I know Linda normally handles quiz duties, but I received a couple of intriguing pictures last week. Rather than just tell you all what’s going, I thought we’d have a little sport with it.
The photo below was taken last week ago at a container seedling nursery in western Michigan. These are trays of container-grown spruces. Most of the seedlings are green and growing but some are tip-damaged – with a specific pattern. What’s going on and what caused the pattern?
Based on the shape and regular pattern of the damage, I’ll guess the grower cut holes in the plastic to vent the house during our abnormally warm spring. Then we had the inevetiable cold snap(s) and frost and/or frigid air burnt the delicate new growth. My back up guess (are we allowed more than one?)is exhaust damage from a machine idlling in a certain spot – maybe the generator they used to run the conveyor belt down that huge central walkway?
Paul’s on the right track – the browning is frost damage. Now, why the pattern?
Though I don’t see any sprinklers, based on the “V”-shaped damage patterns, I’m going to guess the nipped patches are where sprinklers didn’t reach?
That was my first thought too, Terry. The underwatered seedlings would then be more susceptible to frost damage. (Though I’ll admit that frost hadn’t occurred to me, just the insufficient spray coverage.)
I think they were using their irrigation for frost prevention. They had to run all zones at once and therefore did not have enough pressure to cover what usually would be covered during a normal zone by zone irrigation schedule. It looks like there may be some sort of emitter on the center pole of the hoop house. A more birds eye view would show large circular areas of green and smaller frost damaged areas where they couldn’t quite achieve head to head coverage.