Reinvigorating Old Seed

Some very old (yet valuable) cucumber seed

A recent issue with a cluster of old seed exhibiting poor germination led me to observe that, like Bill Gates stated, “Success is a lousy teacher”. In order for a gardener to improve his skills, he must be faced with failure and sometimes a lot of failure, though humbling, can be a great thing. Every failure that is recognized is a stepping stone on the road to success. That being said, just because I have identified 45 obstacles to growing tomatoes in my climate does not mean that I am not ignorant to the other 55 reasons why I cannot. The following information on reinvigorating old cucumber (or melon) seed is based solely on my experience with some very old melon seed. As my posts are not permanent, should anyone have any other helpful hints I would be happy to try them out and add them to this post.

The key to planting any seed is to first determine its percentage of germination. In an ideal world the germination of seed would not degrade over time, but - for various reasons - it does. The reason why a gardener would want to test germination before planting their seed is that germination testing enables the gardener to determine how dense to plant the seed. Seed with high germination rates requires less planting and more space between sowing while seed with very poor germination can require very dense sowing, resulting in the gardener seeing only 1% of the seed strong enough to become a seedling. My approach to germination testing utilizes a snack Ziploc bag and a paper towel. Once the seeds have germinated, I can then plant them where I want to grow. The only problem with planting the seeds I germinate is if I need to test germination of summer vegetable varieties in the winter.

Should you be in the position in which you have cucumber or melon seeds that do not germinate well, here are a few things you can do to. The majority of this information can be applied to working with other vegetable seeds.

1. Pre-sprout seeds as if you wanted to test germination.

This means placing the seeds in a controlled environment that is warm and moist. I like putting my whole “cucumber seeds in a moist paper towel in a snack-sized Ziploc bag” in my water heater closet. Controlling the environment helps ensure that each seed that can sprout is given every opportunity to do so.

2. Make sure that the sprouting medium (paper towel) is not too wet or too dry.

If the whole paper towel does not appear wet the seeds will not soak up enough water to sprout. Conversely, if I do not press out the excess water from the paper towel after moistening it then the majority of the seeds will most likely rot.

3. Remove anything that could rot or mold from the seed coating.

Even after properly fermenting cucumber seeds, seed growers sometimes do not clean all the old bits of fruit from the seed. I tend not to question why some companies leave miniscule bits of fruit on the seed, as the quality of a supplier’s seed is seldom related to the “stuff” left on the seed coating.

Dirty Seeds can mold, which can lead to poor spouting

Now the fleshy material is gone the seeds are ready to be sprouted.

4. Frequently check how the seeds are doing.

Once every day or two I check seeds that I am trying to sprout. This helps to check on possible problems as they arise.

 By diligent checking you may notice seeds sprouting (left) vs. nonviable seeds (right)

5. Remove all decaying seed.

As soon as I see a seed decaying I remove it. Seeds that are rotting will either drastically change color or will bloat up like a plump man who has outgrown his jacket. In this case, the plump inner seed portion has taken on water, which will decay the inside of the seed. If plump unviable seeds are left in the sprouting medium, the surface of the fleshy portion will decay until the fluids will pop out, spilling rotten sticky fluids onto the rest of the seed.

Notice the seed nearly popping out of its coat - like a plump man in a small coat

Another example of a nonviable seed that could pop open to rot the medium

6. Change the medium as often as necessary.

Should you choose a medium that is cheap and easy (such as paper towels) you can just throw it into the compost pile if it begins to produce a strange odor or change color. Changing the medium can help a few of the seeds that have not germinated yet to complete the sprouting process.

This bad example is for teaching purposes only! (=

If you forget to change your sprouting materials your seed will likely rot

7. Add a little bit of nitrogen-rich water-soluble fertilizer.

Sometimes a trace amount of nitrogen-rich fertilizer (such as Miracle Grow™) added to the sprouting area will help “wake up” some of the otherwise dormant old seeds. This does not always work and is not recommended for germination testing, but I have had a lot of success with adding a very miniscule amount of this kind of fertilizer to very old seed that needed some added help.

An ordinary water-soluble fertilizer (I normally never use this kind of thing)

I put just a very small pinch in (just a little more than on my finger tips)

8. For very old seed: Keep them in the controlled environment as long as possible.

Waiting until the seed coat is almost off is not necessary for vigorous seed, but with seed that is old and weak, ensuring that the seed is almost in seedling stage is highly important to ensuring that you can save this vegetable variety for the future.

