I know winterizer timing is an oft-discussed issue here. First, let me make sure my understanding is correct. Based on previous posts, I got this info regarding cool-season grass growth:

60-75F Optimum temperature for shoot growth.
50-65F Optimum temperature for root growth.
40F Shoot growth ceases.
33F Root growth ceases.
20F Low temperature kill possible if temperature subsequently drops rapidly below 20F

These temperatures are all 4-inch depth soil temps. As I understand it, you want to time winterizer application, as best you can, for the time when root growth is still occurring but shoot growth has ceased. That means when soil temps are between 33F and 40F.

Well, what if you live in an area where soil temps never get down to 33? Does that mean that roots are actually growing, developing, and storing energy throughout the winter? If that's the case, does one winterizer application make sense? If so, when would it be? If not, does this change the game completely?

This is relevant for everyone growing cool season grasses in the transition zone. I am working on getting data for my immediate area, but the nearest station on the SCAN site has data going back to 2003. What I found in analyzing this data is that soil temperatures only dip below 40F for 20-25 days each winter, and that they have never dropped below 33F in the 8-year period. That means shoot growth only stops for a short time, while root growth apparently never completely ceases in the winter (though it does in the summer months with 35-40 days above 77F soil temps). For what it's worth, the first date below 40F has varied between the second week of December and the middle of January.

So how does one proceed with this knowledge? Do I plan for a quick-shot winterizer in December like everyone else does, despite the fact that the roots are going to keep growing anyway? Do I slowly feed throughout the winter? Can I use organics instead of synthetics, or will the microherd sleep even though the roots won't?

Before I am accused of overthinking (a fair accusation), this question is as much an academic one as a best practices one. My local Ag Extension has tons of publications, but as far as I can tell this particular line of inquiry has not been addressed. I have found sources in warm areas that suggest fertilizing TTTF in early December and late February, but I think they considered that a winterizer app and an early spring app rather than winter feedings.

Any thoughts?

Following. Trying to figure out the same thing for my TTTF schedule in Atlanta, GA.

There may be additional factors other than soil temperature that determine both top growth and root growth. The one that comes to mind is the amount of daylight. There's probably a soil temp/amount of day light ratio that may cause dormancy even if the temps are in the zone mentioned. Just my 2 cents.

Go when top growth stops, which for you is probably sometime in December. The roots may keep growing and the grass may stay green, but that's OK. My grass stays green in Pennsylvania, although I doubt the roots grow much if at all in February.

What you'll encourage is deeper root growth, which is a good thing (and the same reason I fertilize heavily all fall once temperatures drop into the root-growth range). Never going dormant, the grass doesn't really require winterization (which is to store carbs when the top can't photosynthesize and survive the winter that way). But feeding still encourages that root growth cycle to continue.

December/February sounds kind of wrong; I'd actually do December/April (when your spring is already well underway, about the equivalent date to our Memorial Day). You don't want to force growth in early spring as it'll end up costing you summer performance.

Awesome. Was hoping you'd chime in.

Thanks Morph

shawnj wrote:There may be additional factors other than soil temperature that determine both top growth and root growth. The one that comes to mind is the amount of daylight. There's probably a soil temp/amount of day light ratio that may cause dormancy even if the temps are in the zone mentioned. Just my 2 cents.

I had to think about this. It does seem to have some influence, but nothing particularly strong. My lawn stays green, but growth stops in late November, already well after the onset of solar winter (which starts November 7th, the three months of the year with the least light). It gets closest to dormancy in February when our weather is coldest, but that's already at the end of solar winter or the beginning of solar spring (February 7th or so on average).

Growth doesn't resume until late March (astronomical spring, halfway through solar spring), and doesn't stop until late November (astronomical fall, solar winter), so the correlation doesn't seem to be that good.

Temperatures seem to be the driving factor.

MorpheusPA wrote:Go when top growth stops, which for you is probably sometime in December. The roots may keep growing and the grass may stay green, but that's OK. My grass stays green in Pennsylvania, although I doubt the roots grow much if at all in February.

What you'll encourage is deeper root growth, which is a good thing (and the same reason I fertilize heavily all fall once temperatures drop into the root-growth range). Never going dormant, the grass doesn't really require winterization (which is to store carbs when the top can't photosynthesize and survive the winter that way). But feeding still encourages that root growth cycle to continue.

