Lake Whatcom-friendly Lawns and Gardens

Lake Whatcom Guidelines

Since Lake Whatcom serves as our drinking water source, the City has adopted specific guidelines for materials and practices in the Lake Whatcom watershed. The City conducted testing of various landscaping products from multiple vendors to learn about phosphorus and fecal coliform bacteria content. In addition, the City sought the advice of professionals in the landscape field regarding best available soil amendments. This information was used to develop the guidelines below. To learn more and receive financial and technical assistance, participate in our Lake Whatcom Homeowner Incentive Program.

Mulch recommendations vary slightly in the watershed to protect the lake from nutrient (phosphorus) runoff:

  • For lawns, collect your grass clippings and dispose of them in a curbside yard waste bin.
  • For landscape beds and gardens, use hog fuel mulch. This material supports helpful soil microbes and is lower in soluble reactive phosphorous.
  • For building healthy soil, use only mulch, topsoil and compost products approved for watershed use by the City of Bellingham. These low-phosphorus products are the best option for protection of lake water quality.

Avoid use of fertilizers, pesticides, and herbicides. Phosphorus-containing fertilizers, mulches and soil amendments are prohibited within the Lake Whatcom watershed. Learn about ways to manage weeds naturally.

  • If possible, replace lawn area with native landscaping to reduce nutrient pollution and yard maintenance.
  • For remaining lawns, mow periodically with the mower set to 2” or higher for most turf types. Higher grass absorbs more water and improves capture of grass clippings.
  • If possible, collect grass clippings and dispose offsite using services listed below.
  • If offsite disposal is not an option, use a mulching mower, being careful to mow at a high setting and during dry periods. Excess phosphorus from mulched clippings can end up in the lake where it feeds algae blooms, harming water quality and fish.
  • After mowing, sweep lawn trimmings away from the street and sidewalk. Lawn trimmings left on pavement can wash into storm drains, clogging the stormwater system and adding excess nutrients to our waterways.

It might not seem intuitive, but yard waste such as leaves and grass clippings can cause pollution. You are required to manage it properly. Placing it near ditches, roads, and water bodies is illegal and causes pollution.

Yard waste piled near ditches, roads, or water can:

  • Cause flooding and cost money by plugging storm drains and culverts.
  • Degrade water quality and harm fish and wildlife because pollution from excess nutrients causes oxygen depletion in the lake.
  • Harm native habitat and vegetation by spreading invasive species.

Best choices for yard waste disposal:

A note about composting at home:
A well-managed at-home compost pile can be a good option for disposing of yard waste, but Lake Whatcom is sensitive to nutrients from compost piles and compost use.

If you live in the Lake Whatcom watershed, the best option for water quality protection is to dispose of yard waste offsite using one of the options listed above. If you do practice home composting, please follow best practices for water quality protection.

Place hardwood chips, arborist chips, or hog-fuel mulch over soil to reduce erosion. Use a barrier such as bricks or wood to contain soil in the garden.

  • Go Gold and let your grass go dormant during the summer.
  • Plant native plants to reduce the need for water.
  • Avoid runoff during watering.
  • Explore more water conservation methods.

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