Notice the seeds that have almost pushed off their seed coating (circled in blue).

9. Feed your seeds in a low concentration sucrose medium

Between when the seeds sprout and when they begin pushing off the seed coat, it is possible to feed them with a low concentration of sucrose in agar as mentioned in my last post.

10. Wait, wait, wait…

Seeds with low viability take a long time. Newly harvested seeds can sometimes fully sprout in under 12 hours while old seed can take over 20 days. Be patient. If the seed you are trying to grow was good but is now too old it may yet sprout.

Skilled gardeners store their most valuable seed carefully. Even if a gardener has thousands of seeds of a specific variety, storing a seed variety in poor condition can result in loss of the majority of the population. Though knowing how to bring old seed back to life is important, being able to avoid “babying” seed by properly harvesting, preparing and storing seed is much less work. By posting about my learning experience I hope each of us can better apply the words of Eleanor Roosevelt to our own gardening as she said, “Learn from the mistakes of others. You can’t live long enough to make them all yourself.”

Plant Breeding for the Home Gardener by Joseph Tychonievich

For those of you who would really not want to learn all the fine details of why vegetable breeding works or would just rather not read a really long book about vegetable breeding Plant Breeding for the HomeGardener by Joseph Tychonievich is just for you.

 

 

This book is great for those who do not want long reads.

One of the first things that I look for in a plant breeding book is if the author includes specific factors to select vegetables for when seed saving. In one chapter,  Tychonievich discusses selective traits for vegetables such as beans, cabbage, corn, lettuce, squash and tomatoes. The trait that most interested me in this chapter has to do with tomatoes. Tomato acidity and sweetness are noted as a few traits, along with an interesting trait known as umami. Umami, a meaty glutamate that tomatoes produce, is one of the things that make them so popular. I wonder if there is any simple method by which a gardener can test umami like you can test acidity and sweetness?

Though PlantBreeding for the Home Gardener is fun and easy to read,  it also contains some more advanced techniques and thoughts that are worth learning more about. In the chapter entitled “Beyond the Backyard – Advanced Techniques” Tychonievich references ideas such as polyploidy and embryo rescue.

Polyploidy refers to the genetic makeup of a specific plant. A diploid has 2 copies of genetic code while a tetraploid has 4 copies of a genetic code. Sometimes crosses between diploids and tetraploids are possible and sometimes they are not. As plants with different genes exhibit different growth patterns and flowering crossing diploids and tetraploids can sometimes result in very interesting (and sometimes more productive) results. However, crossing diploids and tetraploids can sometimes result in triploids, which are often sterile.

 

 

My garden is currently growing Jerico lettuce
which was bred for heat-tolerance and not for beauty!

 

Sometimes when making a cross between two similar species of plants the embryo of the seed aborts, or falls off the plant, before maturing. Gardeners can save the embryo of a difficult cross by a technique referred to as embryo rescue. According to Tychonievich, embryo rescue is “one of the most powerful techniques for getting new hybrids between species”. The method for rescuing an embryo requires the gardener to remove the seed embryo from the plant then place it in a substrate that enables the embryo to grow into a small plant, which can then be grown to seed. The substrate often consists of a gelling agent (such as agar), a small percentage of sucrose (to feed the embryo), specific salts (Murashige & Skoog (ms) basal salt mixture) that can be bought online. Tools and recipes for embryo rescue can be found online.

 

What interests me most about embryo rescue is not to apply this technology and methods to making new hybrids but in saving the rare seed that we already posses. Sometimes old seed has a very difficult time germinating and once it does germinate the growth of the seedling can be incredibly slow. If the gardener has very little seed and the seed is rare, it may be worth looking into embryo rescue as a means to provide nourishment to the seedling. Later stage embryo rescue techniques could be used with such seed to imbibe increased vigor by feeding weak seedlings until they at least push off their seed coating. In one online source, the research geneticist Sandra Reed notes that later stage embryo development could occur in a simple inorganic medium (agar) supplemented with 2-3% sucrose (powdered sugar).

In summary, Plant Breeding for the Home Gardener has something for everyone. The majority of this book contains ideas that are presented in a very straightforward manner while some of its more advanced concepts provide inspiration for further research and development by the lowly gardener.

Selecting Outcrossing Vegetables

Over time, I have contemplated the difficulty of saving seed from crossbreeding plants. Possessing limited space, the backyard gardener can find it difficult to grow the 100-200 plants required to avoid inbreeding depression in outbreeders such as carrots and corn. Even more difficult for the backyard gardener is the ability to select for specific traits in outbreeders, because backyard gardeners cannot start with 400 plants needed cull the plants down to a population of 200.

