September in the Garden

September in the Garden

September has arrived in the PNW with (hopefully) a bountiful summer harvest of fresh fruits and veggies. This month will be a busy one in your garden (and your kitchen!), while you transition your garden to overwinter crops, sow winter salad greens, and harvest and preserve your summer bounty. Remember to take the time this month to enjoy all the work you put in this season!


September is the ideal time to prepare the soil and plant overwintering crops. Planting overwintering veggies late this month is ideal, but you first need to prepare your soil. First, remove any residual weeds. Before sowing your overwinter crops, chop and turn over your summer crops and cover for a week or two. The decomposition of these summer plants will help provide necessary soil nutrients to your overwinter plants. Don’t forget to provide your overwinter crops with a little space by thinning them out once they are a few inches high.  If you don’t plan to plant an edible winter garden, sow a cover crop (such as crimson clover, fava beans, pea/oat or buckwheat) to enrich the soil with nitrogen for next year’s vegetables and keep weeds out over winter.


As with the previous month, watch closely for apple maggots this month. The brownish-grey tunnels they create can devastate your beautiful apple crop. While it may confuse some, apple maggots are actually a fly that lays its eggs under the skin of apples. When the larvae hatch, they tunnel into the apples, creating the brownish-grey tunnels and rotting your fruit. To prevent these pests naturally, consider using sticky traps like the ones we carry in-store. The flies are attracted to the apple lures and ensnared in the sticky coating. Additionally, it is recommended that you clean dropped fruits regularly.

Slugs also continue their reign of terror this month. Be sure to set out Sluggo Snail and Slug to keep them under control.

Edible Gardening:

Winter vegetable gardens are the easiest! Plant, water once in awhile (fall rains please), harvest a little at a time because it all grows very slowly. If you haven’t already, early September is your last chance to sow your under-cloche winter greens. These greens can be harvested throughout the winter, providing a steady stream of fresh veggies for your table. Veggies like garlic, arugula, spinach, chicories, radicchio and cabbage are great hardy options. Try something new this year from the Culinary Breeding Network featured in the Kitchen Garden greenhouse!

In late September, you will need to plant your overwinter veggies after preparing your soil as directed above. These seedlings will enter stasis when the weather turns cold. The goal is to slowly grow small, 1-2 in. plants before stasis begins. 

Outside Plants and Flowers:

Growing and planting season is still in full swing for some late summer annuals and perennials. For example mums, agastache, echinacea, and black-eyed susans will continue to provide more color well into fall. Pansies will be the one flowering perennial to bloom fall through late spring. Consider planting native plants too, such as Pacific aster for color and habitat through October (see all natives here).

September is also the time to plant bulbs for your spring show. Get your tulips and daffodils in the ground this month and early next month before it gets too cold.  Our large collection of spring-flowering bulbs arrive mid-September, ideal weather for humans to plant before the rains. Bulbs are an inexpensive way to add year-round pollinator plants by selecting flowering periods from spring through summer.

Similarly, now is also a great time to plant conifers, trees, shrubs and perennials. The warm rains often experienced in early September can help to loosen the soil, making digging easier.  Warm soils help the new transplants start to root out, but air temperatures are cooler to slow top growth as the plants head toward winter dormancy and focus on root growth.