Best practices for mulching in the fall/spring - Ask Extension
Residents in our community are looking to improve their home lawn maintenance practices. Their questions are:
1- Is leaving the leaves in the gar...
Knowledgebase
Best practices for mulching in the fall/spring #916537
Asked September 05, 2025, 9:47 AM EDT
Residents in our community are looking to improve their home lawn maintenance practices. Their questions are:
1- Is leaving the leaves in the garden beds the best practice for fall or spring mulching?
2- For those who do not choose to leave the leaves as mulch in their home garden beds, what other mulch - pine or hardwood or arborists chips - or others - would you recommend?
3- Do you recommend mulching in spring and fall to keep down weeds in spring and protect plants in winter?
Thank you.
Howard County Maryland
Expert Response
We encourage using fallen leaves, when available, for mulching garden/flower beds, yes. Any biodegradable mulch (pine needles, shredded bark, bark nuggets, wood chips, etc.) is a good option, as it decomposes into soil-improving organic matter that benefits roots, but leaf litter has the added benefit of supporting wildlife in other ways, like providing food and shelter. For non-leaf mulches, an Extension educator at Washington State University advocates for arborist wood chip mulch as the best material, but anything that easiest for you to source and apply should be fine.
When and how often to mulch depends on what the needs of the garden are. For vegetable gardens going fallow for winter, a mulch can be applied as soon as the harvest is done and the crop debris removed (if a cover crop isn't being grown as a live mulch). For flower beds or areas around trees and shrubs, any time of year is fine when the mulch layer has decomposed enough to become too thin to prevent weed seed germination. Mulching in fall can insulate the ground from early cold snaps and slow evaporation during a time of year when rains become/remain irregular, and it can discourage the germination of winter annual weeds (chickweed, bittercress, etc.). Mulching in spring can discourage spring-germinating weeds, though usually the retention of moisture isn't as important (since spring usually has more regular rains or snowmelt), and insulating cold ground might not be desirable for some plants. (It can help with plants you don't want emerging from dormancy too soon, like during warm spells, so it's not a universally bad side effect.)
Generally, mulching or mulch replenishment (topping-off what is needed to restore mulch depth to about 2-3 inches, not entirely replacing what was laid earlier, which defeats the purpose of recycling those nutrients and organic matter) is done in autumn, since it slows soil cooling so roots can continue active growth for longer. However, the timing isn't that critical, and it can be done whenever the situation dictates.
Miri
When and how often to mulch depends on what the needs of the garden are. For vegetable gardens going fallow for winter, a mulch can be applied as soon as the harvest is done and the crop debris removed (if a cover crop isn't being grown as a live mulch). For flower beds or areas around trees and shrubs, any time of year is fine when the mulch layer has decomposed enough to become too thin to prevent weed seed germination. Mulching in fall can insulate the ground from early cold snaps and slow evaporation during a time of year when rains become/remain irregular, and it can discourage the germination of winter annual weeds (chickweed, bittercress, etc.). Mulching in spring can discourage spring-germinating weeds, though usually the retention of moisture isn't as important (since spring usually has more regular rains or snowmelt), and insulating cold ground might not be desirable for some plants. (It can help with plants you don't want emerging from dormancy too soon, like during warm spells, so it's not a universally bad side effect.)
Generally, mulching or mulch replenishment (topping-off what is needed to restore mulch depth to about 2-3 inches, not entirely replacing what was laid earlier, which defeats the purpose of recycling those nutrients and organic matter) is done in autumn, since it slows soil cooling so roots can continue active growth for longer. However, the timing isn't that critical, and it can be done whenever the situation dictates.
Miri
