Friday, July 23, 2021

Homegrown Arugula in January!

By Lindsay Graves, Eagle County CSU Extension Master Gardener

Homegrown arugula in January? At 6,700’?  Yep! With some low tech season extension techniques, the hardiest salad greens will overwinter in much of Colorado, so you can enjoy tasty treats in winter and early spring harvests before many gardeners can even plant!

Once you become accustomed to the taste and heft of homegrown leaves, you won't want to go back to store bought.

Let’s consider the challenges:

  • Space

    • Harvested in fall but planted in summer. Our space is typically filled with summer veggies. Where will the greens go?

  • Cold

    • Certain vegetables have adaptations to help them survive.  Some concentrate sugars in their tissues to lower freezing point; some have extra space between their cells so ice crystals don’t cause as much damage.

  • Light

    • Between Nov 15 and Feb 1, days are too short for much growth, so the plants are in basically a waiting state.  When growing fall greens, we have two options: grow them to near full size and hold for fall + early winter harvest, or grow them to a small size and overwinter and resume growth in the spring for late winter + early spring harvest.  

  • Water

    • When the ground is frozen, plants can't drink water. Our dry winds pull moisture out of their tissues.  

While formidable, the challenges can be overcome.  Let’s check out the solutions.

  • Planning

    • Incorporate a patch of cold season greens in your planting plan. They can follow the first planting of greens, peas, or garlic. You'll want to plant in mid July for fall harvest and early Sept for spring harvest (in my garden at 6,700’).

  • Starts vs Seeds

    • Using starts is a great idea! Planting a 4-6 week old plant vs a seed saves you time and space. It can be hard to source seedlings in summer, so start your own. Seeds will work too though if you don't want to grow starts.

  • Season Extension

    • Row covers provide a more even temperature and allow plants to start growing earlier in the morning and later into the evening, so they can size up quickly. Add a row cover after day time highs drop below 85. Add plastic over the row cover when heavy snow threatens (so it doesn't rip the row cover). Plastic must be vented daily until the highs are below 60.

  • Suggested Varieties

    • Lettuce- winter density

    • Mache-any

    • Tatsoi-any

    • Arugula-Speedy

    • Spinach-Space for fall harvest

    • Winter Bloomsdale for spring harvest

The Fall Greens Gardener’s Year-round Checklist


  • Add cold season greens to your planting plan

  • Order cold tolerant varieties with your seed order


  • Clean your seed starting kits thoroughly after their first round of use

  • Replenish any seeds starting supplies that were used up


  • Harvest something to make space for greens

  • Apply a rich compost (like worm castings)

  • Sow greens (in ground or in starting kits). Make last sowings by Sept 15.

  • Cover (row cover after day highs below 85, plastic after day highs are below 60)


  • Harvest greens on warm days when leaves are not frozen. They will resume growth after Feb 1.

My cabbage in October

My lettuce in October

Friday, July 9, 2021

Keeping Your Aspen Trees Healthy

By Eric McPhail, Gunnison County CSU Extension

Everyone enjoys watching the aspen leaves as they glitter in the wind and change colors. But aspens do have enemies. Two of the most common are cankers and Eriophyid mites.  


The term canker describes an area of dead cambium (living cells just beneath the bark) and bark, usually on the tree trunk and usually elliptical in shape. Aspen cankers display great variety.  They can kill individual twigs, branches, and portions of trucks when it succeeds in girdling those parts. They kill many aspen each year in Colorado, and affect all sizes and ages of trees.

Cytospora is probably the most common canker-causing fungus. Look for orange-stained areas of bleeding bark, small orange tendrils of a jellylike material on the bark, and large patches of dead bark. Sooty-bark cankers give the trunk a “barber pole” appearance. On close inspection, the stripes or areas of dead, black bark crumble in one’s hand to a sooty powder. Black cankers are large, black swollen or flared areas on the trunk that contain concentric rings. This feature gives them the nickname of “target cankers.” 

Black canker

Canker fungi travel from tree to tree in interesting ways—some have their spores disseminated by wind, others by rain, still others by insects—and humans do a good job as by well by not cleaning their pruning shears between cuts!

Prevention is much more profitable than attempts at control. Avoid wounding the aspens by carving on them which means almost certain death to the tree! Sufficient watering also keeps the trees from being under stress, which makes it more susceptible to insects and disease.

If a small canker is found on a branch, prune it off. Although pruning is preferred during the dormant season, if you must prune during the growing season, be sure to sterilize the pruning shears by soaking them in a 10% Clorox® solution, by spraying the blades with Lysol® disinfectant, or by using some other alcohol product after each cut

Small trunk cankers can sometimes be cleaned up by removing affected tissue down to sound, unstained wood. Seek help from a professional arborist if unsure of how to perform this surgery. Do not attempt to remove large trunk cankers. Currently, research by the Colorado State University Forest Service shows the usefulness of fungicidal sprays and wound paints to be in question. 


Mites feed on all parts of the trees. They are narrow, very tiny (1/100 inch long), translucent, and have four legs toward the front of their bodies. Adults appear only as a speck through a hand lens. Many mites cause woody swellings or galls, especially around the buds of aspens. Infestations usually occur in early summer, immediately after tree buds open. Under ideal conditions, development from eggs to adult takes 14 days.

Although galls are conspicuous and unattractive, they rarely do any real damage to plants. Furthermore, once galls start, formation is largely irreversible. Under most circumstances, control is not recommended. Heavy infestations that occur repeatedly over several seasons may slow the growth of the plant or make the appearance unattractive.

Most galls are produced by insects that move to the trees as new growth develops in the spring. They can be controlled only with sprays, such as Sevin or Kelthane, that cover the leaves during the egg-laying period. Repeat applications often are needed.

For more information, contact your local Colorado State University Extension Master Gardener Program or visit Colorado State Forest Service - insects and diseases at