The garden's self-reproduction: saving seeds for an autonomous garden

Saving seeds is not essential but is certainly critical in order to reduce operation costs and increase autonomy. It’s also a guaranteed source of organic seeds! Like harvesting, it may be obvious how to collect the seeds of some crops, while other crops will leave one clueless. Here are some info, methods and tips to harvest seeds from the most commonly grown crops in our gardens.

Rules of thumb:

1. Most root crops are biennial and need to be stored indoors over the winter, or under a thick layer of mulch and other protection if kept in the garden. It’s nearly impossible to keep biennial and perennial plants alive throughout the winter in containers, as the roots usually freeze completely and die.

2. Most brassicas seeds are collected the same way.

3. Do not harvest seeds from diseased plants, seed heads or fruits.

4. The blender method for fruits goes as follow:

• Put the fruits (halved) with water in a blender (about 25% fruit an 75% water). Blend well at low speed, until the seeds are separated from the pulp. Let sit.
• Viable seeds will sink to the bottom, while debris and bad seeds will float.  Stir gently the floating pulp to allow good seeds that got trapped to sink to the bottom.  
• Fill gently with water to the top and flush out some water with the pulp that follows. 
• When good seeds are starting to move with the water, re-fill and re-flush. 
• Repeat until all the pulp has been removed and only good seeds remain. One can also use a net to catch some of the pulp at the beginning, in order to speed up the process (and use less water).
• Pour the water+seeds into a fine strainer. Set on a towel to remove excess water, and lay out on a hard non-porous surface to dry, in a single layer. Use your fingers to separate clumps of seeds if any. Small seeds generally dry quickly.

Types of plants :

-Annuals (A) produce seeds the same year as they come to maturity. They usually die after producing seeds. Some plants which are not annual are treated as such under a cold climate like ours.

-Biennials (B) come to maturity on their first year and produce seeds on their second year of life. They must be protected during winter either by covering them or bringing them inside and planting them back outside in spring.

-Perennials (P) produce seeds every year, but never die after producing them. Some perennials rarely or never produce seeds when grown in a garden; they most often need to be propagated by root cuttings.

-Self-pollinated (s-p): Some plants do not need the help of pollinators in order to pollinate their flowers and produce viable fruits and seeds. Each flower contains both a "male" (anthers) and "female" (ovaries) parts, so the pollen doesn’t need to be transferred between flowers. This limits the risks of cross-pollination (when the pollen of one variety pollinates the flower of another variety, mixing genes from both varieties in the seeds) and these plants will "always" produce seeds that are true to their variety. Pollinators do collect pollen in their flowers, though, so it’s possible that seeds may not be true, although it’s really rare.

-Cross-pollinated (c-p): Flowers only contain either the anthers or ovary, so pollen needs to be carried from anthers-carrying flowers to ovaries, in order for them to develop into fruits. Ovaries of one crop or variety that are pollinated by pollen from another crop/variety will yield a normal fruit, although the crop resulting from the seeds of this fruit (or the fruits of said crop) will not be true to either crop/variety (i.e. you’ll get a hybrid, and it’s probably not gonna be good).

Beets and swiss chards, for example, can cross-pollinate, but the result will be neither a root like beets, nor a leafy green like chards. Broccoli and cauliflower can also cross-pollinate, and will give a mixed crop that will be neither broccoli nor cauliflower (nor a happy mix of both). Gardeners have to erect barriers of any kind to prevent cross-pollination between compatible crops or plant them far away from each other (at least 50-100 feet between different varieties).

Tips & Resources

See this website for useful info on recommended distances and dominant and recessive genes.

Seeds are stored in an air-tight container (except for peas and beans, which like air) labeled with name of crop, variety, year, and any other relevant information (e.g. resistance). Proper seed storage conditions are dry and cool. Most seeds can be frozen without harm if properly dried.

Onion, leek, corn and parsnip seeds have a much shorter shelf-life than other vegetable seeds. Seeds can usually be kept 4-5 years in proper conditions.

Do not harvest seeds from diseased plants, fruits, seedpods, seedheads, etc. Do not harvest seeds from unripe fruit or immature seedpods or seedheads either: the seeds are not likely to be ready and may have difficulty germinating (if they germinate at all).

Turn and spread seeds several times while they dry. The bigger the seed, the longer for it to dry completely. The drying process can be hastened by gently heating and/or aerating the seeds, as long as the temperature does not exceed 38°C.

--> Brassicas

-----Broccoli (c-p, A)

conner-learneveryday.blogspot.ca

Will cross with cabbage, brussel sprouts, cauliflower, collards, kale and kohlrabi.

