In my opinion (that, admittedly, is a bit biased), you can’t currently find higher quality lawn seed mixes than my "Terry's Best" mixes for sunny and shady lawns!
Let me explain why.
For sunny lawn conditions (i.e., lawns receiving more than four hours of direct sun each day), turfgrass specialists at universities throughout the United States have long recommended that seed mixes should contain a minimum of two, and preferably three to five Kentucky bluegrass varieties along with at least two fine leaf fescue varieties (chewings, creeping red and/or hard). Also, only a small percentage of perennial ryegrass (no more than ten to fifteen percent by weight) should be included as a nurse crop to stabilize bare ground until the Kentucky bluegrass and fine fescue seed germinates two to three weeks after sowing.
Conversely, it's recommend that lawns receiving less than four hours of direct sunlight each day be seeded with a mix contain a minimum of two, and preferably three or more fine leaf fescue varieties, one or more shade-tolerant Kentucky bluegrass varieties and, again, just a small percentage of perennial ryegrass as a nurse crop.
The logic behind a greater number of varieties in a seed mix is better performance through genetic diversity.
If, for example, one or two Kentucky bluegrass or fine leaf fescue varieties in a seed mix turn out not to be well-adapted to the conditions of a given lawn, the others will fill in any gaps - instead of leaving an opening for weed seed to germinate.
Meanwhile, perennial ryegrass seed often germinates within a week of sowing and the resulting seedlings grow rapidly. If there's more than ten to fifteen percent perennial ryegrass seed in a mix by weight, the seedlings can smother the slow-growing Kentucky bluegrass and fine leaf fescue seedlings. This can result in a lawn that consists almost entirely of a single perennial ryegrass variety a year later.
Not exactly a very genetically diverse lawn, right?
So, how do typical "premium" lawn seed mixes from one of the most well-known lawn product companies compare to research-based recommendations?
"Premium" Big Name Lawn Seed Mix Example
Given the above recommendations, what's in a relatively recently (2005) packaged bag of, let's say, Scotts "Pure Premium" High Performance Grass Seed Mixture for sunny lawns, at left?
Well, there are two varieties, of Kentucky bluegrass, `Abbey' and `Victa.' However, there are no fine leaf fescues. And, almost forty percent of the mix, by weight, is perennial ryegrass (the variety `Summerset').
So, what's the chance that one or the other of the Kentucky bluegrass varieties will be well-adapted to the conditions posed by every single lawn on which the mix is sown? Also, because there are no shade-tolerant fine leaf fescues in the mix, what happens over time in shady spots where this mix is sown? And, are either of the questions above even pertinent as it's possible that the high percentage of perennial ryegrass in the mix might result in the almost complete loss of both Kentucky bluegrass varieties over time?
What about Scotts "Pure Premium" High Performance Grass Seed Mixture for shady lawns, at right?
I'm immediately concerned as there's only a single shade-tolerant fine leaf fescue variety, `Fenway' creeping red fescue. In lawns where this variety doesn't perform well, will there be significant thinning and subsequent weed infestations? And, again, with such a high percentage of perennial ryegrass in the mix, will the seedlings of this fast-growing species overwhelm the fine leaf fescue and Kentucky bluegrass seedlings within a matter of months after seeding?
"Terry's Best" Lawn Seed Mixes
In a nutshell, I've researched and designed "Terry's Best" lawn seed mixes to meet, or exceed university research-based lawn seed mix diversity recommendations in cooperation with the Seed Super Store in Buffalo, New York.
"Terry's Best" Sunny Lawn mix, at left, contains four Kentucky bluegrass varieties, two fine leaf fescue varieties and only ten percent perennial ryegrass.
Meanwhile, "Terry's Best" Shady Lawn mix, below right, contains three shade-tolerant Kentucky bluegrass varieties, three fine leaf fescue varieties and, again, only ten percent perennial ryegrass.
All of the varieties in these mixes have been selected for their ability to develop an attractive lawn under moderately low maintenance, and are among the top performers in the National Turfgrass Evaluation Program.
"Terry's Best" Lawn Seed Mix Limitations
Despite my confidence in the quality of "Terry's Best" lawn seed mixes, they're not "miracle" grasses! They will not grow into the most attractive lawn in your neighborhood if you . . . . ,
For More Information
You can download and print product information sheets for both seed mixes (roughly 32KB .pdf files) by clicking on the links at the top of the column along the right side of this page.