 

Purple carrots can exhibit a wide range of color variation

Carrot tops before selection

Carrot tops compared with the other plants in the garden

With these challenges in mind, it is a wonder that vegetable gardeners can improve on any outcrossing vegetable variety. Having a knowledge of what characteristics can be selected and how to select for these traits will enable gardeners from any climate to select vegetables for the attributes that best suit their needs.

Cutting Carrot tops to keep stecklings from transpiring

Composting all these carrot tops felt a bit like a waste

It can be difficult to breed out the dominant white color

My experience saving carrot seeds started a few years ago when I saved some seed of Purple Dragon in my summer garden. The results were fairly good but I had difficulty selecting for the dark purple color that I wanted in the roots because I didn’t know gardeners could select for color in carrots by making stecklings, as shown in The Organic Seed Grower.

A few of the many purple carrots I pulled from the garden.

Stecklings are carrots (or another root crop) that has the majority of its top cut off (to keep from transpiration) and is prepared in a specific way for either winter storage, selection, or both. The great thing about carrot stecklings is that the gardener can cut the bottom of the carrot off to evaluate color, texture and taste. When returned to the garden, healthy stecklings will keep growing and produce seed.

A large bucket full of purple carrots

Sorting Stecklings for Desireable Traits

 

 

Though the color of this individual carrot was good, it contracted CMV

 

Culled carrots end up on the dinner table with asparagus

Another technique I recently taken advantage of was to cluster my stecklings so that I can select seed from the best plants. Though I am still growing out 200+ carrots, I am only saving seed of the best 50 plants. By doing this, I am maintaining genetic diversity (utilizing the total population of 200 plants) while still selecting the carrots that exhibit the most desirable features (dark purple color). The more traits a gardener selects for, the more unwanted plants he/she will need to remove from the population, so it is a good idea to only select for a few traits each time the gardener saves seeds.

Saving seed from the 50 best plants still maintains genetic diversity.

Best Carrots were planted in the middle with the good seed surrounding them.

I often feel fortunate that my mother-in-law is able to travel abroad and speak so many languages. I owe her a great deal of thanks for finding these purple carrot seeds for me during her travels.

A little tight, but these carrots will still produce seed.

The stecklings begin to sprout.

The point of this post is to emphasize to others that, even with limited space, backyard gardeners can use selection to produce more desirable vegetables – as long as they know how.

Even gardeners with limited space can select great carrots.

Kyoto Red Carrots

One of the reasons why I love to trial vegetables is because I occasionally encounter a vegetable variety that excels in many of the qualities I am looking for. From my experience this last year growing a new red carrot variety I would have to say that Kyoto Red is one of the very best carrots I have ever tasted.

The Kyoto Red Carrot

Though last year’s carrot trials did not go very well, they gave me the opportunity to find something much better than I have ever grown before. I planted seeds of Kyoto Red in the kids’ garden, knowing that I would not be saving seed of this variety this year.

 

 

Kids' Garden in Late October

 

 

Kids' Garden in December




Kyoto Red Carrot Leaves in December

 

During the time period in which my carrots were growing (late October-late February) the kids’ garden received full sun, howbeit much less than they would in the summer. I was told by a staff member at Kitazawa seed that red carrots tend to produce more dark colors during when grown over a cool season.

 

 

Fresh out of the Garden

 

So why should anyone even grow a red carrot? What makes these carrot superior to varieties you may grow already? My response is that the Kyoto red carrots have a wonderfully smooth texture and smooth surface. For those of you who feel that food texture is important, this might be worth noting. Second, these carrots are sweet. This does not mean that they are sugary sweet – but they are pretty sweet when they are young and have a nice sweet aftertaste as they get larger. Third, they produce a lot of food for the space. The roots are deep, and for those with a deep garden bed and limited space these carrots produce plenty of food for the space. Lastly, these carrots are red. The red color tends to consistent throughout so that the few carrots that seem lighter colored still exhibit a moderately dark red flesh.

 

 

Interior view of the Kyoto Red Carrot.

 




A view of what they look like when sliced.



Color comparison - sorry no samples available. (=

 

 

When taken as a whole, the Kyoto red carrot is a very smooth, sweet and colorful carrot. This carrot variety would be great to sell at any farmers market – if you don’t eat it before then!

 

I was thinking of taking these to the market ---- but we ate them instead. (=