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Saving Tomato Seeds

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.

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Storing Seeds

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.

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Saving Seeds

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.

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Very Basic Genetics

When Greger Mendel did research on pea plants in the 1860’s, he identified a number of concepts that are important to heirloom plant growers, and people wishing to develop their own plant varieties.

His research centered around the concept of pairs of genes. He said all genetic traits were determined by these pairs of genes, and the genes within these pairs were inherited, one from each parent.

If, for example, you had two parents one with gene pair AB and another with gene pair CD, there were 4 possible outcomes for their offspring all with equal statistic probability:

AB x CD
=======
AC . AD
BC . BD

The order of the genes is not important, in other words AC is identical to CA.

Mendel’s research focused on several traits of pea plants, but for the purposes of this blog post we will look at the height of the plant. He noticed two distinct type of pea plants, those which grew tall and those which were short.

Before experimenting with cross pollinating, Mendel developed varieties of plants that only produced the traits he was interested in, in this case the height of the plant. He did this by discarding plants with the unwanted traits, and growing successive generations until the unwanted traits no longer appeared. This is a process called roguing, and it insured he was working with a gene pool that no longer contained the unwanted traits.

In this way he was able to determine that the tall plants has a pair of identical genes which made them tall, and the short plants had a pair of identical genes that made them short. For the purposes of his research, he referred to the tall gene as T, and the short gene as t.

He then took one of each type, cross pollinated them, and produced offspring as follows:

TT x tt
======= . (F1 Hybrid)
Tt . Tt
Tt . Tt

He referred to this generation as an F1 Hybrid. What he observed was that all of the resulting offspring were identical and all were tall. He explained this by saying the tall gene was dominate, and when it was present with a recessive short gene, the plant was always tall. He knew the genetic makeup of each of the plants was identical, with one of each type of gene, because they had to be inherited from parents which he had previously determined to have pairs of identical genes.

He then took pairs of plants from this generation, and crossed them again to create an F2 Hybrid as follows:

Tt x Tt
======= . (F2 Hybrid)
TT . Tt
Tt . tt

What he observed was that 75% of the resulting offspring was tall, and 25% was short. He said this was because only plants with the gene pair tt could produce short plants, otherwise as long as at least one dominate T gene was present, the resulting plant would be tall.

It was not sensible to talk about successive generations of hybrids (F3, F4, etc), because the genetic composition of the tall parents could no longer be determined, they could either be TT or Tt. This is referred to as genetically instability.

He said if it was desired to produce short plants from a genetically unstable variety, you simply needed to select 2 short plants and the resulting offspring would be short. Since then the T gene would no longer be present in the gene pool, all future offspring would also be short and the variety would be genetically stable.

He said if it was desired to produce tall plants from a genetically unstable variety, it was necessary to produce a number of successive generations of offspring and rogue out the short plants. In this way the t genes are gradually removed from the gene pool, and eventually only the T genes would remain, and the variety would become tall and genetically stable.

This turns out to be somewhat of a simplification of a much more complicated process in nature, nevertheless the basic principles here always hold true. In nature some traits are determined by more than one pair of genes, some traits are sex linked, in some pairs of genes one of them is not completely dominant, and so on. This example with pea plants deals with only one pair of genes, and since one particular plant can have hundreds or thousands of pairs of genes producing their own individual traits, a very complex situation can develop when cross pollinating two different plant varieties.

If you are trying to produce a new variety of plant through cross pollination, the basic idea is that you start by selecting two plants with traits you would like to see combined. In the first (F1) generation all the plants will always be identical, and will be an indication of the sort of plant you can hope to develop during the process of genetic stabilisation. During the stabilisation process, you rogue out plants with undesirable traits, and in the end you have a new stable variety. The stabilisation process usually ranges from a few up to 10 years.

Even if as a gardener you are not interested in in developing new strains of plants through cross pollinating, it’s still important to understand the concept of gene pools and roguing. Plants evolve by means of chance genetic variations, and you always want to preserve desirable new traits and rogue undesirable traits as they appear. You always want to select seeds from the best growing and tasting plants in your garden, to insure any genes associated with these traits are preserved. You should never save seeds from plants that bolt (go to seed) prematurely or otherwise don’t develop properly, or you risk preserving these traits.

For more information on Mendel’s work on pea and other plants, see:

http://www.visionlearning.com/library/module_viewer.php?c3=1&mid=129&l=

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Heirloom Gardening

Exactly what an heirloom plant is can mean different things to different people. Purists will say a variety can be no younger than 60 years old, because that would ensure its origins are from before WWII, when modern agriculture emerged and varieties began to be patented. At the very least, an heirloom variety is one that is free from patents and intellectual property rights, non-genetically manipulated and not a hybrid variety. It is always possible to save the seeds from heirloom plants, and use them to grow an identical plant. In other words, you must be able to both legally and practically save them from one year to the next and pass these seeds onto your children like an heirloom. Since new varieties can be produced today but using traditional techniques, many people refer to these as modern heirloom varieties and consider them just as special as the older original heirloom varieties.

