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Lawn Care & Maintenance in Portland, OR

Quick answer

Portland lawns are cool-season grasses, usually perennial ryegrass and fine fescue mixes. They grow most in spring and fall, which is when to fertilize, aerate and overseed. Moss is the most common complaint, and lasting fixes address shade, drainage, compaction and thin turf. Companies applying pesticides for hire need Oregon Department of Agriculture licenses.

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Lawn care in Portland is mostly about managing the wet season and deciding what to do about the dry one. Portland lawns are cool-season grasses that grow fastest in spring and fall, stay green through the mild, rainy winter, and slow down or go dormant in a dry summer. The common problems here are moss, shade, compaction and soggy soil, not heat stress.

What grows in Portland lawns

  • Perennial ryegrass: fine-textured and dark green, and the usual choice for sunny western Oregon lawns. It needs regular mowing, feeding and summer water to look its best.
  • Fine fescues: handle shade and low fertility well and can persist with little irrigation, though they may go dormant in summer.
  • Tall fescue: a lower-input, more drought-tolerant option for sunny lawns.
  • Bentgrass: often creeps into lawns that aren't fertilized regularly, because it thrives in low-fertility conditions.

Oregon State University Extension recommends a perennial ryegrass and fine fescue mix for sunny lawns west of the Cascades, and a fine fescue dominated mix for shade.

A seasonal rhythm

  • Spring: the main growth flush. Mowing every week is common, and spring is one of the two main windows for fertilizing and overseeding.
  • Summer: either irrigate regularly or let the lawn go tan and dormant. OSU notes that unwatered lawns usually recover when fall rains return.
  • Fall: the best window for core aeration, overseeding and repairing thin areas, and a second key time for feeding.
  • Winter: stay off soggy turf, which compacts easily, and keep leaves from smothering the grass.

Mowing heights

OSU Extension's Practical Lawn Care for Western Oregon lists maximum mowing heights by grass: about 2 inches for perennial ryegrass, 2.5 to 3 inches for fine fescues, and 3 to 4 inches for tall fescue. Whatever the grass, remove no more than about a third of the blade at a time, and leave clippings on the lawn to return nutrients.

Moss is a symptom

Moss thrives in shade, wet and compacted soil, acidic conditions and thin turf, which describes a lot of Portland yards in January. Moss killer alone usually brings the moss right back. Lasting fixes deal with the cause: more light through careful pruning, better drainage, aeration, a soil test to check pH and nutrients, and overseeding. In deep shade, beds or groundcover may beat grass.

Pesticide licensing

Mowing and routine yard maintenance are not regulated by the state. But in Oregon, a business that applies pesticides, including herbicides and moss or weed products, on other people's property generally needs a commercial pesticide operator license from the Oregon Department of Agriculture, and the people doing the application need a commercial applicator license. If your program includes weed, moss or insect control, ask for both.

What to ask before signing up

  • Is the program built for my grass, sun and soil test, or is it the same for every yard?
  • How do you handle moss, and what are you doing about its cause?
  • Do you offer fall aeration and overseeding?
  • How much notice do you give before applications, and when is it safe for kids and pets?

For more on choosing grass and beating moss, read our Portland lawn guide, or request a lawn care company.

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How a sprinkler zone waters a lawn. Press the buttons to run each step and see what happens inside. Made with Colorfigures ·
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Frequently asked questions

What is the best grass for a Portland lawn?

Oregon State University Extension recommends a perennial ryegrass and fine fescue mix for sunny western Oregon lawns, and a mix dominated by fine fescue for shade. Tall fescue is a lower-input option for sunny sites.

Why is my lawn full of moss every winter?

Moss thrives in shade, wet and compacted soil, and thin turf, all common in Portland winters. Killing it without fixing light, drainage and turf density usually means it returns.

Is it OK to let my lawn go brown in summer?

Yes. OSU Extension notes that unwatered lawns in western Oregon go dormant and usually recover when fall rains return. A deep soaking in early September can help it recover sooner.

Sources and further reading

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