CO-Horts Blog

Thursday, August 13, 2020


The Top Ten Vegetables to Plant in August

Posted by:  Patti O’Neal, Horticulturist and Urban Food Systems Coordinator, Jefferson County


There is still time and August is a great time to get another round of crops into the ground for a bountiful fall harvest.  The first average frost date along the front range as been around the 2nd week of October for most of the past decade.  This gives you nearly 90 days of growing time.  In that time, you can have a bounty of vegetables to enjoy all through fall. 


Here are some of easiest fall crops to grow. 


Lettuce- An easy vegetable to grow.  Leafy varieties are well suited to fall gardening.  The seeds need to be kept moist and the soil temperature mitigated.  Once the seedlings are up mulch the soil to retain moisture.  Lettuce does not appreciate a little frost like its other leafy green cousins and must be protected from frost with frost blanket.   And the varieties are beautiful, colorful and endless!  Red, green, spotted, ruffled, with names like Trout Leaf and Drunken Frizzy Headed Woman. 

Photo Courtesy of Farmers Market Foray

Radishes – One of the fastest, easiest crops to grow.  They can be eaten raw for spicy crunch or roasted or sautéed.  The tops can be made into a pesto.  They like well drained, fertile soil.  Mulch and thin once germination occurs.  They mature in 25 to 30 days.  There are Cherry Belle, Easter Egg, Watermelon, Black varieties and more.

Swiss Chard – Beautiful and versatile, swiss chard can be substituted for spinach in any recipe and offers flavor as well as color with the beautiful stems.  It grows all season long but planting a new crop in the fall gives you a sweeter, tastier addition to sautes, soups, stews or salads.

 Beets – a flavorful, earthy flavored vegetable that can be eaten raw, grated in salads, roasted or sautéed.  Do best if thinned to 3 inches as they grow, but the thinnings are awesome in salads, so don’t waste them.  Plants may be grown for the greens as well as the root and the smaller varieties are great for fall gardens and red and golden varieties thrive here.

 Spinach – Tolerant of many soil types and easy to grow on the plains or in the mountains as it loves a hit of frost and sweetens to a mellow flavor.  Can be harvested as small leaves and it will re-grow between harvests or wait until a more mature size.  At least nine varieties grow successfully here and is a favorite of the fall garden.

                                                 Photo Courtesy of Eden Seeds


Carrots -There are so many varieties but choose those with a shorter-days to maturity quotient.  Carrots tend to take longer to germinate than most other vegetables, so patience rules here.  They like well drained even sandy soil and will require some mulch to make sure the soil does not crust preventing good germination and to keep shoulders from greening as the carrots mature.  Even watering will keep the roots from becoming weirdly shaped. 


Kohlrabi – A fun but unusual vegetable.  Best grown from transplants which are available locally.  Once established, they benefit from a good side dressing of organic matter.  Can be harvested when the stem is 2-2.5 inches in width. 


Parsley – the universal herb that brightens any dish.  It has health benefits you never dreamed of; antioxidants, antibacterial, cancer fighting properties and more.  It is slow to germinate, so keep evenly moist and be patient.  Once it does, you can keep harvested and the plant will produce well into the cold weather and more if protected. 


Asian Greens – Asian Greens are a delectable addition to the fall garden as well as your fall dishes.  They are easy to grow in well aerated soil with a little nitrogen boost. 

Photo Courtesy of Melissa's Specialty Vegetables

Dill, Cilantro – two favorite herbs that love the cooler temps to thrive.  Dill can be a loose canon in the garden, spreading everywhere.  Planting now will give you plenty of delicious leaves for your cooking and pickling without huge flower development which eventually spreads seeds all over.  Then cilantro can be replanted now so you can make all that lovely salsa as tomatoes continue to ripen through the fall.


 Key cultural considerations:

·      Plant varieties that have short days to maturity to be sure to reach full growth and a successful harvest.

·      Most of these crops are leafy and do not require a full 8 hours of sunlight to grow.  So, if you did not have adequate sunlight to grow peppers and tomatoes, you likely will have a great spot for a pot of spinach, chard or kale.

·      These are cool season crops that you are planting in the heat of summer, so the soil is warm as well as the ambient temperatures high.  Keep the soil evenly moist and mulch to keep the seeds cool so that they germinate successfully.  Be diligent and consistent with your watering – take care to not overwater!

·      Once seeds germinate and begin to grow, the cooler temperatures these plants thrive on will begin.  As a matter of fact, these plants are designed to take a hit of frost which concentrates the carbohydrates and makes these vegetables sweeter than their spring counterparts. 

·      Insect pressure can by heavy in the high temperatures of August.  In addition to good cultural care, you may employ season extenders to cover the beds or pots and help young seedlings get off to a good start. 

·      If you are new to season extenders, they can be purchased locally under the name “floating row cover,” “plant protection blanket,” “frost blanket.”

For seedlings, these can be applied directly over the soil until germination occurs and seedlings are up several inches (thus, floating row cover) and if you need deep frost protection later in the fall, it is easy to install hoops from wire or electrical conduit or other re-purposed materials to spread the frost blanket over. 

Photo Courtesy of WI Master Gardeners

 For additional help:

This is a wonderful guide to growing Vegetables in Colorado by Colorado Extension Horticulture agents.  There are tips on specific crops as well as with hints for mountain gardeners.



  1. Thanks Patti. I never thought of replanting cilantro for salsa. What a good idea. Where can I get a copy of the Colorado Vegetable Guide?

  2. Access the link at the end of the article to see the Colorado Vegetable Guide.