University of Maryland Extension

October- Soil, Fertilizer, Mulch, and Compost

soil and an earthworm

(More tips from HGIC)


  • Bare soil is prone to erosion especially over the winter and should be covered with mulched leaves, cover crops, groundcovers, or turf.

  • Avoid the temptation to turn over or dig into wet soil. Tilling wet soil can cause it to become cloddy and brick hard when it dries out. How do you know when your soil can be turned or tilled? One test is to form a clump of your soil into a ball. Bounce it up and down in your hand a few times. If it breaks apart easily it’s probably OK to dig!
  • Poor, compacted soils can be improved through the generous addition of organic matter. Spade or till in a 6-8 inch layer of compost for new flower and vegetable garden beds.


  • Keep leftover bags of fertilizer wrapped up securely in heavy plastic bags or solid containers. Rodents may chew holes in fertilizer bags.
  • Help protect the Bay by using fertilizers wisely. Fertilizers and lime should be applied in accordance with soil test recommendations. Overuse of nitrogen and phosphorous fertilizers may contribute to groundwater pollution. To prevent nutrient pollution of groundwater and the Chesapeake Bay keep fertilizers off hard surfaces like driveways and sidewalks. Be cautious when fertilizing areas of your yard that border these hard surfaces.


  • Mulches should be applied only 2-3 inches deep around ornamental plants and kept away from shrub and tree trunks. Established, mature shade trees do not benefit much from being mulched, except to keep mowers from bumping into their trunks. Mulch perennial beds, trees and shrubs with fallen leaves to help protect crowns and shallow root systems from severe cold weather. Don’t begin mulching your perennials until after the first hard freeze- around late-November. This will help keep soil from freezing and thawing around plant roots.


  • Fall is a good time to start a compost pile by mixing together spent plants, kitchen scraps, fallen leaves, old mulch and grass clippings. Shred your materials with a lawnmower, string trimmer or machete to speed-up the breakdown process. Keep twigs, branches, and other woody materials out of the pile. (video)
  • Barrel and tumbler type composters work well in small spaces but need to be closely monitored to ensure a proper mix of green and brown materials and adequate moisture levels. A disadvantage of barrels is that they are too small to heat up quickly. Compost piles should be at least one cubic yard in volume to heat up properly. 
  • Consider placing a tarp or lid over your compost pile to prevent waterlogging and nutrient leaching. Be sure to bury kitchen scraps deep inside your outdoor compost pile.
  • An even mixture of green, high nitrogen and brown, high carbon materials is necessary for rapid composting. Grass clippings and spent plants from the flower and vegetable garden provide a good source of high nitrogen, green materials for the compost pile. Fallen leaves and old straw mulch are good sources of high carbon, brown materials.
  • When you have a particularly serious insect or disease problem in your garden, do not compost the affected plants.
  • Here are some ideas for dealing with fallen tree leaves:
    • Shred them with a mulching lawnmower and leave them in place (as long as they don’t completely cover your grass.)
    • Shred them and add them to your compost pile.
    • Cover your garden soil with shredded leaves.
    • Use them to mulch perennials, trees, and shrubs.
    • Run them over with a mulching mower, bag them up and use them as a mulch next year.
Maintained by the IET Department of the College of Agriculture and Natural Resources. © 2018. Web Accessibility