September in the Edible Garden

September in the Edible Garden

  • By Ralph Morini
  • /
  • September 2020-Vol.6 No. 9
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September is a busy month for committed edibles gardeners. Tasks include harvesting, cleaning up, final planting for fall,  early winter harvest, and cover crop planting for beds that are finished for the season. We’ll touch on each area to help you plan your actions.


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. Picking when fruits and vegetables are young can help keep plants going a bit longer. Items like tomatoes can be picked before fully ripe to minimize pest damage, while maintaining most “summer tomato” qualities. There are a number of ways to ripen green tomatoes off the vine.

This is also the time to consider how 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.


In our local hardiness zone 7a, some produce and vegetables can be planted through mid-September. These include beets, kale, collards, mustard, kohlrabi, leeks, lettuce, radish, spinach and turnips. The earlier they are planted the better, since growth will slow as days shorten and temperatures drop.

Homemade row cover over kale patch.  Photo:  Ralph Morini

Pests like cabbage worms continue to attack brassicas including kale and collards until the first frost. Protecting new plantings with a row cover can minimize pest damage while offering a 4-5 degree temperature benefit and longer growing period after frost. Check out this Garden Shed article for simple row cover construction ideas.

Preparing Beds for Winter

If you are finished for the year, it is good to do a few things to prepare beds for next spring. First task is to 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 plant material that might harbor pests or diseases.

Once cleaned, it is good to add organic matter in the form of compost, mulched leaf litter, or organic fertilizers, providing decomposition time to make nutrients plant-accessible by next planting season. If you aren’t planting a cover crop, mulch beds with an organic mulch like straw, chopped up leaves or aged wood chips

Best practice is to plant a cover crop and keep live roots in the soil year round. Cover crops bring several benefits including building soil structure, reducing erosion and compaction, suppressing weeds, 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, oilseed radishes, and rapeseed are common types.
  • Winter-hardy cover crops can 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 tilled into soil as a green fertilizer. If greens are tilled in, allow 2 or 3 weeks after tilling for decomposition prior to planting. Winter-hardy choices include winter rye, winter wheat, hairy vetch, Austrian winter peas, and crimson clover.
  • Mixed Covers: Some farmers report positive soil effects from mixed cover crops that bring diversity to the soil. Check out your options from wherever you purchase your seed.

New fence and beds ready for organic matter additions. Photo:  Ralph Morini

If you are planning a new garden or garden expansion for next year, now is a good time to begin preparing your soil. Tilling to remove or bury surface vegetation, adding organic matter, and mulching or cover cropping prior to winter will put you in good shape next year. The picture above shows my own expansion. I turned the surface grass under to add some badly needed organic matter to my clay subsoil. Planting a cover crop this month is the next step.

More information on cover crops can be found in earlier Garden Shed articles including Cover Crops from September 2015 and Minimum Till Cultivation from the February 2019 issue.

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 gourmands. For additional information, check out the article on growing garlic in the October 2015 issue of Garden Shed.

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.

Journal noting crop locations to inform rotation next year

If you’ve been lax in your garden documentation this year, tour your own vegetable garden and make notes on this year’s varieties, successes, challenges and chores, so that you can learn for next year. Make a sketch showing the location of this year’s plants to be used next spring for rotating your crops, an important pest and disease management practice. 

Continue to weed your garden to prevent the weeds from going to seed and germinating over the winter and spring. Keep the strawberry patch weed free. Every weed you pull will help make weeding easier next spring. 

Pick pears when green and “hard ripe” — allowing them to finish ripening off the tree. Store in a cool, dark place to ripen. 

Check peach tree trunks and just below the soil at their base for borer holes. Probe any 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.

Whatever you do or don’t do, enjoy the fall gardening season. Cooler weather, reflecting on the past season, and making preparations for a better next year can be very satisfying. This year, especially, our gardens have been a valued diversion. See you next month at The Garden Shed. 


“Gardening by Month–September,” Missouri Botanical Garden,

“Monthly Horticulture Tip Sheets — Herbs, September,” Va. Coop. Ext. Albemarle/Charlottesville,

“Monthly Horticulture Tip Sheets — Fruit and Nuts, September,” Va. Coop. Ext. Albemarle/Charlottesville,

Virginia’s Vegetable Planting Guide:


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