September is a busy month for committed edibles gardeners. Harvesting, cleaning up, final planting for fall, early winter harvest, and cover cropping or mulching for beds that are finished for the season. We’ll touch on each area to help you plan your actions.
Harvesting
Many summer vegetable plantings will be reaching the end of their productive lives. It is a judgement call on when to stop the harvest and remove plants. It depends on plant condition, pest impact, and intentions for that garden space’s next phase. Harvesting when fruits and vegetables are young can help keep plants going a bit longer. Tomatoes can be picked as soon as color starts to change to minimize pest damage, while maintaining most “summer tomato” qualities. If you’re picking tomatoes early, place them on and cover with newspaper. Keep them at room temperature and check them daily. Some folks include bananas or apples with the tomatoes since their ethylene content can speed the ripening process.
This is also the time to optimize late season herb harvest. Pinching flowers will help prolong leaf production. Plants can be dug up and potted or cut and rooted to be moved inside. Alternatively, they can be cut for immediate use or preserved by freezing or drying.
Planting
In our local hardiness zone 7a, some produce and vegetables can be planted through mid-September. These include beets, kale, collards, kohlrabi, leeks, and turnips. Spinach, lettuces, mustard and radishes can be planted until the end of the month or even into early October, depending on weather. The earlier they are planted the better, since growth will slow as days shorten and temperatures drop.
Many pests will continue attacking plants until frost. After that, the low temperatures will harm the plants. Picking insects off plants and spraying them can help control pests. Row covers can protect new plantings from fall predators. Row covers can also extend the growing and harvest times for the cooler weather crops. For more mature plants that are already susceptible to pest damage, row covers are not a good idea until after frost kills the pests. A row cover can provide a 4 to 5 degree temperature benefit and extend the growing season for a variety of greens, spinach, lettuces and other crops. Check out this Garden Shed article for simple row cover construction ideas.
If you have been struggling with pests this year, a great all-purpose source for pest identification and treatment options is the Home Grounds and Animals: 2023 Pest Management Guide from the VA Cooperative Extension.
Preparing Beds for Winter
If you are finished for the year, this is the time to clean up, amend soil, and protect soil for the winter.
Fall is a great time to do a soil test. Identifying needed amendments and adding them now, provides a head start for strengthening the soil by spring.
Next, thoroughly clean up the garden area. Removing spent plant material is essential to minimize wintering-over pests and disease-carrying vegetation. It is best to bag and dispose of any diseased plant materials. Clean material can be chopped up and composted or spread on the soil and allowed to decompose over winter.
Once beds are cleaned, best practices are to either cover crop or mulch the growing beds. Prior to that, smooth the beds and add amendments recommended on the soil test.
Next, choose whether to cover crop or mulch. While cover cropping is best, adding 4+ inches of organic mulches like compost, chopped leaves, leaf mold (partially decomposed leaves), and/or aged wood chips, will protect the soil during winter and add organic matter over time.
Cover crops bring additional benefits, including building soil structure, reducing erosion and compaction, weed suppression, adding organic matter, and in the case of legumes, fixing atmospheric nitrogen for plant use. There are a couple of basic cover crop choices: winter-killed and winter-hardy.
- Winter-killed cover crops die out after a few hard frosts, but their root and surface biomass help hold the soil and they can be used as mulches or tilled under in spring. Oats, field peas, forage radishes, and rapeseeds are common types.
- Winter-hardy cover crops will either grow through or go dormant in winter but resume growth in spring. They should be cut in spring prior to going to seed, with the greens composted, used as mulch, or, if you insist on tilling, tilled into soil as a green fertilizer. If greens are tilled in, allow 2 or 3 weeks after tilling to let decomposition start prior to planting. Winter-hardy choices include winter rye, winter wheat, hairy vetch, Austrian winter peas, and crimson clover.
- Mixed Covers: Regenerative farmers report benefits from mixed cover crops that diversify the soil. A mix used successfully on Piedmont Master Gardener projects includes crimson clover, forage radishes, and annual ryegrass. If planted by mid-September, the radishes will penetrate deeply into the soil before being killed by frost, opening the soil and depositing valuable organic matter. The clover and ryegrass will go dormant in winter and revive in spring, adding nitrogen and root mass to the soil. They can be cut during the flowering stage, prior to seed formation, and allowed to rest for a couple of weeks before planting. The cut vegetation can be used as a mulch or removed and composted.
