Cool Season Vegetable Bulbs

Asparagus crowns

Asparagus grows best in deep, well-drained sandy loam soil.  Improve Colorado soils with organic matter like compost to increase drainage.  Make a trench 8“deep, in rows 4’ apart.  The asparagus crowns are then laid in the trench 8-12” apart.  Cover the crowns with 2-3” of soil.  Once the asparagus begins to emerge in the furrow, gradually fill in and cover small weeds.  Eventually the furrow should be level with the surrounding soil.  Some spears may be harvested the first year on a limited basis.  Each year your harvest will increase.  Full harvest will be reached in 4-6 years.  You can leave the ferns for winter interest and cover for wildlife.  Mow the ferns the next year.  Choose from Mary Washington or Jersey King varieties.

Garlic bulbs

Garlic performs best when planted in a light, sandy soil that has been amended with compost.  Long days and warm nights help in bulb development.  Plant in early spring when the ground has warmed to 50 degrees.  Dig a hole 3-4” deep.  Break bulbs up into individual cloves, set firmly in place with pointed ends up.  Replace the soil covering the bulbs.  Water well after covering.  Allow soil to dry between watering.  Harvest mid-late summer.  Choose from California or Silver Rose varieties.

Onion bulbs

Plant in a well-drained soil that has been loosened.  Control weeds around sets with frequent shallow cultivation.  Plant apart in rows and only deep enough so that the tops of the bulb sets are covered with soil.  Harvest at end of season when fully mature and air dry.  Choose from red, white or yellow varieties.

Potato tubers

Plant potatoes in a sunny location in early spring.  Soil should be worked 12” deep before potatoes are planted and fertilizer mixed into the soil.  Always be sure the tubers are covered with 1” of soil.  Cut the seed tubers into pieces that each contain 2-3 eyes, from which the new shoots will emerge.  Allow the cut pieces to heal over-night to help prevent disease.  It is important to water regularly and not over-water.  As a general guideline, potatoes should be watered weekly during warm summer weather.  Harvest early to mid-season.  Choose from Red, Russett or Yukon Gold varieties.


Plant in early spring in a sunny location with well-drained soil.  Spacing is important to have a successful crop.  Plants will not develop and are more prone to disease if planted too close together.  Prepare the soil incorporating a good garden fertilizer.  Plant the crowns 3-4” below the surface with the crown bud about 2” below the soil.  Space the crowns 1.5-2’ apart.  Do not harvest the first year.  This will allow the plant to send it’s energy and nutrients back to the roots to ensure a strong root system.  Do not remove more than one half of the stalks when harvesting, leaving stems to generate new growth.  Choose Canada Red variety.