sure helped to feed my tomato obsession by being able to start lots of varieties.

Sue

I do like Brainray and germinate indoors. I put them on top of the fridge for bottom warmth. Once they sprout I put them in the bathroom garden window for a day or two, then move the seedlings into the cold frame. If the predicted overnight low is in the 30s I'll toss an old flannel sheet over the coldframe. If it's much lower, I'll bring the plants indoors for the night, but that's rarely needed.

That's the kind of information I am looking for. My last expected frost date is 4/14, so I figure if I start around March 7th I'll be in good shape.

Does the fridge really throw that much heat (I put a compost thermometer on top of the fridge for about 4 hours and it registered the same temp as the themostat setting in my house - 70 degrees)?

Secondly, how much do milk jugs in the cold frame help to maintain a bit more consistent air temp in the cold frame?

I plan on building a cold frame this spring, late March. I have all the materials on hand, old (30-40 yrs) 2 x 4's, and stiff plastic for the window. The 6'x12' garden plot has a fence and is full of leaves from last fall. I'll clear a 4'x 8' space and mound up the leave around the sides of the frame for some added insulation. Earlyon I plan to bring out warm water-filled 1 and 2 liter bottles before sundown to place in the frame for added warmth during the night, then late April leave them in the frame on sunny days to warm up. I have black cloth to put on the leaves around the frame to further add warmth to the area (I hope this will also speed up the leaf composting.) I have to figure out a cover for the frame for cold nights. I have extra house insulation and may devise a blanket of insulation in garbage bags glued together, hopefully well enough so that moisture cannot get in. I'll put six of the tomato plants in place permanently so that when I take the frame apart (or not) in the spring they will already be in place. The rest of the space will be for tomato transplants, lettuce, etc.I'll put a thermomoter in there first to see what the night time temps are before I put the seedlings in.

Everyone need a hobby :-)

Eaglesgarden, I am in zone 7a or 7b, depending on where you look, in NC and our last average frost date is April 15th. Are you sure about your last expected frost date? Kind of hard for me to fathom our last average frost dates being the same in NC and PA.

I used to use the top of the fridge before I got a heated seed starting mat and it worked great for tomatoes.

I am in the SE corner of PA (just south of Philly), I think the proximity to the ocean helps to get the temps higher faster. (According to almanac.com I could be planting out Tomato plants by April 7 - I'll probably end up somewhere around 4/21) It seemed a little early to me too, but I was able to start tomato and pepper transplants and corn from seed around 4/21 last year.

I will have some red plastic in place in my planting area to warm the soil a little faster, and I have a bunch of milk jugs to use as cloches, in case of a few cold nights. (My wife doesn't understand why I've been saving milk jugs for the last 3 months, but she doesn't mind (as long as they are neatly stacked in the laundry room!).

Here's what I do: plant seeds in small containers (such as the ones plastic-wrapped mushrooms or blueberries come in; they're usually blue or clear), close together; put these on a box I built with a heating cable in sand under a sheet of screen, and germinate them at a relatively high temperature (around 80° to 85°). When they've developed true leaves, I prick them out into small square pots or flats and grow them under close fluorescent lights, cooler with a tiny fan blowing over them. At a certain point I move them out to my cold frame that also has a heating cable, for nights where the temps go too low (below 45° or so. The cold frame has a rounded top (heavy clear plastic over PVC frame, also homemade). They do well in this set-up, which is also used to harden them off before planting in the gardenÂof course here in central MN that's usually not before Memorial Day. GaryStPaul

Some additions to comments upthread:

I have a coldframe in Denver area. Works all winter long. Cautions:

o Venting heat is an issue. If you are at work on a sunny day and cannot vent excess heat, you may come home to dead plants.

o I retain heat at night by either 1 gal mik jugs or those flat 2.5-gal drinking water containers (the $2.49 kind) with the spigot on them with water dyed dark blue to collect more heat. When I uncover cold frame on cold morning, jugs still giving off heat.

o As above, your soil temps could be inadequate for germination inside a cold frame. Start inside, set outside for best chance.

Dan

Thanks Dan....good stuff.

How does this sound?

I plan on starting them indoors in the next week or so, - I have a nice south facing bay window in my bedroom that is currently getting about 6 hours of full sun right now (should be closer to 6.5 in the next week (based on the angle of sun and extended daylight - approx 2 min per day) then placing them out in the cold frame about 2 weeks after germination - or 2nd set of true leaves, whichever comes first.

I am going to pot them up to 20 oz. plastic cups when first leaves arrive and leave them in that size until planting out time (approximately 7 weeks from germination - 4/21-28).

The cold frame is approximately 8 feet long, and 3 feet wide, 12 inches in front 24 inches in back. I plan on having 30 tomato plants in that space along with about 20 1 gallon milk jugs filled with water (dyed dark, thanks to Dan!). Is that enough thermal mass to keep the heat up at night, even if temps go into the mid-30's? I have an old area rug cut into pieces to go over the top for extremely cold nights, as well.

I just grow mine in a cold frame and take the top off a month later
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stquack,

When do you start them? How much does the black plastic help you?

Thanks...great pics!

Eaglesgarden--Our average plant date for tomatoes is mid-may. I start mine in my garage around the first week in February. With the cold frame I plant mine out around mid-April. The black mat is dupont weed mat. It works great by make heat and keep the weeds out.

Hi,
I started my tomatoes the last week in January and they are doing great!Just getting quite tall! I have two cold frames filled with manure,straw,and dirt. We live in Ohio. I'm not sure when I can start putting them out there? I would appreciate some answers! Thanks