Most brands of fertilizers do not have an expiration date, how do you know when a product expires? It is true that the vast majority of fertilizer brands do not have an expiration date, for the simple reason that it is not possible to say exactly on which day a product expires. Saying “expires on May 10, 2014” is not the same as saying “better to consume before May 10”; The first implies that the product will deteriorate from that day on; the second, that from that date the product may begin to lose properties, but that it can continue to be used (it is like with the yogurt issue: they can be consumed after the indicated date).
As a general rule, if the bottle is closed, the product can be kept in good condition for about four years; some organic products possibly a little less. Once a container has been opened, it must be consumed within a year.
If you have had a boat open for more than two years, it is most likely already in bad shape.
The environment where the product is stored also has a lot to do with it. Be careful not to expose the products to full sun and do not store them in places with too much heat or cold. The minimum temperature that the place where they are stored must have is about 5 °. Below that temperature, the most normal thing is that a reaction called crystallization takes place and, therefore, the liquid becomes a solid paste; that is to say, useless.
All well-known brands work with batch codes. These numbers are usually printed or marked on the bottles or caps and indicate, among other things, the date of manufacture and not the expiration date.
If there is a problem with a product, we recommend contacting the manufacturer, who will ask for the batch code and will know how to detect when it was manufactured to find the fault, if any, and find a solution to the possible manufacturing problem; This is called traceability, and all manufacturers are required by law to implement it in their production system.
We recommend that you always buy in stores that have a lot of movement and that have not had the product for months or years on the shelf. Many times the fertilizer has been waiting for a long time to be bought and all these calculations that we have just indicated are useless, because we do not know how long it has been in the store (and how long the distributor has had it previously). For this reason we are advocates that at least the production date is printed on all fertilizers, but of course, this is contrary to the commercial interests of many.