How to Save Tomato Seeds

Growing vegetables from seed is a hugely rewarding process. But it can be expensive to buy new seed packets year after year. And once you find a variety you like, not being able to source those seeds the following spring can be frustrating. There is one way around this however. Learning how to save tomato seeds is a cost effective way of ensuring that you always have a fresh, viable supply ready to sow.

Whether you are a committed gardener, growing your own food all year round, or a newcomer to this fabulous pastime, even if you are simply growing a few tomatoes indoors, knowing how to save tomato seeds is a supremely useful skill. This guide will teach you how to save tomato seeds.

Learning how to save seed is an incredibly useful skill that is easy to acquire. 

Selecting the Right Tomatoes

Learning how to save tomato seeds begins in the summer as your tomatoes ripen on the vine. If you are growing more than one plant, identify the healthiest specimens with the best tasting fruit.

While you can start earlier, the best time to harvest the seed is from mid summer until fall. Select healthy fruit that is free from bug holes and cracks.

Only ever use seed from open pollinated tomatoes. Heirloom varieties are ideal. Avoid seed harvested from hybrid varieties. While the seed will germinate it won’t be a true replica of the parent plant. This can be disappointing.

If you are growing different types of tomatoes, such as big beefs and cherry toms, select fruit from plants grown far apart to guard against cross pollination. Try to avoid double fruits, these are more prone to cross pollination than single fruiting plants.

Harvest seed from healthy fruit. 

After harvesting, wash the fruit before cutting them open to access the seed. Select the largest seeds, these are most likely to be healthy and viable.

Now that you have them, it is time to learn how to save tomato seeds.

The Fermenting Process

An important part of learning how to save tomato seeds is being able to correctly clean and store them. If you want to keep the seed for an extended period then fermentation is a necessary step. If cleaned and dried correctly the seed can stay viable for around 5 years.

The seed is enclosed in a gelatinous sac. This contains chemicals that prevent the seed from germinating until it is planted. While this is great in nature, enabling the seed to survive the winter months before sprouting as temperatures warm up, the gelatinous sac can provide a hiding place for seed and soil-borne disease. If allowed to remain in place on just one seed, a disease can ruin our entire seed store. To ensure this doesn’t happen we must properly clean the harvested seed. This is easily done by fermentation.

Fermenting is simply a way of cleaning the seed so that the gelatinous sac is cleaned away.

Soak the seed and surrounding pulp in a jar of fresh water. Check the seed and water mixture every day. You are looking for smelly mold or scum forming on the surface. When bubbles start rising from the mixture or when the entire layer of pulp is moldy it is time to remove the seed.

Source: https://www.youtube.com/watch?v=hQQdRa6KAcA 

Fermenting can take up to a week. Today, some growers prefer to simply soak the harvested seed for one to three days, believing that soaking a seed for more than 3 days has a negative effect on germination.

To clean the harvested seed without fermenting it, soak the seed in fresh water for 24 hours at room temperature.

The following day, rinse the seed with a strainer or in a sieve.

Dry the seed on paper for around a week, until it feels dry and papery.  If you are saving more than one variety, remember to keep each seed variety separate. Label each piece of paper with the name of the variety. Store the fermented seed in a sealed paper envelope or air tight jar, such as a small Kilner Jar.

Drying without Fermentation

If long term storage is not a priority or you want to know how to save tomato seeds for use the following year then you can simply dry them without undergoing the fermentation process.

Cut open the fruit to easily access the seed. 

Open up your tomatoes and separate the seed from the fruit. Spread the seed out and place them on a paper plate or a sheet of kitchen paper in a warm, sheltered position, such as a greenhouse shelf, to dry. When the seed has dried, fold up the paper and store overwinter in a labeled envelope. This method is ideal for gardeners who want to learn how to save tomato seeds for use next year.

How to Save Tomato Seeds by Burying Them

This simple method is perfect for gardeners who like to plan ahead. If you adopt even a basic crop rotation system you will know where you will be planting your tomatoes next year. Towards the end of summer, space in next year’s position clears. After making any necessary amendments, bury either tomatoes cut up or the separated seed roughly 2 inches deep in the desired position. A depth of 2 inches is deep enough to protect the developing seed from harsh winter temperatures but not too deep that the seed won’t germinate. Cover with an equal amount of soil and mulch. You can also bury the seed in pots or planters.

In the spring, remove the mulch and place a cloche over the soil. Covering the soil helps to warm it up, encouraging germination. These Cabilock Reusable Garden Cloches are easy to secure in place, warming the soil and protecting young plants from cold temperatures and pests.

Burying the fruit in position in late summer is an easy way to get new plants next year. 

Learning how to save tomato seeds is a pleasingly easy process. It is also an incredibly useful skill for even casual gardeners to have. Knowing how to save tomato seeds, or any other seed, enables you to continue sowing your favorite crops year after year without the expense or trouble of sourcing seed packets. Once you’ve mastered how to save tomato seeds you can even start swapping varieties with other gardeners.