How to Save Tomato Seeds: Step-by-Step Instructions

Saved properly, dried tomato seeds can last years.

bowl of tomatoes in red colander with outstretched hand holding dried tomato seeds

Treehugger / Sanja Kostic

Overview
  • Working Time: 1 hour
  • Total Time: 1 week - 1 week, 3 days
  • Yield: 100+ seeds
  • Skill Level: Beginner
  • Estimated Cost: $0

When you buy new seeds at the store, they often come from large companies that treat their crops with pesticides and other hazardous chemicals. Saving seeds from your own produce each year is a more environmentally friendly alternative.

Tomatoes are great crops for beginner seed-savers because their seeds are easy to extract and work with. Choose plump, brightly colored, ripe tomatoes without blemishes for this project, as their seeds will be easier to remove than unripe ones.

Any tomato variety will work, but make sure the parent plant is an open-pollinated variety (an Heirloom tomato, for example) and not a hybrid, or cross between two tomato varieties. Seeds from hybrids won’t produce offspring with the same traits as the parent plant, but seeds from open-pollinated plants will.

open hand holds dried tomato seeds surrounded by fresh tomatoes and kitchen equipment

Treehugger / Sanja Kostic

What You'll Need

  • Container with lid
  • Strainer, fine sieve, or cheesecloth
  • Large mixing bowl or bucket
  • Several ripe tomatoes
  • 1 paper plate (more as needed)
  • 1 envelope (per tomato variety)

Instructions

  1. Harvest Tomatoes

    hand reaches out to puck ripe red tomato from growing tomato vine in garden

    Treehugger / Sanja Kostic

    Carefully pluck ripe tomatoes from healthy parent plants. In order to selectively breed the best tomatoes possible, only choose tomatoes that are in good condition.

    Avoid tomatoes that are misshapen or come from plants with pest damage, as those traits may be hereditary and the seeds you save from them may experience similar setbacks when they grow.

  2. Remove Seeds, Juice, and Pulp

    hands hold up small tomato cut in half, with kitchen tools and tomatoes on wooden table

    Treehugger / Sanja Kostic

    Cut each tomato in half and squeeze the seeds, juice, and pulp of your tomatoes into a container (a glass canning jar works).

    Make sure the seeds are completely covered with pulp and juice so they can properly ferment. Avoid adding water to the mixture if possible, as dilution can slow the fermentation process you’ll rely on to save the seeds.

  3. Start Fermentation

    hands reach for lidded glass jar labeled tomato seed ferment on kitchen table

    Treehugger / Sanja Kostic

    A jelly-like sac surrounding each tomato seed prevents germination until the seeds are exposed to soil, which is great, except that the sac can harbor disease. Experienced seed-savers use fermentation to rid the seeds of their sacs before drying and storing them for future use.

    Once the seeds, pulp, and juices are all squeezed out into a bowl, label the bowl “tomato seed ferment” with the date and set it aside to let the fermentation begin. You can cover the container with a lid or cheesecloth to keep fruit flies away and to help contain the ferment’s unpleasant smell.

  4. Check on Fermentation

    overhead view of fermented tomato seed mixture with white mold growing on top

    Treehugger / Sanja Kostic

    Leave your seeds to ferment for 1 or 2 days and check on the process once or twice daily. Fermentation times longer than three days can negatively impact the seed’s viability. After fermentation, the mixture of seeds, pulp, and juice should have a thin layer of mold over it. This may look and smell gross, but it’s a sign that the fermentation process is working.

    If there is no layer of mold after 2 days of fermentation, don't worry. It may not have had time to develop yet, but that doesn't mean the ferment didn't work. Check to see if the seeds have all settled at the bottom of your container with layers of watery juice and then pulp on top. If these layers are present, your ferment is complete.

  5. Pour Out Liquid

    hands pour out fermented tomato seeds into small sieve to strain out excess liquid in glass bowl

    Treehugger / Sanja Kostic

    Pour out excess liquid from your tomato slurry, including all pulp, juice, and mold that may have formed in your container.

