Are you tired of your lawn looking ragged? To maintain a lawn that will impress your neighbors and friends, it needs to be renovated every five years or so to keep the grass healthy and competitive against the ever-present barrage of weeds that will encroach on your turf. Learn practical tips for lawn renovation and lawn care to keep your yard looking great.
Get clear on your grass goals to know what your lawn will need
Maintaining a healthy lawn requires time and energy. The smaller the lawn, the easier it will be to maintain. Think about your lifestyle and how much lawn you really need for recreation and aesthetics. Consider replacing some or all of your lawn with flowers, natives, edibles or pervious hardscape, which require less care than lawn. Also, get clear on how you want to maintain your lawn. You can let a lawn go brown in summer and it will green up with fall rains, but it will be less competitive against the weeds and will require renovation more frequently. A four-season or manicured lawn will take more time and resources to maintain in terms of mowing, watering, and fertilizing, but will not need to be renovated as frequently.
Renovate lawn in the spring or fall for best results
The optimum temperature range for cool-season turf, the dominate species within the PNW, is 60 to 75 F. During these months you get the combined effect of optimum temperatures are increased plant available water, because of the seasonal rains and reduced ET rates. Some great dates for lawn renovations are Memorial Day and Labor Day. Don't seed after October 15, as germination will be poor and your stand of grass will not be able to out-compete the weeds. The best defense against weeds is to grow a vigorous stand of turf, so as bare spots and thin areas developed over time inter-seed these areas in the spring and fall.
Remove unwanted weeds first
If dandelions or other broadleaf plants exist on the lawn area that you want to renovate, start by removing these weeds. If you plan to do this by hand, pre-water the area to loosen up the soil to make it easier to pull the weeds by hand. A hori-hori gardening knife can make this chore relatively easy. If the weeds are very abundant, consider using a broad-spectrum herbicide to kill all of the grass and weeds several weeks in advance of soil preparation. The weeds in the Pacific Northwest are most susceptible to herbicides during the fall months; therefore, spraying and then seeding in the fall is a great two punch combination for future weed prevention.
Create the right soil conditions
Turf grass needs the right soil conditions in order to prosper. Consider getting a soil test for pH and/or add lime to help neutralize acidic soil conditions. Grass in lawns grows best when the pH is between 6 -7. Native soils of the Willamette Valley are typically more acidic and require lime to grow healthy turf. A "basic soil test" will not only provide a lime recommendation, but is will also tell you if you have any other nutrient deficiency and provide recommendations for resolving these issues.
Expose the soil surface
Mow the grass short. Rent a power dethatcher or use a hand-dethatching rake to expose soil for seeding and to remove moss and weeds. Go over the soil as many times as needed to reach the soil to ensure good seed-soil contact. If soil is severely compacted, rent a core aerifier machine after dethatching and go over the lawn several times. Then use the dethatching machine one more time to break up the soil plugs left on the soil surface.
Choose the right mixture of grasses for West of the Cascades
Seed for lawns typically comes in mixes with different grass species based on the intended use of the lawn. Most mixes for the Willamette Valley will have about 70-80% perennial rye and 20-30% fine fescue. For shadier areas, look for seed mixtures that are largely fine fescue. If you have a sunny lawn that is irrigated choose mixtures high in perennial rye and if un-irrigated look for turf-type tall fescue.
Ecolawns are grown with grass and low-growing, drought-tolerant, flowering plants such as clovers, yarrow, and English daisy. The added diversity of plants reduces water and maintenance needs and looks beautiful. Look for "eco-lawn" seed mixes at the nursery.
Apply seed liberally
Follow the instructions on the seed package in terms of application rate. Buy a seed spreader to ensure a good spread of seed across the renovated area. Divide the seed needed for the whole area in half and disperse the seed moving in two directions to ensure adequate coverage. Purchase an extra bag of seed and inter-seed weak areas 3 to 4 weeks after the initial seeding. Remember that grass seed is relatively in expensive and you want to error on the side of over application to ensure a good stand that will compete against the weeds!
Apply fertilizer just before or after seeding; look for fertilizer with low phosphorous (for example one with "20-5-10" on the label, indicating 20% Nitrogen, 5% Phosphorous, and 10% Potassium). Apply the fertilizer at a rate of 1.0 lbs. N per 1,000 ft2 (if you buy a fertilizer designed for turf the bag will provide direction to achieve this rate). Reapply fertilizer 4-6 weeks after seeding. These first two applications of fertilizer are the most important for lawn to get off to a good start by providing food for proper establishment before winter. If you use organic fertilizers substantially more product will need to be applied to achieve nutrient because of the low nutrient levels these products inherently have.
Water frequently until germination occurs and thereafter
If you choice to renovate you lawn in the spring, rather than the fall, consistently moist soil is key for good seed germination and establishment. If possible, water four times per day until soil starts to glisten until the seeds germinate. This step should be easy if you have a built-in watering system with a timer. If not, purchase a programmable timer to put on your hose bib and use an oscillating sprinkler such that you can water the whole area without having to move it around. Keep the soil moist, but not waterlogged. As the seasons transition from spring to summer frequent irrigation is required to sustain the newly established lawn for the first year, to avoid this renovate turf in the fall. Mow your renovated lawn as soon as possible at a 2 inch height. The emerging turf is well adapted to frequent mowing, while newly established broadleaf weeds are not. Mowing early during establishment will also promote lateral growth or tillering, which translates to increased density during this early developmental stage.
Find more information
Contact OSU trained volunteers for questions lawn renovation and other gardening questions: metromastergardeners.org/index.php