Before WWII if you wanted for example, to grow a cucumber, chances are what you would do is ask around and find someone who was growing a nice tasting cucumber and get some seeds from them. You could then save some seeds from your plants, and share them with others. If you were looking for something special and couldn’t find it anywhere else, you might create it yourself by taking two different cucumbers and cross pollinating them, thus creating a new heirloom variety.

Nowadays, if you want to grow a cucumber, chances are you would go to a garden center and buy a package of cucumber seeds. Odds are that the seeds you buy will be both patented and a hybrid variety, because these are more profitable for seed companies to sell as they can control the distribution of them. It may be that you grow excellent cucumbers with these seeds, so why should you care if they are an heirloom variety or not?

Hybrid varieties are made by combining the genetic material from two plants in a laboratory or factory, and the seeds produced by these plants are not genetically stable. In general, if you save the seeds from these plants and replant them, they will tend to revert closer to one of their original parent plants with each successive generation. Seed companies are generally able to keep the identities of the parent plants a secret, and so it is not possible for a competitor or home gardener to exactly copy the process of producing the seeds.

Let’s have a look at some of the reasons why many home gardeners choose to grow commercial seeds.

Seed companies are very adept at marketing their products and making empty claims that their F1 hybrids (common hybrids) are inherently higher quality. Often seed companies claim better taste, disease resistance or improved yields in a wider variety of climates. Much of the marketing warns you not to take a chance. You are going to spend all summer toiling in your garden, so don’t risk growing anything else.

It is true that every variety of plant, F1 hybrids included, can have unique or desirable characteristics. It’s not always true that hybrids are the only varieties with these characteristics or that heirloom varieties don’t have their own special qualities that you can’t find in hybrids. In reality, most of the characteristics seed companies are looking for in a variety have to do with long storage, ease of shipping, uniform appearance of the fruit, and so on. These characteristics are rarely interesting for the home gardener, and frequently don’t include tasting good, despite what their marketing says.

In some parts of the world heirloom varieties of plants are illegal. For example in Europe there was the 1945 treaty of Paris, which has evolved into to the current Common Agricultural Policy (CAP). The secret of the success of the CAP lies in it’s obscurity, and few people really understand how it works or what it does, and so it simply goes unchallenged. A very important part of how it functions lies in allowed seed lists. Each country maintains it’s own lists of varieties of seeds that are allowed to be used for food production and seeds to be sold to home gardeners. In theory, the purpose of these lists are to provide ‘genetically pure’ food, that has been tested for safety. Initially, it was these lists that saved Europe from genetically modified (GM) varieties, because they simply weren’t on the lists yet. In practice, the procedure for adding and taking seeds off these lists is very political. Very few heirloom varieties are on these lists, and the very fact these lists exist all but rules out the possibility of someone developing a new variety and selling it, unless you are a powerful food company. There is no credible testing for safety when adding new varieties, and there are virtually no known safety issues that they would be testing for anyway. Virtually all of the varieties on these lists are patented and the majority are hybrids. The purpose of these lists are to protect patent holders from ‘unfair competition’ from unpateneted varieties.

Most people don’t realize the huge number of heirloom varieties available, or just how special and exciting they are. For example, there are about 4000 different kinds of known tomatoes, of which about 1000 are thought to be ‘interesting’. It’s true many of them are red, but there are also yellow, green, white and purple ones. There are striped tomatoes, and tomatoes that grow hollow so you can stuff them. Some are as small as a pea, and some grow to more than 2Kg. They all taste a little different, and most are really delicious. You will never look at a store bought tomato in the same way again, after you have had one of these. It’s the same for virtually all kinds of fruits and vegetables, there are an unbelievable number of different varieties to choose from. There is particular interest now in so called ‘antique apples’. You will never want to eat an apple from the store again, after you have tasted an antique apple, they are so unbelievably good.

Okay, I hear you say, you still aren’t convinced. If you want some excuses for not growing heirlooms, here are some common ones. You want the convenience of going to the garden store and buying a package of seeds. You aren’t going to save the seeds anyway, so you don’t care if they are patented or hybrid. There is a particular trait in some hybrid variety that you want, you think it tastes good, you know it will grow in your garden and you don’t want to take a chance or go to the hassle of locating or buying an heirloom variety. You certainly don’t want to grow anything weird. So what? What does it matter? What does a package of seeds cost anyway?

The sad fact is that large seed and food companies are winning, and most people are using these excuses. So successful are these companies in fact, that by some estimates 70% of the varieties grown before WWII don’t exist anymore. They are gone and will never come back. More are disappearing every year. They are gone simply because no one bothered to grow them in their garden and keep the seeds from one year to the next. They are gone because the companies that sold these varieties couldn’t compete with the convenience of being able to go to the garden center and buy a package of commercial seeds. This is our genetic heritage, that fed many generations of our ancestors. It represents centuries of home gardeners and farmers creating varieties that tasted good to them, and they wanted to eat. It’s as much a catastrophe as losing the world’s rainforests, and the species contained within them, and few people realize it’s happening. By hunting out heirloom varieties, saving and trading seeds with others, you can do your part in saving the genetic resources we have left.