Garden Variety: Getting the lawn in shape

Whether you want a perfectly sculpted lawn or just enough grass to prevent erosion and keep down the weeds, the next four to six weeks is the most important time of year for lawn care.

Even a little bit of seed and fertilizer make a big difference, and your neighbor who waits until next spring to fertilize will wonder why your lawn greens up faster, is thicker and looks better going into the summer.

If you have the time and the means, go for the full renovation. Renovation can mean getting rid of what is there altogether or simply improving what is there (think remodeling). The basic steps are to dethatch/verticut, core aerate, overseed and fertilize. At the bare minimum, overseed and fertilize.

The next four to six weeks are a critical time to get your lawn prepared for next spring, from basic seeding and fertilization to giving it a full renovation.

The only exception to the fall lawn care rule is for lawns with warm-season grasses, including zoysiagrass, buffalograss and bermudagrass. Because these grasses are at their best in the hottest months of summer, June and July are a better time for maintenance.

Dethatching/verticutting

Dethatching requires a machine with vertical blades to pull the vegetative layer out from the just below the soil surface.

Dethatching allows water and air to move more readily into the root zone and breaks up the hard soil surface, giving seed a chance to make good contact with the soil and root in more easily.

Machines range in size from walk-behind to tractor attachments and can be rented from equipment rental services or some hardware stores. You may also wish to hire a lawn care company to complete this task.

After dethatching, rake up the material that is pulled out of the lawn and compost it.

Core aerating

Core aerating means to remove cores of soil to aerate the lawn.

Core aerators have a large roller with hollow spikes that pull cylindrical cores of soil up and drop them back on the soil surface. The holes created by the aerator alleviate compaction and allow water and air to reach plant roots.

A core aerator should be run over the lawn in two different directions, perpendicular to each other for best results. Core aerators also range in size and can be rented or hired.

Overseeding

You get what you pay for with grass seed.

Look for the label (on every bag of grass seed sold in Kansas) that shows the seed makeup, percentage of weed seed and seed origin. Seed from the Midwest will perform better than seed from regions with vastly different climates than ours.

Also, look for the lowest percentage of weed seed possible, unless you really want to plant more weeds in your lawn. Turf-type tall fescues provide the best drought, heat and disease resistance in the Lawrence area. Blends of three to four types of turf-type tall fescue provide the best results.

Use a verticutter to break up the soil surface, or a rake or similar tool. Throwing grass seed down on hard, dry soil is just feeding the birds.

Fertilizer

Whether using organic or conventional fertilizer, use a product that is high in nitrogen and has low levels of phosphorus and potassium.

This is represented by the three numbers on the bag, listed as 27-3-3 or 33-1-1 (nitrogen-phosphorus-potassium). Use at the labeled rate.

— Jennifer Smith is a former horticulture extension agent for K-State Research and Extension and horticulturist for Lawrence Parks and Recreation. She is the host of “The Garden Show” and has been a gardener since childhood. Send your gardening questions and feedback to Lawrence Living@ljworld.com.