Month: January 2006

Tomato seeds are one of the easiest types to save. Tomato plants are mostly inbreeding, meaning it’s unlikely tomato plants will cross pollinate with each other and plants grown from the saved seeds will produce more tomatoes of the same type.

Seeds can only be saved from open pollinated or heirloom types. Seeds saved from hybrid types will likely be genetically unstable and lead to unpredictable results.

Ideally, tomato plants will be grown a half meter apart in rows 1 meter apart. Preferably you will grow about 5 of the same type in a row, and save seeds from the middle 2 or 3 plants. In this way, you will have some genetic diversity by using more than one plant, and you will minimise the already small risk of cross pollination by isolating the varieties from each other with a little space. In doing this, your rate of crossing should be far below 5%. If you can’t do this, or you only have 1 or 2 plants of each variety, don’t worry, you will probably achieve good results no matter what.

There are contradictory reports of wild or currant tomatoes crossing with each other and with other tomatoes. To minimise the risk of crossing, don’t grow these types of tomatoes near any other plants except those of the identical type when saving seeds.

Only save seeds from the most tasty and good looking tomatoes to ensure you do not select any that are genetically predisposed to be of poorer quality. If possible, select seeds from the first few tomatoes that ripen on each plant, as these are likely to have the healthiest seeds.

Okay, on to the seed saving part. Fermenting seeds helps prevent some diseases, and also removes the gelatinous coat on the seeds. If you don’t wish to ferment them, just skip the steps below and spread them out on a coffee filter to dry.

To ferment the seeds, first slice your tomato or tomatoes along their equator, and scoop the seeds into a non metallic fermenting container. If desired, you can add a few tablespoons of water, but it’s not necessary. Cover the container with plastic wrap, and poke a few holes in it. Put in a warm place (about 70F or 22C), protected from direct sunlight, and leave undisturbed for 3-5 days. Fermenting is an anaerobic process, meaning exposure to oxygen will disturb it, so the contents of the container should not be stirred. There will be a layer of slimy mold growing on top and, after fermenting, you should scoop as much of this off as possible.

Now rinse the seeds off by holding the fermenting container under slowly running water. Mostly the seeds will sink to the bottom, and everything else will float. By gently helping the debris over the edge of the container with the running water, you will be left with only seeds. If any seeds do float, they are bad, and you can let them wash away.

Now pour off as much water as possible, and put the seeds on a piece of coffee filter paper to dry. Do not use any other type of paper like a paper towel, or the seeds will stick. At this point you have about a week to completely dry the seeds before they start germinating. Place them in an airy place, protected from direct sunlight.

When they are dry, put the seeds in a paper or plastic envelope and store at a steady temperature in a dry place. Only store them in plastic if they are completely dry.   Some place dark without frequent temperature changes like the back of a closet or cabinet is a good choce of storage location.  Properly stored seeds will last about 10 years.

All vegetable seeds have a limited shelf life. This ranges from one year for plants like parsnips to up to 10 years for plants like tomatoes. Exactly what storage life a particular plant has can be looked up in reference books, or perhaps found on the Internet. Some examples of common plants are peppers (3 years), sweet corn (3 years), other corn (5-10 years), and so on.

Storage times for a particular variety of plant seed are very dependant on good storage practices, and as such few commercial suppliers of seeds will guarantee their products beyond the year in which they were sold to you. Because germination rates for seeds will only decline with their age, most seed companies as a matter of good business practice and with the intention of providing the highest quality product to their customers will only sell seeds from the most recent year’s harvest.

What happens if you try to grow old or improperly stored seeds? The quality of seeds is measured by their germination rate. Older or improperly stored seeds will have a lower rate of germination, or may not germinate at all. If you are unsure about the quality of some seeds, nothing will be lost by just trying to plant them and seeing what happens. If they grow, the plants will likely be just as healthy as plants grown from fresh seed. If you want to test some seed for the ability to germinate, just set them in a few layers of paper towels and keep moist and in a warm place for about a week.

The most important things to keep in mind when storing seeds are to keep them dry, at a steady temperature and out of direct sunlight. Beyond this, a cooler temperature is better than a warmer one.

A good choice of location to store seeds is the refrigerator. You must insure they stay dry, and this can be done by first putting the seeds in a plastic or glass container.

For very long term storage of seeds, one of the best containers is a glass jar with a rubber seal. This is because all plastic containers will leak a little bit over time.

For long term storage of seeds they can be frozen. Before freezing seeds, you must ensure they are dry enough or the water inside of them will expand during freezing and damage the seeds. A rule of thumb is if a seeds breaks when you bend it, it is dry enough, otherwise it is still too moist. Freezing seeds can increase their shelf life up to 10 times what would otherwise be possible, for example tomato seeds can be stored up to 100 years, peppers 30 years, and so on.

