Saving for the Future: Seed Saving Tricks and Tips

As summer winds down and the summer crops and flowers start to slow down many gardeners start thinking about saving seeds. Who doesn’t love saving seeds from that favorite tomato or beautiful coneflower?  Not only do you have some for next year, but you can also share with your friends! There are definitely some things to consider and some myths out there when it comes to seed saving, so let’s talk about how to do it right. 

You’ll get the most consistent results from open pollinated or heirloom varieties that are self-pollinating.  These plants have genetics stable enough that the seeds you save will come out looking and acting like a close approximation to the plants from the previous season (with some variation based on your selection of the “best” plants you save seeds from. Self-pollinating species are: tomatoes, peppers, eggplant, beans, peas, peanuts (note, peppers and eggplants have more open floral structures that can be cross pollinated).  Most tree fruits like apples and pears are cross pollinated and they are notorious for not “breeding true” – even if you hand pollinate to ensure that the mother and father are both the same cultivar you’re likely to get surprises.  Stone fruits (peaches, plums, etc) are less variable but still not true-breeding.  Bee pollinated plants are also notoriously hard to save seed from, since they can cross pollinate with different varieties and cultivars from miles away.  It is especially interesting for plants that look totally different but are the same species (like pumpkin and zucchini).

A puccini – or a zumpkin? Either way, it was nasty.

Myth: You can’t save seeds from those new modified hybrid plants. They’ve been made to be sterile

First off, hybrids aren’t genetically engineered and there are no GE plants available to home gardeners (most home garden crops don’t even have GE versions).  Hybrid plants do in fact usually produce viable seeds.  However, you won’t get the consistent results you will with open pollinated/hybrid varieties.  Hybrids are the F1 generation of a specific cross between a mother and father plant.  The offspring from that F1 generation (the plants from the seeds you save) is called the F2 generation will be a mix of traits – some will look like the F1 generation, some will look like the mother, some the father, and some the milkman.  So you’ll be in for a mixed bag of surprises.  According to our former GP colleague Joseph Tychonievich’s book “Plant Breeding for Home Gardeners” you can even develop a stable open pollinated variety from hybrids by saving seeds over a few seasons, selecting seeds from the plants that most resemble the cultivar you’re trying to save. 

You’ll want to make sure that the fruit/flower head that you’re saving seed from is mature.  This can be tricky for some vegetables, because we eat them in their immature states.  Peppers need to change from green to whatever their color is (red, yellow, orange, purple, etc),  cucumbers and zucchini (and other squash) need to turn into those massive, bloated fruits that often change to yellow or orange.  Beans often need to change to yellow or tan (and may have stripes).  For flowers, the seed heads or fruiting structures often need to turn brown and dry or start to open. 

If the weather cooperates, you’ll want to collect seeds from dry fruits/structured (beans, some flowers, etc) before significant rainfall so that seeds don’t become wet and potentially mold or break dormancy.  Collect seeds and place in a warm, dry location to let them continue drying out (if they’re small you want to put them somewhere they won’t blow away).  After drying, store seeds in envelopes or containers and put them in a cool dry place.  I often tell people to store seeds in the freezer – the cold temperature slows down respiration in the seeds and can extend their lifespan (the fridge is too moist/humid).  If you do that, drop your envelopes or containers down into a sealable container or bag to help keep condensation minimal when you pull them out of the freezer next year.

For home gardeners, it may not matter that you get plants next year that exactly copy the ones you saved seeds from – the fun can be in the surprise.  Who knows, you may discover a new variety – at least one that is exciting to you.  It can be fun seeing the variation in your new plants and finding something that you love. 

