How to Save Tomato Seeds (and Cucumber & Melon Seeds, Too!)

How to Save Tomato Seeds
It's not too late to save seeds for next year's garden! And if you have ripe tomatoes (on the vine or on the counter), you can save tomato seeds. Some people think tomato seeds are difficult to save, but that's just not true. The trick is to ferment the seeds for a very short period of time before drying and storing them. And no - this process won't stink, contrary to what you may have read elsewhere. (The method outlined below is also ideal for saving cucumber and melon seeds.)

First, be sure you have open-pollinated variety tomatoes. Seeds from hybrid plants will be different from the parent and may sometimes be sterile; with open-pollinated/heirloom varieties, the seed will duplicate the parent plant. (And don't worry; there are no GMO tomatoes, cucumbers, or melons on the market...yet. Click here to learn more about seed types.)

EDIT 2/14/24: I'm sorry to say that there is now one tomato being sold to home gardeners that is GMO. It is called The Purple Tomato and was developed by (and is currently only sold by) Norfolk Healthy Produce. Although this tomato might seem tame compared to some GMO crops, it still unnaturally combines Snapdragon flower DNA with tomato DNA. In nature, this could never happen. The big concern here is that if The Purple Tomato pollen mixes with a traditional tomato's pollen (which can happen via the wind, insects, or other pollinators), it could cross-pollinate and create a whole new plant that would no longer give "pure" seed. 

Second, be sure you're using ripe tomatoes. (Or melons or cucumbers; cucumbers should be fully yellow before saving their seeds.) If you try to save seeds from unripe fruit, the seeds may not germinate when you plant them.

To Save Tomato Seeds:

1. Cut a ripe tomato in half and, using a spoon, scoop out the center pulp and seeds; place them in a jar. (Compost - or eat! - the outer part/skin of the tomato.)

Use a spoon to scoop away the seeds and pulp.

2. Cover the pulp with an inch or two of water and allow the jar to sit in an out of the way location. 

Cover the pulp with water.

3. Check the jar daily. The contents will begin to ferment, which will make the water cloudy; a whitish scunge called kahm yeast will also appear on the top.

Kahm yeast will begin growing on top of the pulp.

The liquid in the jar will turn cloudy.

4. As soon as you see these signs of fermentation, strain the mixture and pick out the seeds. (If you let the mixture sit longer, it may begin to stink.) The gelatinous sac surrounding the tomato seeds should be gone. If it's not, return the tomato pulp to the jar, cover with water, and allow to sit another few days.

Unfermented tomato seeds in their gelatinous sack.

Straining the fermented tomato seeds.

5. Lay the sac-free tomato seeds on a plate and allow them to dry for a day or two. 

6. Place the dry seeds in a glass bottle or jar with a well-fitting, metal lid. Store seeds in a cool location. (For tips on storing seeds properly, click here.)

Dried tomato seeds.

Store dried tomato seeds in a glass jar with a metal lid.


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