The Master Gardener

Do's and don'ts for ending the gardening season.

Fall has begun, and for many gardeners this signals the end of their gardening season. We’ve all been told, either formally or informally, that now it’s time to “clean up” our gardens. Whatever that means.

Well, in fact, it can mean several things.

There are cleanups and jobs that go beyond a cleanup. There are some garden cleanup jobs that maybe we shouldn’t do at all. Finally, we should consider if we really want our gardening season to be over this time next year.

End-of-season Do’s

1. Remove your old vegetable plants. Vegetable plants left in the garden over winter become the place for insects and disease to take root.

2. Don’t compost tomato and pepper plants. By the end of season, they tend to become more prone to disease and can carry that on to next year if given the chance.

3. Don’t compost any plants that appear to have been diseased.

4. If you are leaving carrots or other root crops in the ground for winter harvest, be sure to mark the rows, and cover them with a thick layer of straw or hay after the first frost.

5. Do a final weeding. Weeds left in the garden can go to seed, producing many more new weeds in the spring.

6. Rake and clean up leaves under your rose bushes to eliminate a potential breeding ground for insect pests and fungal diseases like powdery mildew.

7. Pick up fallen fruit from under fruit trees for the same reasons.

8. If you’ve not done so already, dig up and store summer bulbs like dahlias and cannas.

9. Plant next season’s garlic crop before the end of October.

10. Have a soil test done. Then add the lime, or other amendments, as recommended by the soil test. Top off with organic mulches and incorporate everything into the soil. The amendments will begin to disperse and the mulches will break down before the next planting season.

11. Finally, cover it all back up with a thick layer of organic mulches (shredded leaves, compost or straw) or a cover crop like annual rye. They will serve as a barrier to weed seeds finding a home in your garden and can reduce the loss of topsoil to heavy fall and winter rain and wind.

End-of-season Don’ts

1. Fall is not a good time to prune. Decay fungi spores will be spreading in the fall. And, because growth is slowing in the fall, pruning wounds heal slower. Combine those two and you increase the potential for fungal diseases invading your trees and shrubs.

2. Fall is also not the time for fertilization or watering, which can stimulate new growth at a time when the trees or shrubs should be allowed to enter dormancy. One exception might be a fall lawn fertilization to stimulate root growth. And, in case of a dry fall, broadleaf evergreens (such as rhodi’s and hollies) need to be well hydrated (watered) before the ground freezes in winter to minimize the risk of winter dessication.

End-of-season cleanups to reconsider

1. Resist the temptation to “clear cut” everything down to the ground. Leaving the ornamental grasses and perennial flowers standing will provide overwintering habitat for beneficial insects and protective cover and food for many birds.

2. Leave some seed-bearing but spent blooms for the birds. They love the seeds of coneflowers, sunflowers and black-eyed Susans. I have a stand of purple coneflowers in a front bed. From later summer on, if I have to go out the front door, I’m likely to see some bright goldfinches flying out of the bed to the cover of nearby shrubs.

3. “Winter Interest” is a landscape term meaning that there’s something interesting to look at during the cold season. That can mean grasses, red twig dogwoods or evergreens of some kind. But winter interest isn’t just for us, but also for the birds, butterflies and beneficial insects living in the garden. A lot more will be going on out there if you leave parts of the garden up until spring.

Finally, ask yourself whether you want next year’s gardening season to end at cleanup time. There are many cool-season crops that, given a protective covering blanket when necessary, will survive and grow through many frosts. Many root crops, greens and even sweet crunchy snow peas can grow and mature in the fall. Add a small cold frame and you can have fresh picked greens in the new year.

Have a question? In Washington County, call the Master Gardeners office at 724 228-6881. Follow us on Facebook. Also consult the Penn State Extension website at extension.psu.edu/plants/master-gardener/counties/washington for additional information.