Seed Saving

An Introduction for the Food Gardener

by SCMG Stephanie Wrightson

While I have saved herb seeds for culinary purposes, my only personal experience with vegetable seed saving for propagation involved a winter cover crop of fava beans which had an obvious and easy seed to save. My training touched briefly on the subject but I found myself turning to other experts to answer the detailed questions put to me during my Sonoma County Master Gardener activities. Therefore, I made it a point to attend a recent seed saving workshop held at Harvest for the Hungry in Santa Rosa. It was presented by Yeti Seed (yes, that is his name), a member of the West County Community Seed Exchange.

Yeti explained that a hybrid results from the cross of two plants. This is not a seed you can save and expect the same variety the second year because the seed will revert to a dominant variety. If your favorite tomato is the hybrid ‘Early Girl’ or ‘Better Boy,’ you will have to buy transplants or seeds each year. You can save seed from ‘Early Girl’ but you will get a red tomato that is not an ‘Early Girl.’ Yeti also explained that heirlooms are open-pollinated. If you save the seed of a ‘Green Zebra’ or ‘Brandywine’ heirloom tomato, then that is what you are going to get when you germinate it. At one time, heirlooms were varieties that were not in the commercial realm; their seeds were saved and handed down through families.

Why save seed when hybrid and heirloom seeds are easy to purchase? In Yeti’s opinion, a true heirloom should be locally adapted. If you save seed, you will select plants that have adapted best to your climate, soil and gardening idiosyncrasies (e.g., watering a lot or a little, etc.). Over time, you will develop the very best performing vegetables for your garden as well as the best-tasting to your palate. Plus, the date stamped on a commercial seed package only means that the requisite percentage of seed germinated that year. You do not know the actual age (and future viability) of the commercial seed. With your own saved seed, you have an extended period of viability with most vegetable families.

It is helpful to know what family a vegetable is in because seed saving for vegetables within the same family is similar. Yeti provided a list of nine major vegetable families and examples of vegetables included in each. Some seeds are easier to save than others. For example, seed saving from the Brassicaceae family is difficult because the species within this family (broccoli, cabbage, cauliflower, etc.) often cross pollinate. He suggested that individuals new to seed saving start with some of the easier plants such as tomatoes, beans, onions and lettuce. They are in the following families:
   Solanaceae           tomato, potato, pepper
   Leguminosae           beans, peas, peanuts
   Amarylliadaceous           onion, leek, garlic
   Compositae           lettuce, sunflower, endive

Selection of the specific plant(s) for seed saving is crucial. In general, you should select the nicest fruit or seed heads. For example, when you select the lettuce that bolts (goes to seed) late in the season, that is the positive trait that you are trying to perpetuate. If you plan to save seed, you may want to grow additional plants so that you can have some to consume as well as some to save for seed. Tomatoes are a bit of an exception in that you can consume the pulp after you remove the seeds. Whereas, once some plants set seed, their food is no longer available or palatable.

To ensure the highest germination rate of seeds, the plant should be fully mature. This means that you would not take seed from a green pepper which is the immature stage of a pepper; nor would you collect dill seed when the plant is in the early stages of flowering and still green. And, while you may have some germination percentage with some plants before they are fully mature, the rate will be low and the storage capacity of the seed will be reduced.

Some gardeners state that they have success with letting some tomatoes over-ripen, fall to the ground, and self-germinate in the spring. For most gardeners, this is too uncontrolled. If you have many varieties, you may not know what is coming up or when to expect it to mature, and it may not have been a fruit from the best plant specimen. Nor do you control specifically where the plant will put down roots. Some seeds require a process to become viable like tomatoes: the conditions (temperature, rain, etc.) must be right to allow some fermenting to occur to dissolve the outer gelatinous covering and, then, to encourage germination and sprouting after the last frost date in the county the following year. By seed saving, you are dictating the right plant in the right place at the right time.