December/February sounds kind of wrong; I'd actually do December/April (when your spring is already well underway, about the equivalent date to our Memorial Day). You don't want to force growth in early spring as it'll end up costing you summer performance.

I think that's probably the wise plan in general (winterize in December). Even if the roots continue to grow and take in nutrients, you'd have to think it would be happening slowly . . . and they've already got a stock of organics to draw from. I put down SBM about a week ago.

As for your last comment though, I don't think I'm going to fertilize in the Spring at all. From reading others' experience and some research, I think the heat of the summers here can really cause trouble when you encourage a lot of Spring topgrowth. I haven't decided 100% but I'm leaning toward fall feeding only (well, organics starting in late summer).

You can do that if you like, or use organics in spring (which don't cause the same issues as synthetics do as the nitrogen never pours in).

If you feed well during fall, there's no real reason for a spring feeding, although most lawns around here would really like some kind of brunch about Memorial Day. That can be skipped, though, possibly at the cost of inferior color.

Note, that's for TTTF, not the heaviest feeding grass around. I wouldn't do that to KBG, which likes to eat more regularly and spreads better if fed.

I thought I would check with those that are growing TTTF in the transition zone regarding your winterizer app. I haven’t applied mine yet. With the mild weather we are having the soil temps are in the mid to low 50’s during the day and mid to upper 40s at night. The air temp forecast next week is for the mid 60s with Wed. night being 52.

I need to apply sometime. What are your plans in this region?

grassboro wrote:I thought I would check with those that are growing TTTF in the transition zone regarding your winterizer app. I haven’t applied mine yet. With the mild weather we are having the soil temps are in the mid to low 50’s during the day and mid to upper 40s at night. The air temp forecast next week is for the mid 60s with Wed. night being 52.

I need to apply sometime. What are your plans in this region?

I applied my winterizing application on December 2. My weather has been wacky here in MD, just like the rest of the Mid Atlantic region with temps much higher than normal, but the top growth had stopped. I applied Expert Gardner 29-0-4 at rate that would give 1 lb of N per 1000 square feet. I think about 4% of that is slow release and I may lose that, but I should be okay. Of course, my soil is very sandy and we got almost 3 inches of rain last week, so we'll see how much hung around. My lawn is TTTF sod which was installed 3 years ago and I overseeded the first of October (a little late, but the warmer than usual fall has really helped me out). The grass took a real beating this past summer with the heat.

Like you, the weather has been so mild, that I am considering another feeding. However, I am kicking around a winterizer weed'n'feed since I had serious weed issues, and am trying to finish them off. The frost knocks what is left down, then a week of warm weather revives them. I will be putting down Tenacity at the end of February along with an aggressive seed drop.

Mind you, I am renting through next summer. We should buy then and I may be looking at an immediate August/September renovation depending on what I get. Therefore, all lawn work at our rental is a learning/experimental experience and is for my children to play on.

Ut oh. You really shouldn't use the terms "weed n feed" together. Pick out a winterizer and then treat the weeds. I have used weed b gone with good results.

I agree with GADad. Weed n feed gave me the worst experience. IF I had been renting I could have seen an owner possibly trying to charge me for the damage it caused had I not broke my back correcting it in the fall of 2010.

If I were in your shoes I would do nothing. Save your money for your new place you will own and use it to invest in YOUR property. There are always unexpected expenses and things that pop up in a new house and you may also end up doing a reno in 2012 (have you estimated ballpark costs of that? There are many things to consider and I am just a newbie here.)

nclawnguy wrote:I dropped turf builder today...we are supposed to have rain through Sunday. 32-0-10...18% urea. I was going to wait until after Christmas, but with all the rain coming i decided to do it now.

Yeah I thought about it, but with the temps in the mid 60s for so much of this month, I'm getting good top growth still...

I may be mowing into January at this rate. Definitely shows me how much I've improved the lawn over last year when I didnt have to mow in December.

BuckeyeChuck wrote:If I were in your shoes I would do nothing. Save your money for your new place you will own and use it to invest in YOUR property.

Did my wife find put you up to this??

I just wish my neighbor renting the house next door cared as much as you do about her own rental property lawn care. I was forced to put up a hedge to keep her destructive mowing habits on her own property. But I have ranted about that before... I know probably all of us have something to deal with..