    You’ll strain the mixture again in the next step, so there’s no need to completely separate the seeds yet. Just pour off what you can without sacrificing seeds to make the straining process easier. Dispose of unneeded pulp, juices, and mold in your compost bin.

  6. Strain Mixture

    hands run cold water from sink over fermented tomato seeds in small silver sieve

    Treehugger / Sanja Kostic

    Now pour the seed mixture through a cheesecloth or a fine-mesh sieve into a separate large bowl or bucket to completely separate all seeds from the liquid. You can spray any stubborn pulp with your water faucet.

    Rinse the seeds thoroughly under running water to get rid of all of the pulp and juices possible. Again, you can dispose of the unneeded pulp in your compost bin.

  7. Dry Seeds

    tomato seeds dry out on white paper on wooden table in light sun with sieve nearby

    Treehugger / Sanja Kostic

    Drying tomato seeds completely after fermentation will allow them to stay viable for up to 10 years. To do this, you can flip the strainer over and empty the clean seeds onto paper plates.

    Spread the seeds out so they have room to dry. Set them aside until they are completely dry (about a week) in a relatively cool, well-ventilated area. To stop the seeds from clumping together, shake the plate daily and rub away any clumps that do form.

    If you’re drying multiple tomato seed varieties, make sure you label them and avoid mixing seeds to prevent cross-contamination. That way, you’ll know exactly what you’re planting when it’s time to garden.

  8. Store In Envelope

    hands place dried tomato seeds in white envelope, about to seal

    Treehugger / Sanja Kostic

    When your tomato seeds feel dry and papery you’ll know they are completely dehydrated. Then, place seeds into an appropriately labeled sealable envelope for future plantings.

    If you are saving seeds from multiple different tomato varieties, place each variety into a different envelope and label it to avoid any mix-ups.

Storing Tomato Seeds for Future Use

tattooed hand places dried tomato seeds in white envelope in kitchen freezer

Treehugger / Sanja Kostic

Tomato seeds can stay viable for up to 10 years when fermented, dried, and stored in a cool, dry place. You can store them in your refrigerator or freezer in an airtight container for extra protection.

Fermenting the tomato seeds isn’t the only way to preserve them. You can omit the fermentation steps and simply clean and dry the seeds. If you dry your tomato seeds without fermenting them, they will only last 1 to 2 years. This is a good seed-saving option for those who plan to use their seeds quickly.

Frequently Asked Questions
  • Can you try this method with store-bought tomatoes?

    Indeed, you can also save seeds from tomatoes you buy from the supermarket, but make sure they're organic and preferably locally grown. Note that you don't know what kind of diseases the tomato's mother plant might have harbored, so results will vary.

  • Should you save the seeds from heirloom tomatoes?

    Heirloom tomatoes sold in the U.S. come from South America. and some varieties are patented—meaning, they're illegal to grow. Even growing small crops of them for home use isn't permitted because patented genes can travel through pollination.

  • So, which tomato varieties should you plant in your garden?

    Some of the most popular varieties include beefsteak, juliet, and cherry tomatoes because they're among the easiest to grow. When choosing a variety, consider your climate, your desired plant yields, time to maturity, disease resistance, and what you plan to use the tomatoes for.

  • What other veggies can you do this with?

    In addition to tomatoes, you can also save and replant the seeds from beans, peas, and peppers.

View Article Sources
  1. "Seed Saving." UMass Extension Center for Agriculture.

  2. McCormack, Jeffery H. "Seed Processing and Storage." 2004.

  3. McCormack, Jeffrey H. "Tomato Seed Production." 2004.

  4. Karavina, C., et al. "Assessing the Effects of Fermentation Time on Tomato (Lycopersicon lycopersicum Mill) Seed Viability." Journal of Sustainable Development in Africa, vol. 10, no. 4, 2009, pp. 106-112.