Spring Planting for Summer Harvest: How to Choose and Plant the Right Cole Crops for Outdoor Gardening in Denver

The birds are singing, the grass is becoming greener, and we no longer meet the weather forecasts with groans. What does that mean? Spring is finally upon us!

spring has sprung chalkboard display

Gardeners, don your gloves and grab your trowels! If you’re looking to grow cole crops, now is the time to start planting for a bountiful summer harvest.

“Cole” indicates that a plant belongs to the cruciferae, or mustard, family. There are two categories of crops: those that can be planted in cool growing temperatures (between 60 degrees and 80 degrees Fahrenheit), and those that can be planted during warm temperatures (70 degrees and 90 degrees Fahrenheit).

Cole crops prefer to grow in cooler temperatures, which makes them a good choice for early spring planting. When you’re planting cole plants in the spring, you’ll be able to harvest them early- to mid-summer. Viable cole-crop options include broccoli, cabbage, brussels sprouts, cauliflower, kale, carrots, lettuce, peas and kohlrabi.

ornamental kale and pansies

Cole crops have specific flavors that are dependent on their outdoor living environment. For instance, if the temperature becomes too hot, the amount of sugars produced by the crops is reduced, making them less sweet.

Keep in mind the following guidelines:

  • Cole crops should be planted in soil that’s rich in organic matter and nitrogen, as well as moist and well-drained.
  • It’s helpful to use a plant starter fertilizer when planting cole crops, as they require a lot of nitrogen, phosphorus, and potassium to grow. With the help of such brands as MiracleGro, Peters, or Rapid Grow, your crops can yield 20 percent more than going without fertilization.
  • To ward off weeds and maintain moisture levels, use mulch.
  • Make sure your cole crops don’t dry out by using proper irrigation and mulch.

If you’ve already started your cole crops and have germinated them indoors, you’re ahead of the game. It’s ideal to grow these seedlings in temperatures from 60 to 70 degrees Fahrenheit, and spring affords them the perfect temperature conditions for planting. Just make sure you get them into the ground when they’ve only matured for about four weeks. If they are older or even taller than four inches, they can become too weak and break easily during transplanting.

Lettuce closeup 2

If you’ve purchased cole crops that have already been started in a little cup, it’s important to handle the transplantation process very delicately, so as not to damage the plants’ root system or stem:

  1. Remove the plastic cup by turning the plant upside down and gently prodding it until it loosens. Make sure to NOT pull it, as this is the easiest way to damage the stem or separate it from its roots.
  2. Gently remove the lower leaves on the plant so that it can be placed more deeply into the ground than the soil already surrounding its roots would indicate.
  3. Make a hole in the ground deep enough for the plant’s stem to be half buried. Insert the crop and surround it with soil.
  4. Place mulch around the base of your crop.

If you’re worried at all about pests, consider using the biological control product Bt, which has proven to be useful for cabbageworm and looper, both pests that have plagued Colorado crops for years. Bt stands for Bacillus thuringiensis and is a naturally occurring bacteria that acts as an insecticide. Even if your garden is all organic, Bt is considered safe. Just note that if you’re going to use it, Bt is destroyed by sunlight, so you’ll want to apply it thoroughly at night.

If you’re looking for tips on planting cole or any other crops this season, come down to City Floral Garden Center. We have a huge selection of plants ready for your Colorado garden, as well as all the tools you need for gardening success.

Comments are closed.