One of the most common ways of drying seeds for long term storage is to use silica gel. There is a special type of silica gel with a color indicator, that is very useful to seed savers. The most common type available in the US is blue when dry, and changes to light pink as it absorbs moisture. Because this type of silica gel contains small amounts of cobalt, which is poisonous and a potential environmental contaminate, there are also other types available. In Europe the most common types are orange changing to blue, or orange changing to colorless. Color indicating silica gel can be reused over and over, by drying it out in an oven at about 125C (250F) for several hours until it reverts back to its original color.

To dry seeds with silica gel, place them together with an equal amount by weight of silica gel in a closed container. Let it sit for 7 days. Beans and other legumes should not be over dried or they may be damaged, so you may wish to dry these for only 5 days. If you suspect you have over dried a particular batch of seeds, you may wish to germination test the seeds to make sue they will still grow.

Information published on saving seeds can often be vague and contradictory. Of course all plants can be a little different, and it’s not often practical to discuss each one in detail. A number of books touch on the subject, and Suzanne Ashworth’s Seed to Seed is one of the best. In this article, I am going to try to give a brief introduction to some of the more important issues on the subject.

The home gardener has to take care that different varieties of the same plant don’t cross pollinate with each other. Exactly what will cross can sometimes be difficult to determine. For example, there are 4 different types of squash, none of which are genetically compatible and will not cross with each other. On the other hand, if you have Queen Ann’s Lace growing wild near your garden, it will easily cross pollinate with carrots you try to save seed from, because it is really a wild carrot.

The Latin name of a plant can often give you a clue. Plants with the same Latin name will almost always cross with one another.

Various techniques can be used to prevent plants from cross pollinating, and one of the easiest is to save seeds from an ‘inbreeding’ plant. Inbreeding plants are self pollinating, and generally don’t cross with neighbouring plants unless either special effort is made to force cross pollination or if insects cross pollinate the plants. Seed savers can usually save seeds from these plants without any special care. Examples of inbreeding plants are beans, peas, wheat and most other grains, tomatoes and peppers. These are some of the easiest plants to save seeds from, and in many cases what you harvest for seed is the same as what you harvest to eat.

Another way of preventing cross pollination is to only plant one of a particular type of plant at a time in your garden. It’s actually possible to plant more than one, as long as you insure that only one of them blooms at a time. For example it’s sometimes possible to grow two varieties of corn, one late and one early, and save seeds from both if they bloom at different times. It’s always possible to grow more than one type, and harvest all but one before any of them bloom.

If plants are separated by a sufficient distance, the pollen is unlikely to be able to travel from one plant to another. If you know what the safe isolation distance is for the particular type of plant you are trying to grow, it’s possible to grow more than one type separated by this distance.

Finally, there are a number of techniques to cage or cover plants to prevent pollen from travelling from one plant to the next, but still grow them side by side. I won’t get into this here.

What happens if plants cross pollinate when you try to save seed? It depends on the plant, but often the results are obvious. Since all plants traits are based on pairs of genes, half from each parent, if two very different plants cross pollinate, the results are likely to be very unique. In this case, you can simply discard the unwanted plant. In some cases, slow genetic contamination can occur over time, but this is less common.

Generally as a home gardener, if you use common sense, are as careful as possible, and accept small amounts of crossing as inevitable, you will be fine. Of course commercial seed producers have to be much more careful.

Beyond inbreeding and outbreeding, there is another classification that is important to seed savers: annuals and biennials. Annuals typically grow through the summer, and produce seed in the fall. Biennials require two complete growing seasons before they produce seed. In areas with hard winters, the plants often need to be dug up and brought inside during the winter. Example of biennials are cabbage and related ‘cole’ plants, celery, parsnips and carrots. Most vegetables are annuals.

While it’s not exactly saving seeds, many heirloom gardeners grow plants that reproduce by root division. Example of this are garlic, shallots, multiplier onions, and so on. Since there is no pollination with these plants, it’s not necessary to worry about genetic material spreading between plants. Because there is always the chance of small genetic variations, the process of roguing described below is very important to keep in mind.

Roguing is a very important issue for seed savers. Basically, this means ensuring you are only selecting seeds from the best plants possible. By selecting seeds from the best growing and most productive plants over a few years, you can develop your own seeds best suited to your own local growing environment.

It’s also important to save seeds from at least a few plants, if possible. This is because there are always small genetic differences from one plant to the next, and saving seeds from more than one plant will help preserve these beneficial differences.

As a rule, you should not save seeds from the same plants you eat from, and there are several reasons for this. Many plants will become inedible after going to seed. Often going to seed means the plants life cycle is complete, and it just dies. Otherwise, if you eat some part of the plant before it goes to seed, like the leaves or the first few seeds the plant produces, the plant has to expend energy replacing these, which means less resources will be available for strong and healthy seed production. If you do save seeds from the same plant you harvest for food, you should first save seeds, then harvest for food later.

Beyond keeping all of these things in mind, saving seeds is just as simple as letting plants first bloom, then collecting seeds from the seed pods that develop.

A future post will explain techniques of storing seeds.