September is harvest time! And, it marks the beginning of slowly putting the garden to bed.

Garden Checklist

Tidy up flower beds by cutting back perennials that are done blooming, and divide perennials as needed. Replace perennial plants, like lavender, as desired to give them time to establish before winter. Now’s also a good time to plant cacti.

Take cuttings from the plants you want more of, so you can establish them indoors in pots through fall and winter.

Leave winter squash on the vine as long as possible, harvesting just before the first frost. This will allow them to sweeten! Cut squash from the vine carefully, leaving two inches of stem attached if possible.

All life in the garden begins below the surface. Even after seeds have sprouted, crops have grown and bounties have been harvested.

As we begin to pull plants out of the garden this month, we’ll likely leave behind areas of bare soil. Rather than leaving soils exposed and vulnerable to sun, wind and winter cold, we can use cover crops and mulch to protect and nourish garden beds.

Cover crops

Cover crops protect the soil from the elements through wintertime. They also add crucial organic matter to the soil, increase fertility, improve structure to prevent soil erosion and compaction, and help suppress weeds in the spring—depending on what kinds of cover crops you plant and where you live.

Winter-killed cover crops die from frosts during the winter. Sown in summer, winter-killed cover crops will grow rapidly, then die back after a few hard frosts. The plant and root mass will add organic matter to the soil and hold it in place until spring.

Winter-hardy cover crops stay alive through winter and thrive again in the spring. These can be annual or perennial plants that add fertility to the soil and provide a living mulch for your garden beds.

Using cover crops in your garden will do wonders for the health of your soil. I love the way this practice mimics Nature, creating a bridge between fall and spring and transforming our gardens into full-circle garden ecosystems.

Our Western Slope climate offers us the opportunity to explore both winter-killed and winter-hardy cover crops. Hairy vetch and clover are two commonly used perennial cover crops. With vigorous growth, they outcompete weeds. Their deep roots loosen compacted soils and fix nitrogen along the way.

Oats, peas, buckwheat, ryegrass and daikon radish are some of the many options available for winter-killed cover crops. These fast-growing annual plants each benefit soils in different ways through nitrogen-fixing, “tillage” and winter protection.

Use multiple winter-killed cover crops and evenly mix them with some winter-hardy cover crops for a range of effects. By sowing a mixture of seeds, you’ll learn directly from your soil what it needs by observing the crops that flourish.

You can even mix in an edible crop like arugula or kale that will survive winter and provide you with delicious greens during winter and in early spring. Sow arugula this month alongside other cover crops or by itself in a patch of soil, and leave the roots in as you harvest. Young greens will pop up in the cool of fall, and growth will slow as winter begins. Arugula won’t mind being under a blanket of snow, and you can even harvest some arugula greens through winter, incorporating frost blankets if needed.

Mulch

We can encourage decomposition by covering bare soils with mulch. Mulch can be any type of organic matter such as leaves and grass clippings. Opt for plant material that hasn’t been sprayed with herbicide so that you’re feeding your soils nutrient-rich material instead of harmful chemicals. Even better, preface your layer of mulch with a juicy layer of compost or alpaca manure.

At the end of the day, nearly any mulch is better than no mulch, so play around with what works best for you. Your garden will likely be happier for it.

Let Nature’s continuous cycle influence your garden, and you just might find yourself more deeply engaged with fall and every other season.