Light Green KBG in Spring only

[gryd]

Every spring my lawn darkens up in late April. The color of my KBG is pretty dark with the exception of small patches of light green grass scattered throughout my lawn (see Image 1). The lighter green grass has rhizomes and a blade that is distinctly Kentucky Bluegrass (see images 2 and 3). It is not Poa Trivialis. By late May the light patches darken up and are no longer noticeable. Is this normal? Does anyone else notice something similar?

Image 1


Image 2


Image 3

[MorpheusPA]

Normal. I get exactly the same thing; the brighter patches are more actively-growing while the deeper patches are growing more slowly, and haven't quite caught up yet. The bright's because it's in active growth.

By late May, active growth slows, colors deepen again, and the whole thing evens out.

[gryd]

Thanks Morph. I believe you are correct but I wonder if cultivars may play a role in some KBG being lighter green this time of year. I have many dark patches growing vigorously from dog urine. Below is an image with dark green/blue KBG growing actively next to a light green patch growing at about the same rate. Any idea what explains this phenomenon?

[MorpheusPA]

I've figured the same because I also get the same, and thought the cultivar probably had some influence. I've never quite put my finger on it, either, but the Midnight II and related cultivars seem to come back a bit later than anything else (and always be darker). In my case, the Bedazzled is earlier but brighter green.

Over time, the Midnight variants are dominating my lawn.

[gryd]

I've figured the same because I also get the same, and thought the cultivar probably had some influence. I've never quite put my finger on it, either, but the Midnight II and related cultivars seem to come back a bit later than anything else (and always be darker). In my case, the Bedazzled is earlier but brighter green.

Over time, the Midnight variants are dominating my lawn.

Thanks Eric. I imagine soil has something to do with color in this case as well.

[MorpheusPA]

Absolutely. I just hit mine with molybdenum (undetectable on my test), boron (very low), and copper (low) and color has never been better. I got the extended ($30) test this year, I'll do so next year just to make sure I hit the groove, then won't need it again for ten years.

[gryd]

Absolutely. I just hit mine with molybdenum (undetectable on my test), boron (very low), and copper (low) and color has never been better. I got the extended ($30) test this year, I'll do so next year just to make sure I hit the groove, then won't need it again for ten years.

Thanks for the reminder. I need to get my soil tested asap.

[gryd]

Absolutely. I just hit mine with molybdenum (undetectable on my test), boron (very low), and copper (low) and color has never been better. I got the extended ($30) test this year, I'll do so next year just to make sure I hit the groove, then won't need it again for ten years.

I fertilized a week ago. The light areas have darkened up. In that case then wouldn’t the lack of nutrients in some areas of my soil be responsible for the light bluegrass?

[MorpheusPA]

Probably. Slowing growth as we move into June also helps. Mine evened out in late May, like it always does, and it's now practically undetectable.

It's surprising how some nitrogen will mask a shortage of other nutrients, though. I've poured that on the gardens for years, not really realizing that my calcium levels were kind of low, molybdenum was lousy, and boron downright terrible.

Well, OK, the last I could calculate just by simple logic and I kind of suspected the first.