It only takes inch of moisture to activate Velar, whereas it takes a 1-inch rainfall event to activate Sinbar. I have never seen January-February applications of Sinbar or Velpar give adequate control of summer weeds. However, there are several limitations with using Zorial. Also, Zorial will not control summer broadleaf weeds, nor does it control all of the summer grass species that can occur in alfalfa. However, summer weeds are usually not a problem in dry summers.
Every spring there is interest in planting alfalfa.
Producers planning to sow alfalfa spring should be making final plans now. Spring-sown alfalfa in Oklahoma is more risky than fall planting. This is primarily due to more problems with strong drying winds, insects, weeds, and intense rains that tend to crust the soil. Spring sowing is more likely to be successful in the eastern half of the state where rainfall is higher. Exact steps required for successful stand establishment vary from farm to farm and from year to year, however, there are at least 12 Keys.