Get a Hot Start on Cool Season Veggies

a picture of young seedlings in a tray

Can’t wait to get out in the garden?  You can start sooner and have easily grown produce if you plant cool season vegetables! 

By Mara Higdon

(This article was first published in The Gateway Gardener Jan./Feb. 2011 issue)

Can’t wait to get out in the garden?  You can start sooner and have easily grown produce if you plant cool season vegetables!  Cool season veggies such as spinach, mustard, radishes, cabbage, kale, swiss chard, broccoli, and an array of lettuces can be started as seedlings indoors in February or sown in ground in a pre-warmed area of your garden.  These veggies thrive in the cooler weather of our early Missouri springs.  Many of the cool season veggies are also high in vitamin A and/or C.  A double bonus!

Start your seedlings indoors using the chart below as a guide. Some optimistic gardeners plant early with the hopes of mild winter weather. A week or two before the transplants are ready, prepare the garden space. To do this you will need to build a cold frame that consists of a temporary wall and an old window in the area you want to grow your veggies.  You can build your wall out of hay bales, concrete blocks, or even old bricks.  Then place the window on top of it horizontally.  This structure will allow the soil below to be warmed when the sun is out during the day.  It will also provide a bit of wind protection for your seedlings as they being their new life in the ground.  Once the weather looks promising you can try planting your seedlings outdoors.  Take note! If the temperatures take a turn for the worse (and they definitely can at that time of year), you may need to cover them if there is a threat of a cold spell for more than 2-3 days.

Make sure that that you check on the seedlings daily.  Water your seedlings as necessary, but try to do it during the warmest time of the day.  You may also need to ventilate your structure on sunny windless days by propping it open a few inches.  It can get quite warm in the cold frame at times. If you’re an experimental gardener type, you can also direct sow one row of a particular cool veggie every week or so to extend the harvest time.

Below is a list of cool season crops you can try with the indoor and outdoor start dates for the Central Missouri zone.  I have categorized them according to the vitamins they provide your body.  Happy gardening!

Mara Higdon is the Program Director at Gateway Greening. They focus on community development throughout the St Louis area.

Vitamin A (I.U./100g) Dates to Start Seeds for Transplants Dates to Start Outdoors/ Direct Sow
Carrot (12,500) NA 3/15 – 4/5
Leaf Lettuce (1620) 3/1- 4/1 3/15 – 5/10
Swiss Chard (9690) 3/15-4/1 4/1-5/30
Vitamin C (I.U./100g) Dates to Start Seeds for Transplants Dates to Start Outdoors/ Direct Sow
Cabbage (31) 2/15-2/28 3/20- 4/20
Cauliflower (28) 2/15-2/28 3/20- 4/20
Kohlrabi (37) NA 3/25-4/15
Vitamin A & C(I.U./100g) Dates to Start Seeds for Transplants Dates to Start Outdoors/ Direct Sow
Broccoli (3400, 74) 2/15-2/28 3/20-4/10
Collards (7630, 44) 2/15-2/28 3/15-4/10
Kale (8380, 51) 2/15-2/28 3/20-4/5
Mustard Greens (7180, 45) 2/15-2/28 3/15-5/1
Spinach (11790, 30) 2/15-2/28 3/20-4/20
Turnip Greens (10600, 60) NA 3/20-5/1