In honor of its 10th anniversary, we’re “reprinting” David Garth’s classic article from August 2015 on growing greens in the fall garden, with a few updates to reflect current warmer temperatures. Enjoy!
When blistering mid-summer heat drives us from the garden, it’s time to sit in the shade with an icy drink and dream of cool weather crops that freshen up fall menus. Lettuce and spinach need the milder temperatures of September and October. With some protection, we might bring them to the table in December. Kale, collards and Chinese cabbage improve their flavor with frost and sometimes can be harvested throughout the winter. These crops thrive in cooler temperatures (60-70ºF.) and supply vitamins A and C to our diet; plus they will be ready to eat long after staples such as corn, beans and tomatoes have had their turn.
Fall offers a second chance to perfect those spring veggies that didn’t do as well as expected. All these vegetables need well-drained, fertile soil with a pH of 6.0 – 7.0. Just as with early-season gardening, it takes a little planning with an eye toward fall frost dates where you live. Here’s a guide for extending home-grown nutritious greens beyond summer.
Since the average frost date for Albemarle County, now in Hardiness Zone 7b, is October 25 to November 5, we work back in the calendar to determine when to plant seeds or shop for bedding plants. Determine the planting date by adding the number of days for germination for your variety, the length of time until harvest, and a “fall factor” of two weeks. The fall factor considers shorter sunlight and lower temperatures at this time of year. Total these days and count back from about November 1st to determine a planting date for seeds. Since kale, collards and cabbage are more tolerant of frost and hot weather, exact calculations are not necessary. But, see the note on lettuce and spinach below.
About Frost: Old farmers distinguish light frosts from heavy frosts by the damage done. Many fall vegetables will stand a light frost and even improve their flavor. Frost settles in low spots, so a garden with a slight slope can avoid some damage. When temperatures are dropping below 45Âş F by 10 PM, when the night sky is clear with stars, and the air is dry, you can know that frost is likely.
Kale, Collards and Cabbage: Collard and kale seed can be planted outdoors by August. You can add the seeds to an existing row in your garden. However, since hot summers can make our clay soil hard, you may prefer to create a bed with a little vermiculite and potting soil, either in the garden or in a container designed for planting seeds. One year we received a present of 25 or more Tuscan kale (also called lacinato or dinosaur kale); they started in a flower pot and all transplanted successfully.
Due to summer heat, plant seeds in the garden twice as deep as you would in the spring. A gentle watering or a rain helps with germination. Old farmers would lay a board over the row to conserve moisture, removing the board as soon as sprouts appear. Mulching alongside the plants will help reduce the need for watering until seedlings are well-rooted.
Young cabbages will need to be transplanted either from your garden or from the garden center. Thin kale and cabbages to 6-8 inches apart when they have at least two leaves; collards need at least a foot. These vegetables can withstand the heat of late summer.
Leaves of kale and collards can be picked as they reach 6-8 inches, starting from the bottom of the plant. Leaves of both will grow much larger without losing good flavor and generate new leaves over the season. Cabbage heads can be cut off and eaten when they are firm and the size of baseballs. Space cabbages farther apart for bigger heads; but reduce watering as the heads form and get larger in order to prevent splitting. Light frosts won’t hurt and actually add flavor.
Swiss Chard is another spring/fall crop that manages fall temperature fluctuations well, although it grows throughout the summer. Because the mid-vein of the leaf is tender, it can be used like celery either separately or together with the rest of the leaves. Rainbow chard dresses up the garden when most things are fading from green to brown. Chard needs to be thinned twice, first when it’s 6 inches high and again when 8-10 inches tall — until plants are 8 inches apart. Don’t throw the little guys away, take them to the table. Cut mature leaves of 10-12 inches just above the ground.
With all fall greens, it’s smart to choose varieties with a shorter time to maturity to increase chances of a good result. A light application of a balanced fertilizer helps. Remember that average temperatures are just averages. With our warming temperatures, killing frosts for these hardier greens may not come until January and row covers may keep them alive through the winter into next spring. Stay hopeful.
September is about right for seeding lettuce and spinach. Leaf lettuce is the easiest and fastest to grow and tastes better than the familiar “iceberg” lettuce. Leafy Bibb and Romaine lettuce will all grow in central Virginia, but require slightly different spacing and culture.
A seed mixture of lettuce leaf varieties will offer a rainbow of colors, textures and flavors. Our challenge in central Virginia is that late summer heat can cause lettuce and spinach to bolt and turn bitter. Partial shade or sprinkling in the afternoon will cool plants. On the other hand, these vegetables thrive in cooler fall evenings. Follow Thomas Jefferson’s advice and plant a thimbleful of lettuce every two weeks in well-drained, fertile soil. This ensures a lengthy harvest since leaf lettuce does not keep well. When plants have four leaves, thin carefully since roots are fragile and near the surface. Leave space between them depending on the variety and instructions on the seed packet. Air circulation in the row and keeping soil moist but not soggy helps prevent disease.
Spinach needs much the same conditions and care as lettuce. As a bonus it’s eaten either raw or cooked. Harvest by pinching stems when plants have six to eight leaves. Both lettuce and spinach are more vulnerable to frost than the greens described above, but may bounce back from temperatures no lower than 30ºF. Unlike other greens, spinach will not generate new leaves after harvesting.
Problems:Â Before cold weather drives bugs into hiding, scout leafy greens for nibbling insects. Worms or caterpillars can often be picked off. Row covers help. We want to be cautious about chemical sprays with greens. Insecticidal soap, neem oil and pyrethrins are accepted for organic growing and are less toxic. Good air circulation, consistent soil moisture, leaves that dry before nightfall and crop rotation keep diseases at bay. Overall, we recommend following Integrated Pest Management (IPM) practices and avoiding chemical use whenever possible.
PESTICIDE WARNING:
Pesticides (which include herbicides, insecticides, rodenticides, etc.) are poisonous. Always read and carefully follow precautions and safety recommendations given on the container label. Store all chemicals in the original labeled containers in a locked cabinet or shed, away from food or feeds, and out of the reach of children, unauthorized persons, pets, and livestock. Consult the pesticide label to determine active ingredients, signal words, and proper protective equipment.
Pesticides applied in your home and landscape can move and contaminate creeks, lakes, and rivers. Confine chemicals to the property being treated and never allow them to get into drains or creeks. Avoid drift onto neighboring properties and untargeted areas.
Resources:
“Collards in Va,” https://www.youtube.com/watch?v=6v03TLEyayU
“Fall Vegetables with Succession Planting, Penn State Extension
The Fall Vegetable Garden (PDF), Purdue University Extension
Planting Vegetables in Mid-Summer for Fall Harvest, U of Minnesota Extension
Rodale’s Garden Answers, Fern Marshall Bradley, ed. (Rodale Press, Emmaus, Penn. 1995).
Lead photo: Fall kale crop. Photo by David Garth