Getting an early start with cold weather crops

This spring we decided to do a little experiment: Determine the frost tolerance of cold weather crops, such as cabbage, lettuce, radishes, spinach, and broccoli.  In our neck of the woods, central South Dakota, the average last frost date is around May 20.  We reasoned that we could get two crops out of each bed instead of one if we planted both spring and fall crops.  Most gardeners around here just plant their cabbage, lettuce, and other cold hardy crops along with their beans, peppers, and tomatoes.  We felt that we could improve on that system with a little learning.  And I must admit, a strong part of the reason for doing this was so we could get down to the business of growing plants a lot earlier.

We started our cabbage plants under our growlight setup, which I will write about in a later post, on - get this - February 15!  On February 19 we had sprouts, and a day later we started our broccoli.  We started our Napa (Chinese) cabbage on March 2, thinking it wouldn't be quite as hardy as the cabbage and broccoli.  It turned out to be a correct assumption.  Over the next two weeks, we also started Paris Island Romaine lettuce, Brussel Sprouts, leeks, and several herbs.

After hardening off, we planted our cabbages and broccoli in one of our chicken manure fertilized beds in the last week of April.  We experimented with milk jugs and plastic covers to deter frost.  The milk jugs didn't work well.  We had issues with aphids, and the plants with milk jugs were always worse.  The plastic was way better.  We watched the weather fairly closely and covered when it fell below about 27 degrees.  The plants endured mild frosts without flinching, and once they were established and healthy and the aphid population was knocked down by our garlic/soap spray, they endured frosts as cold as 23 degrees. We had a very mild spring,  however, and I am anxious to try this in a more normal (what's normal?!?!?!) year, when frosts will be more severe and blizzards are a possibility.

We had great success with early planting this year, with bountiful crops of Romaine lettuce, spinach, radishes, cabbage, and full broccoli heads before anyone else's plants were even thinking about heading out.  I encourage anyone to grow their cold season crops when its cold.  They grow way better, and don't mind a bit of frost.