Did you grow something amazing this year and would like to plant it again next year? As long as you started with non-hybrid (heirloom) plants or seeds, you can harvest seeds from this year to store and plant again next season. Different types of seeds require extra preparation before storage and we will review some of the most common types.
Beyond starting with heirloom varieties (you can read more about the reasons behind this in our previous blog post), isolation is another consideration if you want to save seeds. Certain crops depend on insects or wind for pollination. If you plant different varieties of the same species too close together, it’s possible that your crops may get cross-pollinated. Cole crops like cabbage, kale, and broccoli are just some vegetables susceptible to cross-pollination. When that happens the seeds that develop will not be true to the breed you started with. If you are just getting started with seed saving, you can keep it simple by planting only one variety of species to prevent cross-pollination.
Start with Mature Seeds
One important thing to know before you harvest your seeds is whether or not the seeds are fully mature. There are many plants that we harvest to eat long before they have produced mature seeds. Some examples are cucumbers, eggplant, beans, and carrots. If you want to be able to keep seeds, leave some of the fruit on the plants to fully mature. This means leaving your bean pods on the vines until they are brittle and dry, leaving some eggplants and cucumbers on the vines until they are overripe and starting to shrivel, or leaving some carrots in the ground until the tops have gone to flower and are starting to dry.
Harvesting “Wet Fruit” Seeds
Crops can be classified as wet fruited or dry fruited. Wet fruited crops are things like tomatoes, cucumbers, squash, and eggplant. With wet fruited plants, you will have to open up the fruit and remove the seeds from the flesh and the pulp. For most wet fruits, you can simply rinse the seeds well with water and then spread to try on screens or coffee filters for a few days until the seeds are nice and dry. If you can snap a test seed in half, it is dry enough to be stored.
Tomatoes & Cucumbers
Tomato and cucumber seed harvesting requires a slightly different process than most wet-fruited plants. Their seeds have a special membrane surrounding them that needs to be removed before you can dry and store the seeds. To remove the membrane, ferment the seeds for a few days.
To do this:
- Cut open your fruit and scrape out the seeds and surrounding pulp.
- Try to remove as much of the pulp as possible and add the seeds to a clean jar and cover with at least an inch of non-chlorinated water.
- Cover the jar loosely with the lid, a cheesecloth, or a coffee filter to allow adequate airflow, and let it sit at room temperature for several days.
- The surface of the water will eventually be covered with a foamy white film and smell a bit sour (this is yeast produced from the fermentation process).
- Once the film has covered the entire surface of the water, you can pour off the film and any seeds floating at the top.
- The good seeds should have sunk to the bottom of the jar.
- Rinse your seeds well with water in a fine mesh strainer and then spread them on a glass dish to dry out for several days. Don’t use a paper towel for drying your seeds as they may stick and be damaged when you try to remove them.
Eggplants can be another special case because the seeds are so small and embedded throughout the fruit.
To harvest the seeds:
- Cube the fruit and add it to a food processor with some water.
- Pulse to turn the fruit into a slurry.
- Pour the slurry into a larger container and add more water.
- By agitating the container, mature seeds will sink to the bottom. You may need to repeat this process a couple of times to get rid of most of the pulp.
- Pour off the pulp and rinse your seeds well in a fine mesh strainer then spread on screens or a coffee filter to dry.
Harvesting “Dry Fruit” Seeds
Harvesting seeds from dry fruited plants is generally as simple as waiting for the seeds to mature on the plant and then harvesting them. The key is waiting for the seeds to mature. This means for plants like beans and peas that produce pods, you will need to leave the pods on the plants until they are brown and dry. If you cannot leave the pods on the plants due to the arrival of frost, you can pull the pods and allow them to dry out on screens and then harvest the seeds. You’ll know the seeds are ready if they are dry enough to not dent when you press with a fingernail. For root vegetables like carrots, beets, and radishes, you’ll want the plant above ground to grow to maturity and go to flower. When the flowers are starting to dry, you can remove the seeds.
Another Special Case
Garlic is another special case as it is vegetatively propagated rather than grown from seeds. What this means is that you will harvest cloves from this year’s garlic and replant those. While garlic can be allowed to produce flowers, the seeds may not be true to type. When you harvest your garlic in late Summer, choose your best bulbs to keep for replanting. Allow the bulbs to dry until the skin is brittle and papery. When you are ready to plant, break apart the cloves in the bulb and plant with the point side up. Garlic is planted in the Fall, covered with mulch, and left to overwinter.
Storing Your Seeds
Once you’ve harvested and dried your seeds, it’s time to store them properly so they will be viable when you are ready to plant them. Avoiding moisture, light, and heat are the primary factors in proper seed storage. You’ll want to store your seeds in airtight containers in a cool, dark environment. You can safely refrigerate or even freeze your seeds as long as they are in an airtight container. Most properly stored seeds will remain viable for 3 to 5 years.
We Provide the Instructions
All packets of our heirloom seeds contain not only planting instructions but details on how to harvest and save the seeds. Our larger seed collections like the Home Garden, Homesteader, and Farmer's collections also come pre-packaged in reusable airtight containers to allow you to create your survival seed vault. We understand the important part that seeds play in survival and sustainability and want to support you on your journey to expanding your garden seeds.