How to Save Tomato Seeds to Grow Next Year

Anyone who has composted leftover tomatoes has probably had the experience of seeds from those tomatoes "volunteering" in the garden if the compost that has overwintered is then used as a soil amendment or mulch the following spring. Or perhaps you've seen tiny tomato volunteers spring up in the garden where tomatoes have fallen off the plant the previous year. Tomato fruits are laden with tiny seeds that will readily sprout if they reach the soil. But rather than waiting for accidental volunteers, it's quite easy to save seeds from tomato fruits so you can plant them exactly when and where you want.

When to Save Tomato Seeds

Tomato seeds can be collected from fruits that are fully ripe, from mid-summer to fall. Tomatoes are a rather slow-growing plant, so most gardeners will want to start these seeds indoors quite early in the spring. It can take tomato seeds six to eight weeks to become viable seedlings, then once planted outdoors, the seedlings may require as much as two months to produce ripe fruit. This varies somewhat depending on the variety and size of the tomatoes—small cherry or pear tomatoes will begin bearing fruit much faster than large beefsteak tomatoes, for example. But overall, tomatoes are one of the slower-growing vegetable plants.

Working With Tomato Seeds

Seeds from many plants can be saved simply by waiting for seed pods or fruit to dry, then opening them up to collect the seeds. Tomatoes take a bit more work because their seeds are enclosed in a gel-like sack that contains growth inhibitors to prevent the seeds from sprouting inside the tomato. The best way to remove this gel covering is to allow the fruits to rot and ferment. In nature, this happens when the fruit falls off the plant. For seed savers, we're going to speed up the process.

The first step is to choose your best-looking tomatoes. You want to save seed from the finest fruit, so that next year's plant will have good genes. Remember you should only save seeds from open-pollinated (OP) tomatoes. That includes all the heirlooms. Seeds from hybrid tomatoes, while they may sprout and grow, often produce tomato plants that revert to one of the genetic parent plants, which can produce much different fruit than you're expecting.