Putting the lawn mower away

[Badly Shaved Monkey]

Around about this time of year my temperate zone lawn barely needs cutting, but I've looked and haven't found a good description of the relative impacts on growth of various factors on growth: light, temp and water. The lawn seems to slow its growth in the summer even if we have a wet summer, although the higher temp and longer daytime than in the spring would, one would think, promote faster growth. That suggests grass is adapted to reduce its growth responses to those factors in the summertime.

Does anyone here know about this?

[Just thinking]

Originally posted by Badly Shaved Monkey
That suggests grass is adapted to reduce its growth responses to those factors in the summertime.

Does anyone here know about this?

I don't know personally about what affects the growth of grass, but I have heard (on several occasions) that letting grass grow to a longer length (not excessive) helps it develop a better root system, thus allowing it to get more moisture out of the soil during periods of dryness. So letting it grow a bit now and then may actually be best for it.

[mummymonkey]

Nothing gets grass growing quicker than rain. It doesn't need a great deal of sunshine. Just look at Ireland, a maritime climate is ideal.

[Dave_46]

My grass seems to get long very quickly. Its a good job my son is home from university.

Dave

[Badly Shaved Monkey]

Originally posted by mummymonkey
Nothing gets grass growing quicker than rain. It doesn't need a great deal of sunshine. Just look at Ireland, a maritime climate is ideal.

Yes, that's my alternative hypothesis: the grass looks like it packs up in the summer even in a wet summer because the summers here are never really that wet so rainfall becomes the limiting factor.

[rppa]

I notice the same thing, that the growth slows down in the hottest months of July and August, but really goes crazy in June and September.

On the other hand, as one poster suggested this could be due to rainfall. I think the hotter months here (PA) are also drier as a rule.

There are a lot of different grass species. I suspect this behavior depends a lot on the species, and you and I may just be looking at a species chosen for lawns in our particular areas.

[Badly Shaved Monkey]

Originally posted by rppa
I notice the same thing, that the growth slows down in the hottest months of July and August, but really goes crazy in June and September.

On the other hand, as one poster suggested this could be due to rainfall. I think the hotter months here (PA) are also drier as a rule.

There are a lot of different grass species. I suspect this behavior depends a lot on the species, and you and I may just be looking at a species chosen for lawns in our particular areas.

Yes.

http://www.ipm.ucdavis.edu/TOOLS/TURF/ESTABLISH/seasongrth.html

And tha is the information that has been easy to come up with. What has been hard to find is anything to show whether there is an underlying circannual rhythm or whether it is all driven by external factors, allowing that light is an external factor but would additionally be the likeliest entraining stimulus or zeitgeber (http://www.medterms.com/script/main/art.asp?articlekey=11607) to regulate a circannual rhythm.

[richardm]

Originally posted by Just thinking
I don't know personally about what affects the growth of grass, but I have heard (on several occasions) that letting grass grow to a longer length (not excessive) helps it develop a better root system, thus allowing it to get more moisture out of the soil during periods of dryness. So letting it grow a bit now and then may actually be best for it.

This is a brilliant excuse! Well done :D

[Zep]

In a country where the climate makes grass and lawn (a) a luxury, and (b) a total pest to maintain, I can assure all and sundry that it is indeed rain/water that is the trigger for grass growth.

I can leave my front yard for months at a time when it is dry and it stubbornly refuses to be more than a few disparate patches of weeds. But come the first decent rain or even heavy dewfall, and it all turns into deepest darkest Borneo out there (Sydney is very temperate, like LA).

Best way to keep your grass looking "lovely and dense" is to water it, cut it high and cut it often. Grass grows at the stalk, not the tip, so if you scalp grass it will die in patches. I should know - I have one of the world's best grass-patch collections... :(

[Rolfe]

I keep my lawnmower at medium and never scalp it. This year I didn't do the first cut till mid-April, and it was like mowing the Matto Grosso. Then I sprained my ankle at the beginning of May, when the lawn should have had the next cut. I couldn't get near it for three weeks, which made it five weeks since the April cut. Again, it was long and lush and a pain to mow. But it did look nice!

Then I got lazy. The weather got a lot warmer, and I had my mother staying, and for a month I didn't touch it. Then another two weeks, for various reasons. I finally did it yesterday afternoon. It wasn't that long over most of it, but it varied depending on the grass mix, and how much shade there was. Some bits were seeding away like mad.

It had rained several times, including a torrential thunderstorm, but overall I'm inclined to the climate theory. The hotter drier months are associated with less growth just because of lack of abundant moisture. We've got a hosepipe ban here, but even if we hadn't, it takes an awful lot of watering to make up for lack of rain. I've seen them do it on ornamental parks in Germany, and they pump water on at a phenomenal rate for severl hours every morning and evening. But they do get lush grass.

In fact the way the Water Board catches the hosepipe dodgers is just by flying a helicopter over the gardens. Anybody whose lawn shows up lush has some explaining to do. Of course, watering the lawn isn't forbidden, if you do it by hand. So, plead that you spend every spare minute out there filling watering cans...?

My mother's lawn in Scotland never seems to stop growing, but then it never stops raining long enough. Except that her neighbour mowed it for her while she was staying with me, and scalped it, and that did seem to put a bit of a crimp in its style for a couple of weeks.

Rolfe.

[Badly Shaved Monkey]

The reason why I think this is interesting is that if grass has an intrinsic cycle entrained, say, by the light cycle then it must have a biological clock like we do and it would be interesting to know about the mechanisms. However, if it is entirely a slave to external factors that is less interesting.

Zep's observations are more consistent with a total dependence on external factors.

In animals, clocks are found in specific organs of the brain. For them to exist in a plant they would either have to be completely decentralised or a specific organ would need to exist to house one.

If nothing else, I have been able to use the word zeitgeber for the first time in over 20 years!

[Badly Shaved Monkey]

Ah! Good old Google. If you chew the subject over, now search topics come up that you didn't think of.

Plants do have biological clocks;

http://template.bio.warwick.ac.uk/staff/amillar/circad.html

[Badly Shaved Monkey]

Plenty of stuff on circadian rhythms. Nothing on circannual rhythms so far.

http://www.answers.com/topic/circadian-rhythm

But this line;

"Many of the circadian controlled genes are involved in chilling and freezing tolerance."

would have implications for annual cycles.

Better yet;

http://www.plantphysiol.org/cgi/content/full/121/1/9

I haven't had time to read it all, but it doesn't mention grass so the question of my opening post remains unanswered. Nonethelss I'm reminded why I found this topic interesting when we did it in physiology all those years ago.