Spring is not the ideal time to overseed a cool season bluegrass or fescue lawn. The period between spring weeds and establishment of grass before summer conditions is short. But for those faced with bare patches spring seeding may be the fix.
The best time to spring seed is mid-March through early April. The steps for spring seeding mimic those of fall — it starts with soil prep. The recommended method is verticutting. A verticut slices grooves in the soil and allows good seed and soil contact for germination.
Simply scattering the seed on the ground usually results in a poor stand and a waste of time and money. Very small patches can be roughed up with a garden rake.
Once the soil is prepared, the seed can be broadcast. Then the fun of overseeding begins as the soil surface must be kept moist through germination and into early establishment. This means light, frequent water applications based on weather patterns.
The good news is that in the spring, temperatures are cooler and skies are more overcast, and, ideally, rainy days are likely to reduce the watering demands of a hot September day.
The length of time it takes for the grass seed to germinate depends on the temperatures. Expect at least two to three weeks or more for emergence.
Once the seed is up, reduce the frequency of watering. Water when the seedling grass shows signs of stress, such as wilting or turning a bluish cast.
Spring-seeded turf has a limited root system. Do not attempt spring seeding unless you are committed to watering during the summer. Without regular watering, you will be right back where you started and out your time and money.
Spring-seeded turf will need a little more fertilizer to get it up and growing. At seeding apply a starter type fertilizer. Make another application about four weeks after germination.
This time use a high nitrogen source of fertilizer such as 30-0-0, and if possible,a formulation that contains a percentage of slow-release nutrients. This helps spread the feeding and reduces summer stress by not being under such a lush application of nitrogen.
One of the historic problems with spring seeding has been excessive crabgrass germination. Thin turf and disturbed soil result in a bumper crop. Fortunately, crabgrass control products can help us overcome this problem.
The product Dithiopyr or Dimension is recommended for spring seeding as it can be applied later into the season and still provide good control. This product actually works as a pr-eemergent and on seedling crabgrass which has already germinated. In most seasons it can be applied in early to mid-May and still provide excellent season-long control.
Now is the time to decide whether to seed this spring or just wait until fall. No matter what you decide, planning will lead to success as well as knowing the proper steps.