1. This says it's 15.5% Nitrogen and 19% Calcium. What's the other 65.5%?

It is mostly water. Calcium Nitrate formula is Ca(NO3)2.4H2O and that shows 4 molecules of water.

2. Can this be used as a foliar spray?

Yes, it can and it is the most efficient way to apply Calcium Nitrate. 

3. Will this product work in a potting mix diluted with water before application? (Not Hydroponics)

Yes, it will. This is 100% water soluble Calcium Nitrate and could be used in any form and it doesn't have to be in hydroponics. 

4. Can Calcium Nitrate be used to prevent blossom end rot in tomatoes and cucumbers?

Yes, it contains 19% Calcium and is the perfect product to prevent blossom end rot.

5. What's the difference between Calcium Nitrate and Ammonia Calcium Nitrate?

They are both the same product. However, due to the new California Department of Food and Agriculture regulations, we need to use Ammonia Calcium Nitrate on our labels. It is very similar to Potassium Chloride 0-0-62 or Muriate of Potash 0-0-62. They are also identical products and depending on the registration we might use either one of those names.

6. Can I use your Calcium Nitrate to feed orchids? If so, what is the application rate per gallon of water?

Yes, you can. The application rate depends on the quality of your soil / medium. However, for general / maintenance purposes we recommend applying 2-4 tablespoons per gallon of water. 

7. What is the application rate of Calcium Nitrate for hydroponics?

The amount of Calcium Nitrate needed for hydroponically grown plants depends on the system, the type of nutrients already added to the medium and the amount of plants present. However, our general recommendation is 1-4 tablespoons.