Epilogue: A special case – tomatoes

Most of the vegetable crops we grow don’t need any special treatment to break their dormancy (you’ll have to research flowers on a case-by-case basis) – save the seed and plant it next year and it will pop up.  Tomatoes are a bit of a special case.  If you scrape the seeds out of the fruit you’ll notice they’re still covered with the “goo” from inside the tomato which is called interlocular fluid (interlocular = between seeds).  The coating persists on the seed even if you wash them.  It has long been held that this coating retains some of the hormones of the fruit (like abscisic acid) that inhibits germination (though not all experts agree). So many sources will tell you to go through some process to break down the coating left on the seed, most commonly by placing the seeds and associated goo in a container, adding a bit of water, and letting them ferment for a few days.  You can dump them out and wash off all the gunk. Whether or not this is required to break dormancy is up for debate, but it does provide you with clean seeds that you can store easily.  There is also some evidence to suggest that this fermentation process helps remove pathogens on the exterior of the seed (heat treatment can help remove interior pathogens as well).

Some people just scoop out the seeds and smear the goo on a paper towel and try to scrape them off next year.  Some people add the step of washing, but this will still not remove all of the goo coating the seeds. This works if you’re not trying to share (or sell seeds) since they will stick to the paper towel. My guess is that the in the day or so that it takes for the goo to dry there is enough fermentation or decomposition going on to break dormancy.  If you don’t want the seeds stuck to a paper towel, you can use wax paper or some other non-binding surface, but you’ll still have dried goo on your seeds.

Sex and the Single Squash: A study in plant sex, sexuality, reproduction, and seed saving

In the 1960s, author and future Cosmopolitan magazine Editor Helen Gurley Brown scandalized the country with her book about independent single women called “Sex and the Single Girl.”  Taking a page from Ms. Brown, we can have a discussion about “Sex and the Single Squash.”  Here, we can talk about plant floral structure and reproduction and its effect on fruit production and even seed saving.  A true discussion of the “birds and the bees” if you will. This is especially important in the vegetable and fruit realm, since reproduction is why we get tomatoes, peppers, apples, plums and such in the first place.  It also is important for producing seeds, as those arise from the reproductive process as well.

Whether you knew it or not, flowers are not just different in appearance from plant to plant, but the ways in which they are pollinated and turn into fruit are different as well.

Some plants have what are called “perfect” flowers where both male and female parts are present, such as roses, apples and dandelions. In a way of speaking, you could say that these flowers are hermaphroditic.  These flowers may or may not be self-pollinated.  Depending on species genetics, some plants can self-fertilize (like tomatoes and beans) and others require cross-pollination (like apples).

Other flowers are “incomplete,” meaning that they have separate male and female flowers.  Some plants with “incomplete” flowers are called dioecious (Greek, meaning “two households”), and have distinct male and female plants such as ginkgo trees, holly bushes and kiwi vines. Some “incomplete” plants are monoecious and have distinct but separate male and female flowers on one plant — like squash, cucumbers and corn.

So, here’s where the vegetable garden comes in — one of the questions that I get every year without fail has something to do with why most of the flowers on a squash or cucumber or other cucurbit (that’s what we call plants in this family) plant do not produce fruit.

There are a few explanations – high heat causing aborted flowers or fruits or improper pollination, absence of pollinators, or, most likely, the fact that some of those flowers were never going to set fruit because they were male.  In answer, I have to explain that about half or more of the flowers on the plant are male and are, unfortunately, anatomically incapable of producing fruit.

There are a few ways to tell male and female flowers apart when it comes to members of the cucurbit family.

First, look at the base of the flower. If the base is swollen and looks like it is a tiny version of the mature fruit, then it is a female flower.

If the base is just a straight stem (in flowers, this stem is called a peduncle), then it is a male flower.

The second method is to look inside the flower. If there is one large central structure, called the pistil, that indicates the flower is female.

Male flowers will have several, smaller stamens inside. Female flowers also tend to be larger than male flowers.

Image result for squash flower male female

In the world of the single, available female squash blossom, life revolves around attracting honey and other native bees that have also recently visited male flowers to assure pollen transfer.

All members of the cucurbit family require this pollination tango to make sure that the female flowers produce fruit.

Each species and even variety of squash have a different ratio of male to female flowers. The ratio is usually about 1-to-1, but it is not unusual to see varieties with many more males than females.

Many of the plants also produce an abundance of male flowers early in the season, sort of as a teaser to make sure bees are attracted to the plant later on to pollinate the female plants.

