Garden Pro-Tips: September

Your Pro-Tips for September here in the PNW

As summer begins to wane and the first hints of autumn creep into the Pacific Northwest, it’s time to transition your garden for the cooler months ahead. Here are some pro-tips to ensure your garden remains productive and healthy throughout the fall and winter.

1. Divide Perennials

August and September are ideal months for dividing your perennials. This helps manage their size and encourages healthier growth and more abundant blooms next season. Perennials such as goldenrod, monarda, echinacea, and asters can benefit from division now. Carefully dig up the clump, separate the roots, and replant in well-prepared soil. Water thoroughly to help them establish before winter sets in.

2. Erect Cloche or Hoop House for Hardy Winter Greens

To extend your harvest season, consider erecting a cloche or hoop house. These structures provide essential protection for hardy winter greens like kale, spinach, and Swiss chard. The extra warmth and shelter will keep your crops growing through the coldest months. A hoop house is easy to set up using PVC pipes and plastic sheeting, and it can significantly increase the productivity of your winter garden. Using simple covers such as sheets or lightweight plastic can work in a pinch.

3. Harvest Summer Crops

Now is the time to harvest the last of your summer crops. Tomatoes, beans, peppers, and cucumbers should be picked regularly to ensure you get the best flavor and prevent over-ripening. Consider preserving any surplus through canning, drying, or freezing so you can enjoy your garden’s bounty long after the growing season has ended.

4. Look for Blight on Tomatoes; If Seen, Harvest Fruit Immediately

Tomato blight can be a significant issue in late summer and early fall, particularly with the damp conditions common in Washington. Check your tomato plants regularly for signs of blight, such as dark spots on leaves or stems. If you spot any symptoms, harvest all remaining fruit immediately, even if it’s green. Green tomatoes can be ripened indoors or used in recipes like fried green tomatoes, chutneys, and as a tangy addition to baked goods. They are also delicious as a sweet or dill relish.

5. Sow Overwintering Veggies

August and early September are perfect for sowing overwintering spinach, arugula, and cilantro. These cold-hardy greens can survive the winter with minimal protection and will give you a head start on the growing season in early spring. Sow seeds directly in the garden in well-prepared soil, and water consistently until established.

6. Sow Winter Salad Greens

Winter salad greens such as mâche, claytonia, and winter lettuces can also be sown now. These greens thrive in cooler temperatures and can be harvested throughout the winter, especially if grown under cover. Ensure that your soil is rich in organic matter and well-drained to give these greens the best chance to flourish.

7. Transplant Lettuce, Spinach, Chard, Kale, and Other Cold-Hardy Greens

If you’ve started cold-hardy greens indoors or purchased transplants, now is the time to get them into the garden. Lettuce, spinach, chard, and kale are all excellent candidates for fall and winter growing in Washington. Space your plants appropriately to allow for full development and ensure they have consistent moisture. These crops will thrive with the cooler temperatures and shorter days, providing fresh greens well into the winter months.

Check out our September Garden Guide for more information!

With these tips, your garden will continue to thrive as we transition into autumn. By dividing your perennials, setting up protective structures, and sowing the right crops, you can ensure a productive and resilient garden that keeps giving even in the cooler months.