Guide to creating a cool season blend

[Fronta1]

The following is a seeding guide for cool season grasses

Fine fescues are only recommended for shade in the lower 48, as their delicate blades are vulnerable to the strength of the full summer sun.

As for tttf,kbg, and prg,

It is not recommended to use more than 20% prg in any blend, as the vigor of prg will dominate other grasses. It's also thought that it releases a chemical that actually inhibits the growth of kbg. But studies show that even when blended with tttf, the prg came to dominate the lawn when more than this approximate proportion was used.

It is also suggested to sow them in stages in order to ensure desired final ratio. Always sow kbg first. Sow tttf at least one, preferably two weeks later. Prg should be sown three weeks after kbg, and at least two weeks after tttf.

Different varieties have different weights. Average recommended seeding rates are 2-3 (for simplicity sake we will use 3) lbs per 1k sq ft for kbg, 6-8 (7) lbs per 1k sq ft for prg, and 8-10 (9) lbs per sq ft for kbg.

In order to determine how much of each variety you need, the math is as follows

Multiply your total sq ft by the percentages you want for each variety. For example if you are seeding 10k sq ft and you want 50/50 tttf/kbg, the math is: 10k(.50)=5k sq ft. If you are seeding 12k sq ft and you want 50% tttf, 25% lbs, and 25% prg, three math is: 12(.50)=6k, 12(.25)=3k.

Now take your resulting sq ft and multiply it by each variety seeding rate. In the first example, where we used 50/50 tttf and kbg for 10k sq ft, the math is 5k(seeding rate of tttf, or 9)=45. So you need 45 lbs of tttf. For the kbg, it's 5k(seeding rate of kbg, 3)=15. So to sow 10k sq ft with a50/50 mix of tttf and big you need 45 lbs of tttf and 15 lbs of kbg.

For example 2 the results are: 6k(9)=54 lbs of tttf, 3k(3)=9 lbs kbg, and 3k(7)=21 lbs prg.

Be aware that blended lawns ratios will change over time. As prg and tttf are bunch grasses, they will thin with age, while kbg will spread. So if if kbg is included in the mix, you may choose a smaller percentage in order to achieve your desired ratio over the course of a few years. Also remember that any blend that contains kbg will eventually be dominated by kbg if given proper care and conditions, unless of course prg is included, in which case kbg may not spread as rapidly or at all depending on the initial amount of each

And finally, remember that including prg in your mix will have an effect on your overall blend as well. It will out compete other grasses for resources, which means it will reach its full potential, while tttf and kbg will be inhibited. And again, studies suggest that prg will not only out compete but even stop kbg from trying, so a mix that includes them both may not ultimately result in a kbg dominated lawn to the extent that the prg remains.

[ezael]

Great post, just saw one typo. Recommends 8-10 lbs kbg per 1000. Ment to be fescue I believe, just wanted to help prevent confusion.

+1

[Fronta1]

Great post, just saw one typo. Recommends 8-10 lbs kbg per 1000. Ment to be fescue I believe, just wanted to help prevent confusion.

+1

Doh! If I could edit original post I would. But yeah, you're right, that's the seeding rate of tttf. Kbg is 2-3 lbs per k sq ft.

[bpgreen]

One other clarification is that typically, when we discuss blends here, it means more than one cultivar of the same species (for example:midnight, bewitched, prosperity). If we're talking about different species, we generally use the term mix.

[timingchainslipped]

nicely written guide, but the seeding rates seem to contradict this post:

viewtopic.php?forum_uri=northern&t=11054&start=

i'm very interested in the outcome, given that i'm planning a mixed reno this fall.

[Fronta1]

nicely written guide, but the seeding rates seem to contradict this post:

viewtopic.php?forum_uri=northern&t=11054&start=

i'm very interested in the outcome, given that i'm planning a mixed reno this fall.

Thank you. Yeah I've seen that post. He uses seeding rate but I don't know why you wouldn't use the recommended seeding rate. The 90:10 thing is not accurate either, that is a ratio sod farmers use because kbg is expensive but they need it to hold sod together. 90:10 might give you 50/50 after a few years if the kbg gets a chance to establish but 75:25 will give you 50/50 off the bat.

[Fronta1]

It's really really really really simple. Just act like you are seeding x# of different yards, each with one variety. So you just divide the total sq ft into the percentages of the mix you want and multiply each of those by the seeding rate for each variety and divide by a thousand and that's how many lbs you need of that variety. That's it, done.

[andy10917]

Fronta, is any of this guide stuff that you have tested, or is it Google-fu and math formulas? Looking back to your early posts, you don't seem to indicate that you have a ton of experience with renovations. There are spots where you're questioning why someone didn't line up with your math/rates, but I see no proof that your rates, etc are tested better. And folks that have lots of experience don't tend to jump in with "it's really, really, really easy" much - few things are as easy as they seem on the surface.

[Fronta1]

If you don't agree that's fine. I'm quite confident I'm right.

[andy10917]

That doesn't answer the question -- is this all tested?

[Fronta1]

That doesn't answer the question -- is this all tested?

I'm not going to say it has, because it does not make a difference.

It's a logical, mathematical, black and white type of thing for folks like me who like to do things that way.

I'm totally cool with you challenging my conclusion, I would love to see why you think it isn't sound.

[GeorgeH]

Fine fescues are only recommended for shade in the lower 48, as their delicate blades are vulnerable to the strength of the full summer sun.

Pretty broad brush. FF in my geo grows very well, is my preferred and dominant species and does great even during the long, warm to hot summer days..

[STL]

90:10 might give you 50/50 after a few years if the kbg gets a chance to establish but 75:25 will give you 50/50 off the bat.

Just curious, how do you know this? Is that what you've seen over the years in the lawns you've renovated? Why wouldn't 80/20 or 85/15 yield a 50/50 tttf/kbg split 'off the bat'?

Also, what factors contribute to or prevent one of the species from shifting the ratio over time? Should that be accounted for or no?

[andy10917]

I'm not going to say it has, because it does not make a difference.

It's a logical, mathematical, black and white type of thing for folks like me who like to do things that way.

I'm totally cool with you challenging my conclusion, I would love to see why you think it isn't sound.

I don't have a problem with your statements as opinions, but your questioning of why others don't just knuckle under to your methods since they are clearly correct rubs me wrong. Real science builds theories like your's, and then tests them through empirical testing.

empirical adj. Relying on or derived from observation or experiment. Verifiable or provable by means of observation or experiment.

So, it DOES make a difference. The fact that PRG will overtake KBG was not found by "logic" or theory - it was found by direct observation.

I'd personally advise less-experienced members to take the "Guide" above with several grains of salt, as while it is stated emphatically and represented as Fact, much of this is Opinion that lacks testing and/or a lot of experience with Renovations.

[Owlnsr]

All grass (and plants, even) are alleopathic. PRG just happens to more effective in its production and emission of biochemicals that favor it's survival over the competition. This is one reason why having a high percentage of PRG (>20%) in a seed mix can lead to PRG dominating the lawn. That being said, weeds, grasses and other plant types can still invade a pure PRG stand; in other words, the biochemicals alone do not result in PRG domination.

[andy10917]

All grass (and plants, even) are alleopathic.

Do not agree.

the biochemicals alone do not result in PRG domination.

Agree.

[g-man]

^ I think there are some missing posts. I can't find the post you quoted Andy

[andy10917]

Nah. Stupid failed cut-and-paste from a completely different post (last night!). It's corrected.

[PSU4ME]

^ I think there are some missing posts. I can't find the post you quoted Andy

Ha I was looking for the soil test post myself lol.