Taking an environmentally sensitive approach to pest management


David Trinklein
University of Missouri
Plant Science & Technology
(573) 882-9631

Garden IPM Starts with Fall Cleanup

David Trinklein
University of Missouri
(573) 882-9631

November 21, 2022

minute read

hands picking up a bunch of fallen leaves

Credit: Pixabay

Integrated Pest Management (IPM) is an effective and environmentally friendly approach to pest management that relies on a number of common-sense practices. One of the first tenets of IPM is prevention. It adheres to the age-old advice of Dutch philosopher Desiderius Erasmus who, more than five centuries ago, famously stated that "prevention is better than cure." Any pest or problem in the garden that can be prevented is one less that will need to be dealt with later. For gardeners, prevention begins with fall garden cleanup.

Garden cleanup does more than just improve the appearance of the garden during the (seemingly) lifeless months of winter. It is an important part of preparing the garden for the coming growing season by reducing the amount of disease inoculum, weed seeds and insect infestation that might be present. As mentioned above, prevention is the best cure for any plant-related problem. While disposing of the remnants of this year's garden might not totally prevent problems from occurring next year, it is certain to lessen them.

white powder on leaves

Example of powdery mildew inoculum on lilac leaves. Credit: Missouri Botanical Gardens

Fall clean-up starts with removing all plant debris from the garden and disposing of it properly. Remaining vegetables (other than winter vegetables) and annuals should be pulled. Healthy plant material can be added to a compost pile; debris from diseased or insect infested plants should be discarded. When in doubt, discard plant material removed.

Herbaceous perennials can be cut back to their crowns any time after they have gone dormant. This usually occurs after the first hard freeze of the fall. Mulch those perennials that benefit from winter protection after several freezes have occurred and the soil has cooled. The same is true for winterizing roses.

illustration of rose bush with no leaves being mulched

Grafted roses such as hybrid teas, floribundas and grandifloras should have their graft union protected from cold winter temperatures by mulching. Credit: WikiHow

Additionally, thoroughly weeding garden space in the fall will help to curb weed populations the following growing season. Careful hand or mechanical weeding is best, although non-selective herbicides such as glyphosate can be used on living weeds. However, keep in mind that post-emergence herbicides applied in cool or cold weather take longer to kill target weeds. Using rates at the high end of labeled recommendations is advised whenever the air temperature falls below 65° F.

It has been estimated that one large pigweed can produced between 100,000 and 600,000 seeds. Weeds that already have matured and set seed should be carefully removed from the garden. Carelessly pulling a weed and dragging it out of the garden is a good way to spread seeds and insure a large population of weeds next growing season. Instead, cut the weed and carefully place it in a large plastic bag before removing it from the garden.

Removal of fallen leaves from the lawn is another way prevent future problems. Leaves allowed to accumulate over turfgrass and low ornamental plants can pack down and form a tight mat, particularly during the course of a wet winter. A thick layer of leaves can block sunlight from reaching turfgrass, thus reducing the ability of plants to manufacture food. Additionally, leaves also tend to trap and hold moisture in the plant leaf canopy, increasing the potential for disease outbreak.

leaves covering turfgrass

Unless removed, a thick layer of fallen leaves can have a detrimental effect on turfgrass and small perennials. Credit: Pixabay

In addition to raking, another way to clear the lawn and recycle leaves is to mulch them into the turfgrass. On a dewy morning when the leaves are still damp, adjust your lawn mower to its highest setting and start mowing. By using a crisscross pattern and double-mowing, leaves often can be reduced to the size of confetti. The tiny pieces of leaves will gradually filter into the lawn and begin to decompose. The end result will be the release of nutrients contained by the leaves for use by the turfgrass. Research has demonstrated that a layer of leaves up to six inches in thickness can be mulched into the lawn with no ill effects.

Fall also is an ideal time to improve garden soil. The addition of compost, well-rotted manure or other forms of organic matter is more easily accomplished in the fall when the soil (generally) is more workable. For annual flower beds and vegetable gardens, incorporating several inches of well-decomposed organic matter is consider a "best management practice" for gardens. Limestone and other slowly soluble fertilizers may be incorporated at the same time, if called for by soil tests.

hand placing dirt into a box with a trowel

Fall is an ideal time to have soil tested and to take appropriate remedial measures. Credit: Clemson University

If you are fortunate enough to have a cold frame, hot bed or other "season extender", clean it in the fall. A clean, "ready-to-go" cold frame is more likely to be used next spring than one that is overgrown with weeds and filled with debris. If you don't have a season extender, consider building one as a winter project.

Also, turn off and frost proof irrigation systems. Drain hoses and store them out of the sun. Drip irrigation systems should be carefully removed and stored for use next year. Fall is a good time to clean and store garden tools. Metal surfaces should be free of soil and covered with a thin film of oil before storing. Tools with a cutting edge should be cleaned and sharpened in preparation for next year's growing season.

Power garden equipment such as mowers and tillers can be winterized at this time as well. Check the owner's manual for how this should be accomplished with your mower. If mechanical problems developed over the past gardening season, now is a good time to have them resolved. Garden equipment mechanics are much busier in the spring than in the fall.

hand placing dirt into a box with a trowel

Power equipment such as lawnmowers should be prepared for winter storage at the time of fall garden cleanup. Credit: Pixabay

Additionally, think spring. While the image of this year's garden is still vivid, start making plans for next year. What were the major problems/disappointments of the past growing season and how might they be prevented next year? Which varieties worked well, and which did not? Do those that were disappointing deserve a second chance or is it time to try something new? Since time tends to dull the memory of most people, sketch a planting plan for next year and start to form a gardening "to do" list.

Finally, remember, winter is only 90 days long and next growing season will be here before you know it. By taking a few preventative measures, you are likely to have fewer problems next growing season because of fall garden cleanup.

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REVISED: November 22, 2022