Is it much harder to grow cold frame seedlings than under lights?

14 years ago

I don't have room indoors to start plants under lights. Between me and 2 friends, we have a very nice selection of vegetable seeds. All 3 of us are just getting back into our homes since hurricane Katrina destroyed them. We have no sheds or garages to put seedlings under lights.

We can however, put together a really nice cold frame (outside) with our leftover lumber and some poly film.

According to most of the info on the internet, "they" say, in order to prevent frying the seedlings, to open the top of the cold frame on those days when the temperature outdoors gets near 50 degrees. Heck, down here, near New Orleans, it hardly ever gets LOWER than 50 degrees during daytime.

So, if I put tomatoes, peppers, cucumbers, cantaloupes etc in a cold frame with the daytime temps in the 50 to 60 degree range, will they germinate and grow rapidly enough and strong enough?

We were considering using, on our cold frame lid, one of those devices that automatically open and close the vents on greenhouses. We hoped it would open the lid before the temperature rose to the danger point and, close the lid on those occasions when the temps drop. Would it respond quickly enough to avoid damage?

Please share any advice on starting seed in a cold frame since, this will be our first attempt at this.

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Comments (3)

kayhh
14 years ago
Hey Bigoledude. Congrats on getting back into your home. There's no place like it!

I use a cold frame for my plants that have some cold tolerance and need a head start. I start my seedling indoors and move them out as the room under my lights decreases. But in your circumstances you may very well be able to get them going right there in the cold frame. A thermometer that takes and retains readings for 24+ hours can tell you if it is warm enough for germination. (70-75 F)

Or, since seeds do not need direct sunlight to germinate, you could keep them in the warm house until they germinate and pop them out there as soon as they do. In that case you need to provide some dappled shade for them for a few days until you are sure they can tolerate the sun. Plants started indoors need to be hardened.

I just crack open my cold frame before I leave in the morning, more than a crack if I know it is going to get quite warm but I only remove it completely if I am sure it won't rain. A heavy rain can wash away all the delicate seedlings.

There are gadgets you can buy, even fancy cold frame setups, but my view of a cold frame is that it is temporary. Those plants will only be in there for a month. Max. It really is not that much trouble to prop open the top every morning and close it at night. You have to go out there and water them pretty often as well, anyway. Small containers dry quickly in the sun so you will want to check them every day.

Kay (a littleolechick)
stephen_albert
14 years ago
Great to hear you are back home!

I started seed in a "cold frame" in zone 10 (South Florida) for many years. Similar to you, the term "cold frame" did not exactly fit this frame--it was truly a seed starting frame. I replaced the frame's poly lid with a lid of framed chicken wire covered with light horticultural spun poly cloth. Because warming up the inside of the frame was rarely a concern, the cloth lid actually worked to cool the inside temps down. The frame was near the garden and basically served to keep critters out and gave me plenty of room for seed starting. When outside temps did get cool, I popped off the cloth lid and replaced it with the poly lid. Then I monitored outside and inside temps and made sure to prop the lid open when temps warmed--or popped the cloth lid back on.

Here is a link that might be useful: HarvestToTable.com
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Is it much harder to grow cold frame seedlings than under lights?

Comments (3)

kayhh

stephen_albert

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