Wild Gourd Farm

Organic Gardening in St. Louis City

Tag Archives: tomato seeds

Saving Tomato Seeds

It makes sense to save seeds. We love looking at seed catalogs each year and ordering new varieties or things we’ve never tried before, but it’s even more satisfying to look at our own seed collection. Saving our own seeds each year is economical, plus it gives us the power to select for traits of our choosing. By saving seeds from the best tasting tomatoes, or the ones that ripen first, or those from plants displaying the best disease resistance, we’re breeding from generation to generation the best plants for our purposes and climate. This kind of control has been systematically stripped from lots of farmers through the sale of hybrids and genetically modified crops, from which seeds cannot be physically or legally saved.


Anyway, saving tomato seeds is pretty easy, if you know what you’re doing. The hardest part of seed saving is ensuring a “true to type” second generation- meaning the resulting plants will be genetically similar to the parent plant(s). The good thing is tomatoes are largely self-pollinating so it’s unlikely you’ll get unwanted hybridization or cross pollination, even if multiple varieties are planted in close proximity. So saving seeds from any non-hybrid or non-GM tomato will most likely result in a “true” plant. The other great thing about saving seeds from tomatoes is that you still get to eat the fruit! Lots of times the crop itself must be sacrificed for the seeds (like allowing greens to bolt), but not tomatoes!

To save tomato seeds, you can simply remove the seeds, allow them to try, and package them up for next year. However, it is highly recommended that you ferment the seeds first. You know that gelatinous coating around tomato seeds? It inhibits seed germination inside the tomato, which normally provides a rather alluring dark, moist environment for seeds to start growing.  Fermenting the seeds removes that coating, reduces seed-borne diseases in the next generation, and helps you separate the good seeds from the bad.

Fermenting the seeds is easier than it sounds! Simply squeeze the seeds and goo out into a small cup or dish (I’ve even used shot glasses). Don’t worry about getting some tomato flesh in there, you’ll get rid of it later. If there’s not much liquid or gel you can add a little water, but not too much!

Loosely cover each container with plastic wrap. Some people recommend keeping them open or poking holes in the covering, but that can be a recipe for fruit flies. As long as there’s a little breathing room, you’re good.
 Don’t forget to label! I use a permanent marker to write directly on the plastic wrap so there’s no confusion. Once labeled, put in a draft-free spot out of direct sunlight for a few days.
Depending on conditions inside your house, you should see a layer of mold begin to form after 2-3 days. You probably don’t usually rejoice at the sight of mold, but this is a good thing! It means that the protective gel is breaking down. In a way, the fermentation process is mimicking the natural action of a tomato rotting on the ground. In nature, the seeds don’t become “active” until after the fruit has rotted.
tomatoseeds1 After the mold forms, you get to start a process of decanting to remove the mold and unviable seeds. Fill your container up with water. The good seeds will sink to the bottom, and any bad seeds will float. Allow to sit for a minute, then slowly pour the water into your sink. You’ll notice you’re pouring off any tomato pulp and bad seeds with the water. Refill with water and decant until you have clean seeds.
tomatoseeds3 The last step is drying. Some people prefer to use screens or paper plates to ensure even drying, but I like to use ceramic dishes. If you move the seeds around occasionally you shouldn’t have a problem with them sticking and breaking, plus the plates allow you to keep varieties separate. I like to label the plates with non-toxic dry erase marker, which cleans off easily. Keep them out of direct sunlight and monitor for moisture daily.
 You’ll know when your tomato seeds are sufficiently dry. They’ll get a slightly fuzzy outer texture. They should break instead of bending, if you feel like sacrificing one of your seeds. It’s a good test, especially if you’ll be storing them long term (mold was good in fermentation, but not in storage) or in the freezer.



We store our seeds inside biodegradable plastic bags in a dark cabinet in our basement. Many people use paper envelopes to ensure for proper breathing and to prevent moisture buildup. No matter how you choose to store your seeds, it’s always a good idea to label them with the variety, the year, and location of harvest.

Last year I started a free community seed library at Local Harvest Grocery, which you can read about here. Anyone can “borrow” seeds with the pledge to save and return some for the next year. As more people participate, we’ll grow a diverse collection of seeds that thrive in our area. If you live around here, feel free to stop by for some seeds, literature on seed saving, or just a friendly chat 🙂 As you can tell, I love nerding out about seeds!