The Literary Gardener – September 2015

Departing summer hath assumed
An aspect tenderly illumed,
The gentlest look of spring;
That calls from yonder leafy shade
Unfaded, yet prepared to fade,
A timely carolling.
~William Wordsworth
September, 1819

If your enthusiasm and energy for gardening has waned from this summer’s triple-digit temperatures and smoky haze, then September may be just what you need to capture a second wind. Average temperatures this month drop about 7 degrees and chances of cooling rains increase, so now is the time to get out in the garden to transplant starts for fall and early winter and to sow seeds for over-wintering vegetables.

First, though, attend to late-summer crops by pinching off blossoms from tomatoes, peppers, squash, and eggplant, and pruning growing tips from tomato plants. This will allow the plants to focus their energy on bringing remaining fruit to maturity before killing frosts set in. This is also the time to cover your sunflowers to protect the seeds from hungry birds.

Vegetables to direct seed this month include: arugula, daikon radish, garden cress, kale, leaf lettuce, and mustard and turnip greens. All of these will be ready for harvesting by wintertime. Sow the seeds twice as deep as recommended for springtime planting because late-summer heat can dry out the top layer of soil, preventing seeds from germinating. A mulch dressing will help retain moisture and keep the soil temperature cool enough for optimal sprouting.

Overwintering vegetables that can be direct-seeded this month include: onions, radishes, and spinach. In addition, starts for fall varieties of broccoli can be transplanted in the garden this month, along with sprouting types of broccoli that will be ready for harvesting in winter. Other overwintering vegetables to transplant this month include: cabbage, cauliflower, celery, and garlic.

Also, don’t forget about your flower garden this month. Look around and note gaps you want to fill by planting out new annuals and perennials. For example, my front-yard berm looks great in the spring and early summer, but I need to add some late-summer and fall-blooming flowers for longer-lasting color. I might also want to add some evergreens to add garden interest during wintertime.

Fall-blooming annuals to choose from include: pansies, petunias, nasturtiums, marigolds, gazanias, celosia, amaranth, cosmos, zinnias, sunflowers, and morning glories. Perennials that bloom in late summer and fall include: sedum, silver Artemisia, blue leadwort, balloon flower, ageratum, lobelia, aster, chrysanthemum, monkshood, blue salvia, meadow rue, gayfeather (or blazing star), goldenrod, helenium, coneflower, Joe Pye weed, rudbeckia, Russian sage, and yarrow.

Although annuals won’t survive the winter, most will bloom up until the first hard frost. Some annuals, such as cosmos, nasturtiums, and sunflowers, will self-seed and grow back next year. Transplanting perennials in the garden this month will give the plants time to develop healthy root systems, enabling them to survive winter temperatures. Flowering plants often go on sale this late in the season. Another option is to sow perennial seeds in November and grow them indoors until next spring. Annual flower seeds and starts can be sown next spring and early summer.

Before direct-seeding or transplanting vegetable starts and flowers, be sure to rejuvenate the soil by removing leftover plant debris, moistening the soil, and then using a garden fork to lightly work in a mixture of compost and a balanced fertilizer. Adding a soil inoculant, such as mycorrhizae, to the planting holes will further support the development of healthy roots.

The best time for transplanting is on an overcast day or in the cooler morning hours. Gently untangle rootbound starts with your fingers, moisten the rootball, and then fan out the roots in the planting hole. Also, be sure to keep an eye on the temperatures in September. You may need to protect vulnerable young plants from temperatures that are higher or lower than average with shade cloth or floating row cover.

Let’s take gardening advantage of what 19th century poet Helen Hunt Jackson called the “lovely tokens” this month offers. She writes: “September days are here, with summer’s best of weather and autumn’s best of cheer.”

Photo: Glenn Risley