The simple answer is “from yourself”. The only way this can happen is if you are already practicing the skills you need to secure the best possible seeds for next year’s crops. Sure, many gardeners will tell you to choose the best plants to get the best seeds, but what they don’t tell you is how to consistently improve, over time, your ability to harvest the best produce possible. As a matter of fact, you could produce a new variety of seeds through your efforts.
Start with the best quality seed you can get. Seeds are expensive, so do your research. Just because you have bought this or that brand for year after year does not mean you are in fact buying the best.
One of the most important things you can do is to keep a proper journal about your garden exploits. Write down everything, every year. Date every page. Did it rain today? How much? Was it hotter or colder than normal today than last year on this day? Note it and log it. What did you plant today? Remember to log the germination rate each day. There is no detail too small to consider adding to the journal about your garden or fields. Why? Because you will need that information after a WCE. Then it will be too late to start gathering useful information for your region. It takes years to gather what you need. Some of it you can get from local garden experts, but your own experiences are more valuable than anyone else’s.
Test the germination rate for the seeds you plant every year. You will know the rates for each company from which you buy seeds. In this way you will better choose products that meet your needs best. It is with these seeds that you will start your seed saving practices as well as your venture into creating a better and stronger variety of your favorite produce.
When your plants are growing in the garden, continually watch them to see which are the best and worst. When it comes time to harvest seed, choose only to harvest from the single best plant that has the best qualities you desire. For the next planting season complete the steps over again. Be sure to plant these seeds away from the possibility of pollination by any other source.
Each careful harvest gains seeds that are best suited to your environment and most resistant to the pests and diseases of your region. In this manner you will create your own variety of plants and seeds. Those, and your reputation for seed production will be valuable after a WCE.