September’s seasonal conditions signal the summer crops to finish out the season before frost comes. 

In Colorado, we fell below 13½ hours of daylight on August 20, which causes many vegetable crops to produce flowers and seed for the next generation. This time of year, we commonly see annuals bloom one last time while perennials begin the process of storing nutrients in their roots so they can grow again in the spring. 

We will continue to lose daylight until December 20. Many crops still thrive with less than 13½ hours of light, but most will stop flowering when we hit 10 hours of sunshine on November 17. 

As winter rolls in, commercial growers protect their crops with hoop houses, high tunnels and heated greenhouses. As hobby growers, we must rely on timing and crop selection to keep the fresh food coming.

Now is time to start your winter garden

We have until about September 15 to get fall and winter crops established. The goal is to have strong teenaged crops heading into late October and early November, when overnight temperatures really drop. Planting seeds in late September and early October doesn’t provide enough time for plant growth, and small seedlings can’t handle the stress of reduced daylight hours and colder temperatures. Adding some wire hoops or tomato cages and covering them with plastic can help insulate plants, but the reduction in daylight hours is hard to offset.

It’s important to note that seed packets list the days to maturity heading into summer. The same crop that takes 40 days to mature when it’s planted in May can take 50 days to mature when it’s planted on September 5, 60 days when planted on September 20, and a full 100 days if planted on October 3. 

In August and early September, plant seeds weekly for succession crops—cutting leaves from one plant, then the next, then the next while the first plant re-grows. We need to ratchet up the seeding time because plant growth will slow and we want a steady supply of food. 

By September 10, plant seeds every four to five days. By September 20, plant seeds every three days. After September 25, juvenile plants are in danger of freezing.

What to plant

Our selection of winter crops is more extensive than most people realize. I prefer to plant carrots and onions in August, but short-season and baby carrots or green onion seed can be planted now. 

Bulls Blood beets make a vibrant addition to any winter dish because the leaves turn deep maroon as winter sets in. There’s also a wide variety of radishes to choose from, such as white icicle, pink China rose and purple daikon. Leafy crops like lettuces and spinach also do well in cooler seasons. 

The most popular fall and winter crops are kale, chard, pak choi and tatsoi, as they all have thicker leaves to hold up to cold nights. Additionally, these crops tend to have an upright growth pattern, which is beneficial even when the sun is lower in the sky in the fall and winter.  

Mache, or corn lettuce, and claytonia are two winter greens that thrive in our climate. They won’t grow in the summer, but they make great salad greens and offer fun textures for cooking. They are great to harvest when everything else in the yard is dormant and brown.

Lastly, September is a good time of year to dig up culinary herbs and put them in pots. Leave the pots outside with partial shade so the plants can recover from the transplant shock. Then by the first week of October, bring them inside as potted plants so that fresh mint, chives, dill and basil can be enjoyed throughout the holiday season.

For further guidance on starting your winter garden, I recommend reading “The Winter Harvest Handbook” by Eliot Coleman.

Don’t miss Bryan’s FREE presentation “Backyard Composting” at Mesa County Libraries’Discovery Garden, 517 Chipeta Ave., Grand Junction, from 6-7 p.m. on October 4. 

Send your gardening questions to Bryan in care of he BEACOn, or email him directly at [email protected]