First step in rehabbing troubled turf is to identify the cause of damaged or thinned turf. One or more of these conditions may exist.
Once the cause of turf decline is identified, select a turf improvement program that will best upgrade the turf by taking into consideration the existing conditions and the desired turf quality.
Leaf shredding on ryegrass due to a dull or poorly adjusted blade. Before ryegrass, shredding was a minor problem.
Perennial ryegrass looks good when mowed between 1.5 and 2.5 inches. It can tolerate mowing as low as .75”, but is rapidly invaded and dominated by other grasses such as bentgrass and annual bluegrass. Golf course fairways planted with ryegrass and mowed at 0.5” will quickly convert to annual bluegrass.
Mowing an erect growing grass low drastically reduces the leaf surface area of individual shoots.
Catch Can Test
When nitrogen is applied in the ammonium form during late fall or early winter, it stays in the ammonium form because temperatures are too cold for nitrification to occur. In the mild winter areas west of the Cascade Mountains, the result is dark green turf all winter because of the nitrogen effect on chlorophyll content and the fact that growth is slow due to cold temperatures so mowing doesn’t remove much nitrogen. Grass growing under low nitrogen in fall will go off color rapidly in fall and leave you with a brown lawn all winter long. This is apparent in the unfertilized plot in this trial.
It is hard to get good seed to soil contact with no till renovation techniques. One way to get better uniformity and insure rapid germination is to apply a mulch. I always try to mulch renovated sites.
If you have a good grade but want to put in a different grass, a complete renovation is sometimes the best way to go. If you just want to bolster the existing turf, you can use a partial renovation.
If you do everything right, it doesn’t matter much what technique you use for planting a new lawn or renovating an old one.
Most grasses are very responsive to nitrogen. When nitrogen fertilizer is applied the grass soon develops dark green color as chlorophyll content increases. Shoot growth rate increases and there may be an increase in the number of green leaves per shoot. Over all turf looks dense and green. Provided water is not limiting vertical growth rate increases, which means you have to mow regularly to keep the lawn under control.
“ Rehabbing Troubled Lawns” Rob Golembiewski, Ph.D. OSU Oregon State University