University of Maryland Extension

Summer Soil, Mulch and Compost Tips

mulched vegetable garden
Baltimore urban garden mulched to be weed-free. Photo: J. Traunfeld

(More tips from HGIC)


  • Have your soil tested, if you have not had your lawn or garden soil tested for the past 3-4 years. Many plant problems can be solved by correcting soil deficiencies. Watch our video to learn how to collect a soil sample.
  •  Earthworms are a sign of healthy soil and are normally seen in the greatest numbers in fall and spring. Adding organic matter in the form of composted leaves, manure, grass clippings, etc. will improve soil structure and attract earthworms.
  • 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.


  • Maryland summers typically include hot, dry weather. A good mulch covering will help plants survive the stress of summer and keep weeds in check. To be effective mulches should be applied only 2-3 inches deep around ornamental plants and kept away from shrub and tree trunks. Mature trees do not benefit from being mulched except to keep lawnmowers and string trimmers at bay.

  • Select pine bark or hardwood mulches, not wood chips, for use around your home to minimize the possibility of attracting termites. Avoid any hardwood mulches that contain chunks.


  • 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. Shred your materials with a lawnmower, string trimmer or machete to speed-up the breakdown process. Keep sticks, roots and woody stems out of your compost pile. They take too long to breakdown and make it difficult to turn the ingredients.

  • Finished compost is the very best starter material for a compost pile because it contains nitrogen and a huge number of microbes that help transform organic matter into compost.

  • Many kinds of interesting invertebrates live in a compost pile including manure worms, centipedes, millipedes, pill bugs, and pseudoscorpions. They are part of the composting ecosystem and should be appreciated, not feared. Do not attempt to spray or otherwise kill these beneficial critters.

  • Consider placing a tarp or lid over your pile to prevent water logging during wet periods, conserve moisture during dry periods, and prevent nutrient leaching.

  • Watch our composting videos for more information. 



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