Start Your Cool Crops In Cold Frames

Get a jump-start on seedlings with this season extender.

If spring temperatures are still a bit on the cool side, but you’re raring to get into your garden, your in luck: Cold frames can be used to get your garden started before optimal planting weather sets in. Cold frames extend the growing season by warming up soil and air temperatures inside so seeds can germinate earlier. If you’re thinking of using cold frames this year, here are some rules you should follow:

1. Nest the frame into the soil.

Except for the hinged door at the top of the cold frame, which can be vented on warmer days, you don’t want cold air to seep into your cold frame—this would defeat the purpose altogether. Dig the edges into the soil so that you have extra insulation.

2. Any materials go.

You can build your cold frame out of new wood, or you can use reclaimed materials to form the frame. You may even consider using material you already have laying around the farm, such as hay bales or cinder blocks, for the sides. However, make sure to use a clear or translucent material for the top. This could be something as simple as a piece of plastic tightly secured onto a frame, or you could use a reclaimed window.

3. Vent the top on warm days.

On cool days, inside the cold frame will be a great temperature for germinating seeds and growing seedlings, but on warm days, it can get downright hot inside if you don’t prop up the lid and let in some fresh air.

4. Grow cool-weather crops.

Cold frames are great for growing things like broccoli, cabbage and kale that benefit from a little spring chill.

By following these simple steps, you’ll be well on your way to getting a jump-start on the growing season.

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