- These techniques blend well with converting your beds to “No-Till” gardening. For more info on this proven effective and burgeoning soil management practice, check-out the Garden Shed article No-Till in the Home Garden: Why and How.
Preparing New Beds
If you are planning a new garden or garden expansion for next year, fall is a good time to begin preparing soil. Tilling to remove or bury surface vegetation, adding organic matter, and mulching or cover cropping prior to winter are good preparation for next year. The picture above shows a new garden area operated by New Roots Charlottesville, our local arm of the International Rescue Committee, a PMG community garden partner. The surface grass in the bed has been tilled under and volunteers are preparing the surface for a winter hardy cover crop planting. Additionally, based on a soil test, lime was spread over the area to raise the low pH.
More information on cover crops can be found in Cover Crops and Cover Crops and Green Manures in Home Gardens from the Maryland and Minnesota Extensions respectively.
Another option, which doesn’t require digging or tilling, is sheet mulching. It involves moistening the base soil, covering it with an organic barrier like newspaper or flat corrugated boxes, then adding six or more inches of a mix of organic materials including leaves, soil, compost or aged wood chips, topped off with a few inches of straw to manage moisture and reduce weeds. If done in the fall it should be ready for direct planting in the spring, although the decomposition rate is a function of the materials used. Chunky, woody materials take longer to get ready than mulched and decomposed matter. Find detailed guidance in the video Sheet Mulching: Lawn to Garden Bed in 3 Steps from the Penn State Extension.
General Tips
Garlic is best planted during October. Now is a good time to purchase seed bulbs before local retailers sell out. Internet suppliers offer more variety for experimenters or connoisseurs. The article Growing Garlic – Fall Planting from the Penn State Extension provides a concise summary of garlic selection, planting, and care.
Give your tomato plants one last feeding. Compost tea or fish emulsion should give them the extra energy they need to make that final push at the end of the season. Pinching off small green tomatoes and any new flowers will channel the plant’s energy into ripening the remaining full-size fruit.
Don’t cut asparagus ferns (stalks) until they turn brown and dormant. This is typically later in the fall. Best to give the plants time to store photosynthesized nutrients in the roots to fuel spring re-growth.
If you’ve been lax in your garden documentation this year, tour your garden and make notes on varieties grown, successes, challenges, and chores, so that you can learn for next year. Make a sketch showing the location of this year’s plants to guide rotation next spring, an important pest and disease management practice.
Continue to weed the garden to prevent the weeds from going to seed and germinating next spring. Keep the strawberry patch weed free. Every weed you pull will reduce labor next spring.
Pick pears when green and hard ripe. Store in a cool, dark place to ripen.
Check peach tree trunks and just below the soil at their base for borer holes. Probe the holes with a wire to kill the borers.
Remove two-year-old canes from raspberry and blackberry plants at ground level to reduce overwintering of disease. Fertilizers containing potassium, phosphorus, and magnesium or calcium can be applied, but do not cultivate or irrigate at this time of the year.
Fall weed control around fruit trees is crucial because weeds act as hosts to overwintering insects.
Plant lavender seeds in the fall for spring germination.
In any case, enjoy the fall gardening season. Cooler weather, reflecting on the past season and making preparation for a better next year can be very satisfying. As usual this year, our gardens have been a wonderful diversion. See you next month at The Garden Shed.
Sources:
“Gardening by Month–September,” Missouri Botanical Garden, http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/gardening-by-month/september.aspx
“Monthly Horticulture Tip Sheets — Herbs, September,” Va. Coop. Ext. Albemarle/Charlottesville, https://albemarle.ext.vt.edu/content/dam/albemarle_ext_vt_edu/files/hort-tip-sheets/9-14-herbs.pdf
“Monthly Horticulture Tip Sheets — Fruit and Nuts, September,” Va. Coop. Ext. Albemarle/Charlottesville, https://albemarle.ext.vt.edu/content/dam/albemarle_ext_vt_edu/files/hort-tip-sheets/9-14-fruits-nuts.pdf
Virginia’s Home Garden Vegetable Planting Guide: https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/426/426-331/SPES-170.pdf
VCE September tips for Fruits and Nuts: https://albemarle.ext.vt.edu/content/dam/albemarle_ext_vt_edu/files/hort-tip-sheets/9-14-fruits-nuts.pdf
Season Extenders and Growing Fall Vegetables (psu.edu): Advice on growing fall vegetables and how to protect plants from the cold and pests.
