Seed Germination Slow to Happen

Sports fields that were renovated and seeded this past spring and summer may have not performed very well this fall playing season. There have been several instances where field managers tried to establish seed and had the irrigation and other resources available but still the seed did not grown in very well.

There are a number of reasons that seed may not have done well this past summer:

Pre-emergent herbicides were used during the spring to prevent crabgrass and other weeds. If a weed control product was applied to the field, there is typically a period where any seed that is applied will also not germinate (i.e. seed is killed by the herbicide). Some seeding re-entry periods may be up to 12 weeks long. Two chemicals that can be used at the same time as seeding that will not negatively affect seed germination are Tenacity (mesotrione) and Siduron (Tupersan)

There were very high temperatures, both day and night, starting much earlier in the spring than usual. The late spring and summer of 2012 brought a record amount of daytime temperatures above 90F (and several above 100F) and equally important, many night-time temperatures over 70F, especially in June and July. Cool season grasses have optimal temperatures at which they will germinate (see below). Outside of those optimum ranges, seed germination can be delayed.

The optimum temperatures for seed germination* of turfgrasses as established by the association of official seed analysis

Kentucky bluegrass (Poa pratensis): 59-86 F
Perennial ryegrass (Lolium perenne ): 68-86 F
Tall fescue (Lolium arundinaceum, Schedonorus phoenix, Festuca arundinacea ): 68-86 F

*Temperatures separated by a dash indicate an alternation of temperature; the first numeral is for approx. 16 hr. and the second for approx 8 hr.

If the grass seed had germinated the young seedlings would have also been affected by the high temperatures. During heat stress periods, cool-season grasses are subject to a process called "photorespiration", whereby the grass plant actually uses more energy than it manufactures. This results in poor shoot and root growth. Young turf plants with immature root systems going into the summer stress period will typically not be able to recover quickly enough by mid-August to host fall sports.

Lack of an adequate syringing program during the grow-in, followed by insufficient irrigation to replenish at least 80-90% of water lost through ET. For more details on syringing, click here. 2012 brought record drought to Ohio, with many areas of the state carrying as much as 11-inches rainfall deficit by the end of the summer. Water conservation by watering very early in the morning and using covers or topdressing materials to conserve moisture during seeding helps. In addition there are cultural practices to minimize plant stress during drought, like raising mowing heights and avoiding stressful practices like verticutting and scheduling games on drought-stricken fields.

Moving forward, there are a couple of options:

(1) Use sod to repair high traffic areas like soccer or lacrosse goal mouths, sidelines and field centers between hash marks. Sod can be put down anytime as long as the soil is not frozen and it will be play-ready by spring 2013. Sod also offers an opportunity to get 100% Kentucky bluegrass on the field. There are many sod growers in Ohio that can be found on The Ohio Sod Producers Website.

(2) Put seed out as "dormant seed" in winter (December-March) to get germination as quickly as possible in 2013. The seed will not germinate until conditions are favorable next spring but it will be "in place" and ready to germinate. Seed mortality rate is typically higher than a conventional spring seeding so seed rates should be around 30% higher than normal.

(3) Do a conventional spring seeding as soon as conditions are favorable, coupled with an application of Tenacity or Siduron to keep competition from weeds to a minimum. Perform sound cultural practices (regular mowing, soil cultivation, adequate irrigation and fertilizer) to promote plant maturity before the summer stress period. Also, a growth blanket offers great benefits when trying to establish turf quickly. A growth blanket conserves heat and moisture, as well as keeping people off during the renovation process.


Turf n Tacos!

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