So if a majority of flowers die early in the season without setting fruit, or about half of the flowers die throughout the season, there is nothing to worry about.

If female flowers are dying throughout the season without producing fruit, though, there is a definite problem. This means that there are no bees available to pollinate the plants.

If fruits have shrunken parts or misshapen, then there could be an issue of incomplete pollination from not having bees around. This could result from not having enough food for them in the area to encourage their presence, or from weather being too cool or wet for bees to get out and pollinate.

The lack of bees could also be the result of improper use of pesticides in the area.

If it seems like the birds and the bees aren’t happening in your garden, there are ways that you can ensure fruitfulness by taking matters into your own hands.

Transferring pollen from male flowers to female flowers can be accomplished using a small artist’s paintbrush or by simply pulling off a male flower and using it to apply pollen directly.

Gardeners who want to save seeds from plants in this family should also pollinate flowers by hand, and actually go so far as to protect the female flower from outside pollen using some sort of cover.

In fact, this method is often used by plant breeders or those who want to save seeds of crops that easily cross-pollinate.  Hand pollination followed by bagging the flower to keep pollen or pollinators away to avoid accidental unwanted pollen is often used to produce.

Believe it or not, several members of the squash family that look or taste nothing alike are the same species and can cross-pollinate. For example: Zucchini, summer squash, pumpkins, scallop squash, decorative gourds and acorn squash are all in the species Cucurbita pepo and can cross with each other.

A few years ago, one of my Master Gardeners came up to me at the end of a meeting and asked me what was wrong with her zucchini. She handed me an object roughly the shape of a zucchini, only a bit larger and splotched with orange. She had saved the seeds from the year before.20151104_200712

I immediately answered that her zucchini had crossed with a pumpkin. Both of these plants are the same species and can easily cross pollinate. Even if you don’t have pumpkins in your garden, bees can travel 2 miles or more in search of food.  So she was left with what I would call a Puccini.

Easy cross-pollination of varieties is why the most common heirloom crop varieties you’ll find are tomatoes and beans. Both of these crops have closed flowers that help resist cross-pollination.

They are most likely to be self-fertile, meaning that the flower will pollinate itself without outside assistance. This helps the plant breed true — so next year you end up with something that’s roughly the same as what you had this year. These plants can be just a few feet away from a different variety and they will not cross pollinate.

If you want to save something that is bee-pollinated, like your squash, pumpkins or cucumbers, you might want to do the brush and bag technique. Otherwise you might end up with a surprise in the garden next year.

The heirloom varieties that we often save are open pollinated, meaning that when they cross with themselves their genetics are relatively stable and you won’t see a lot of difference from year to year. (There will still be some difference, so if you save seeds for a long time you can end up with your own strain of a variety suited to your garden and location.)

Hybrids, on the other hand, have less stable genetics than the open pollinated varieties. With the way genetics work, some of those offspring will have traits of the mother plant, some will favor the father and some will be similar to the plant you are trying to save (and some might look like the milkman).

When seed companies sell hybrid varieties, they have to maintain a population of the mother plant and father plant to cross them every year to get the specific hybrid variety.

While the results of saving seeds from hybrids will be unpredictable, it can also be fun. My friend, plant breeder Joseph Tychonievich, points out in his talks and his book, “Plant Breeding for the Home Gardener,” that you can save the seeds from plants most closely resembling the desired plant over several years.

Just keep planting your selected seeds and harvesting the closest one to what you want. After about three or four years, you can end up with a relatively stable, perhaps even open-pollinated variety, that is your very own based on that hybrid variety you love.

And if you end up with a cross-pollination, either purposeful or accidental, you won’t see a difference in the fruit from this growing season (except maybe in corn, but that’s another story)  Those changes won’t be apparent until you grow out the seeds you saved.  So you won’t know until next year if you have one of those pucchinis.

And don’t forget: If you do have an overabundance of male squash flowers, they are edible too. You can put them in a casserole, fry them, stuff them, and more.