While some seeds may be put through a simple controlled fermenting stage like tomatoes and cucumbers, other plants like basil and dill may be allowed to die (i.e., turn brown) in the garden before harvesting. It is important that you harvest before seed drops or, in some cases, eject themselves from their pods. This is where a seed saving reference can be invaluable. Yeti recommended “Seed to Seed” by Suzanne Ashworth. It is an encyclopedic presentation of about 160 vegetables (including a few grains and herbs) and how to grow them from seed. Especially important for seed savers are descriptions of how each vegetable is pollinated, how seeds develop, how to harvest and store seed and germination rates.

Seeds left to dry on the stems of the dead plants often go through a threshing and winnowing process. Yeti uses a series of various sized stainless steel screens and bowls. The larger threshing screens catch the stems, pods and other large debris and allow the seeds to fall through into a bowl below. But there are other smaller particles and dust that must be removed. The winnowing process involves smaller screens that allow the tiny particles to fall through to the bowl below but not the seed.

In some cases, the drying process will be particular to the area in which you live. For example, some people can extract dried pepper seeds after allowing a mature pepper to dry in its entirety. However, in a moister climate, such as near the coast, you might open the pepper to find moldy (not viable) seed. In this case, Yeti cores around the stem and removes the stem and seeds from the pepper before allowing the seed to naturally dry. Never use your oven to dry seeds!

Always label your seeds and label again if they move to a new container in the seed fermenting, drying and/or saving process. Too many seeds look similar. It is important that saved seed be dry before packaging. Excess moisture will cause seeds to rot. Yeti uses small “coin” envelopes he purchased at a stationary store. These envelopes are labeled (species, variety and date) and placed in airtight glass jars – also labeled. Storage should be cool and dry. A refrigerator suffices in most cases. Yeti stated that properly saved and stored tomato seeds, for example, can be viable for 10 to 12 years – and, in some cases, as long as 20 years!

Am I likely to become an avid seed saver of every plant I grow in my food garden? Probably not. Gardening in a community garden means that I cannot completely control cross-pollination where certain vegetable families are susceptible. But for that favorite tomato – I’ll do it!

Saving Tomato Seeds

The method below is one viable process presented in a workshop I attended. The workshop leader jokingly referred to the method as “squeeze it out and let it rot.” Check written seed-saving guides for more detail and other seed saving processes for vegetables, grains and herbs.

Select a mature or over-mature fruit from at least three to four separate tomato plants of the same variety that were good specimen (the more, the better to maintain diversity). Note that open pollinated plants are very close, but not identical. Therefore, if some plants in a variety matured sooner and others later, you are likely to ensure a longer harvest by selecting seeds from a number of plants.
Slice the tomato in half across the middle (not from the stem down).
Squeeze slightly and using a spoon or knife, scrape the seeds of the same variety into a bowl (use the remaining pulp for tomato sauce or in another recipe).
Pour the seeds into an open glass jar and label (separate jar for each variety). The seeds and juice might fill the bottom one-fifth or one-fourth of the jar.
Set the jar in a warm indoor place to ferment – not in an oven or in the hot sun (the speaker found that the top of his refrigerator provided this environment). Most seed saving books suggest a 5-day fermenting period, but the workshop speaker said that because Sonoma County has colder nights, a 6- or 7-day fermenting period may be required to remove the gelatinous covering around the seed and to see a thin mold on top of the tomato seed mixture.
After the fermenting period is finished, add water (to approximately double the volume in the jar). What floats to the top is the scum and immature seeds. Carefully pour this off. Mature seed sinks to the bottom.
Repeat step 6 being careful to retain as much mature seed as possible in the jar.
Put remaining seeds into a mesh strainer. Rub the outside bottom of the strainer with a clean, dry towel. This will remove most of the moisture.
Spread the seed on a plate and label it. Do not use paper plates or towels as it will stick. [One attendee stated that he uses wax paper and the slight use of a spatula to remove dried seed – he labels the drying seed by writing on the piece of wax paper. Another attendee said that she uses a paper towel and, when the seeds dry and stick to the paper, rolls up the paper towel, labels it and stores it in a cool, dry place. The following spring, she lays the paper on a growing medium and sprinkles an appropriate depth of dirt on top and proceeds to germinate her plants.]
Place dried seeds in labeled envelopes. Place the envelopes in sealed glass jars and store in the refrigerator.