Have you ever noticed that one time a foliar works and the next time or in a different field it doesn’t? Here are a few reasons why you may have the problem.
You should have a minimum of 1800 pounds of plant available calcium as reported on a Morgan test. The only lab that I know of that does this test is International Ag Labs (www.aglabs.com). Ask for an S3 test and I also get an S5 test at the same time.
The next thing to consider is the strength of the mix. If it is too “hot,” the plant will not take it in as it will burn the foliage of the plant. WE all like to use as little water as possible, but this is not always a good idea when applying foliar nutrients.
One other thing to consider is that sometimes the plant roots or soil biology might need the nutrients more than the upper parts of the plant and they might stay below ground. In this case you will not see a response on the plant.