Q: I have been impatiently waiting until my zoysia grass has greened 75-100 percent. Why must I do this, other than because you say so on your website?
A: You’re a smart person to always be asking “Why?” in the garden.
The reason to delay zoysia fertilization is that it can not use fertilizer until it has an active root system. It won’t have an active root system until it has green shoot growth AND soil temperatures are above 65 degrees. Because zoysia doesn’t have a lot of stored reserves from winter, all it takes to severley weaken it is an early fertilization combined with a late freeze.
Soil temperatures near you in Gainesville just broke through 60 degrees a few days ago (in late April)…but who wants to go out and stick a thermometer in the soil?
The easiest way to describe when conditions are right for feeding zoysia is to say “Wait until it is 90% green”. That’s when you know the grass can use fertilizer appropriately.
If you want a concrete example, a neighbor’s lawn service fertilized her ‘Emerald’ zoysia in mid-March, 2007. Warm temperatures followed…until the Easter freeze hit on April 6.
More than 50% of her lawn was killed. It did not recover for two years…and then, only because she sprigged in lots of zoysia in the bare areas.
THAT’S why we wait until zoysia is 90% green!