Normally, this time of year feels like a missed deadline in the garden: I am rushing to pick, process, and prune, turning over beds and trying to get ahead of fall cleanup, which makes me loathe the onset of September. But all that work gleaning, collecting seed, seeding green spaces, and changing over the beds now will make sure your garden is in good shape for next year. Here are all the gardening tasks you should be doing in September.
I'm choosing this word deliberately over "harvesting" this year. After a summer where everyone I know has been plagued with fungi and viruses in the garden, it's a reminder that harvesting the spoils of your garden is about our own benefit, but it also removes a vector of disease from our beds. After many years of "chop and drop" (where you chop down spent plants at ground level and leave them to compost in place) evangelism, it's become a common topic of conversation amongst gardening groups to ensure you remove yard waste from your garden beds to prevent the spread of soil-borne diseases. So this year, I'm making an effort to get into my beds and chop the plants and remove them. Diseased plants go in the trash (not compost, even city compost) and healthy plants go into my compost pile. Even though they'll end up in roughly the same place after composting (back in the beds), the heat from compost pile will kill many of the viruses that could be present.
Instead of leaving fruit to rot in the beds, it's advised to be more deliberate about which plants you should propagate for next year. The solution is seed collection, an endeavor I've become a lot more serious about in recent years. While the cost of seeds is a great justification of this, finances aren't my primary motivation. By choosing the plants that have done the best in my yard, and doing so year after year, I am actually creating my own strain of that fruit that is bred to do well in my yard. After all, it's already thrived in those conditions.
Some plants make it easy for you: green beans, sunflowers, beans, and peas, for instance. They dry themselves outside and present themselves to you ,waiting to be collected. A second group of vegetables requires more patience: celery, lettuce, parsley, cilantro, cabbage, fennel, and broccoli. These vegetables have to be allowed to go to seed, which means they flower, and those flowers eventually bear seeds. Once the seeds make an appearance, you collect them. They won't be dry—you'll need to spread them out on a plate and place them in a spot with decent airflow (I put them in front of a fan). Then there are the nightshades: tomatoes, eggplant, and peppers. These are the most expensive seeds to buy, and are well worth saving. Find the best example of a fruit from the healthiest plant to sacrifice. Cut it open and scoop out all the seeds, placing them and the accompanying "goop" that surrounds the seeds into a jar with a little water, and allow that water to ferment for a day or two. Then drain the seeds in a colander, onto a sheet of paper towel and dry as you would the other seeds. It's OK if the seeds stick to the paper towel—it won't matter when it's time to germinate.
Flower seeds follow the same pattern. All flowers produce seeds in different ways, from poppies, which store their tiny seeds in dried pods, to foxglove, which shakes seeds from the entire length of its stalk. For any flower you want to save seeds for, pay attention at the end of the season to the flowers and look for the seeds or conduct an internet search for how to save those seeds specifically.
September has the right mix of heat and rain in most places, which makes it ideal for germinating seeds. If you have a traditional lawn, it's time to take advantage of the conditions, but since prep will take time, get started now. The same is true of eco lawns: If you're going to overseed clover or other ground covers, order your seeds now.
As you start bringing summer crops to an end, you have to decide what to do with the garden beds for fall and winter. I am a huge proponent of all-season gardening, which means you can put fall and winter crops in now. But there's a strong argument for occasionally letting your beds rest, even if it's only one or two beds out of your lot. In the resting beds, clear them exceptionally well of any weeds, and then give them a hefty dose of compost, and some myco powder (mycorrhizal inoculant, which will spawn mycelium in your soil). Then, plant a cover crop suited for your bed. There's oil driller radish, if you need to break up soil, fava beans, which bring a hefty dose of nitrogen to the soil, clovers, and grasses. Your local nursery will have options appropriate for your zone. When spring rolls around, you'll chop the plants, allow the roots to compost and plant your summer crops into your recovered bed.
While your entire yard is going to get cleaned up in the coming months, I make sure to start with my berry arbor. You want to do this pruning while you can still tell which vines are green (new growth) and brown (second-year growth that should be pruned away). I tidy up the rows (meaning the vines that have sprouted out of place get plucked), chop everything to a level height of about six feet, and tuck all vines back into the trellis. Doing this now ensures a far more prolific and accessible fruit harvest next year.
You can get a head start on other fall tasks, but realistically, most people are far too busy still processing the vegetable and fruit in their yard. There'll be plenty of time come next month.