Like most brassicas, the broccoli will send out a stalk bearing small yellow flowers. These will turn into small pods. Pick the pods when they are dry and brittle.

Thresh by hand (or otherwise if you want), and separate the chaff using appropriate screens, or a fan or hair dryer.

-----Brassicas (c-p, B)

minnesotawildflowers.info

Include cabbage, brussel sprouts, cauliflower, collards, kale and kohlrabi.

Must be overwintered outdoors or indoors like beets, carrots, etc. (i.e. outdoors = thick mulch, indoors = near-freezing temperatures + high humidity)

Plant back in spring 2-3 feet apart.

For cabbages, cross-cut about 1 inch deep into the center of each head to favor seed stalk emergence. Stake, as they grow up to 6 feet tall the second year.

Cauliflower does not overwinter well indoors or outdoors.

All brassicas produce pods (like broccoli) that will dry. Harvest the pods before they are completely dry, as they tend to eject seeds when fully dried. Process like broccoli seeds.

-->Greens

-----Lettuce (s-p, A)

sanctuarygardener.wordpress.com

Lettuce seeds are usually harvested in September or October. Some cultivars will not produce seeds before the plants are frozen or dead (i.e. they don’t produce seeds).

When flowering, lettuce sends up a stalk up to a meter tall, atop which will be flowers. These flowers will produce small airborne seeds similar to those of dandelion (with a parachute-like structure of hairs). Seeds can be harvested when the parachute is formed.

To harvest seeds, one can either pick bunches of seeds at a time from the stalk, or wait until about a third of the flowers have turned into viable seed and cut the stalk. The stalk can then be turned upside down over a container and shaken, or the seedheads can be rubbed between thumb and forefinger over a container.

The seeds must then be left to dry for a few days on trays in a warm and airy place. The seeds are viable for 4 years in proper storage conditions.

-----Spinach (c-p, A)

sweetdomesticity.com

Spinach sends out a stalk bearing flowers. Seeds can be stripped directly from the stalk. Use the usual methods to remove any chaff.

-----Swiss chard (c-p, B)

beyondthekitchengarden.wordpress.com

Will cross with beets.

Hardy enough to be left outdoors throughout winter. Cut the stalk an inch over the soil surface and cover with thick mulch in fall, before heavy frost.

The next spring, trim to about 2 feet apart. The plants will grow stalks similar to beets, on which seeds similar to beets can be stripped from the stalk quite similarly like beets.

-->Roots

-----Beets (c-p, B)

wildgourdfarm.wordpress.com

Will cross with swiss chard.

Beets can be left to overwinter by covering with a thick layer of mulch (not sure if recommended for our climate). They can also be brought indoors. In that case, pull them before heavy frost in fall and cut the tops 1 inch above the crown. Handle carefully as damaged beets will rot. Store at 4-10°C in dampened sand or fresh sawdust until spring.

In spring, replant beets when it’s safe to plant them. Thin or plant beets at 2 feet apart, crowns even with the soil surface.

In summer, the plants will completely dry. Seeds can be stripped from the stalks.

-----Carrots (c-p, B)

wikimedia.org

Will cross with Queen Anne’s Lace (wild carrot).

In fall, before heavy frost, bring inside like you would with beets. Cut the tops 1 inch above the crown. Store at 4-10°C in dampened sand or fresh sawdust until spring. Some people only save and replant the crown, cutting out the rest of the root.

In spring, plant one foot apart. During the summer, carrots will grow stalks up to 6 feet tall. They produce umbels (flower heads). Seeds are ready when brown, around September. Umbels can be picked as they mature, or one can cut whole stalks and let to cure (dry) for a few weeks (usually upside down, the umbels wrapped loosely in paper bags).

Rub off seeds when completely dry. Use a screen to remove chaff.

-----Garlic & potatoes

Clonally reproduced by replanting properly saved tubers or bulbs.

Garlic must be planted in fall and covered with thick mulch.

Potatoes have their own saga on our blog.

-----Leek (c-p, B) & scallion

wikimedia.org

May cross with onions.

Overwinter easily. Cover with a thick mulch in fall, before heavy frost. Harvest any plant that does not look healthy.

The next year, the leek will send a stalk with a flower. As soon as the black seeds are visible in the flowers, cut the flower head and hang upside down, wrapped in a paper bag.

-----Onion (c-p, B)

wikimedia.org

Use harvested, dried and cured onions. Replant in early spring.

Flowering and seed harvesting are the same as for leek.

-----Parsnip (c-p, B)

veggiegardeningtips.com

Bring indoors like carrots.

Harvest seeds when dry and light brown. Seeds fall off the plant readily, so do not delay harvest.

-----Radish (c-p, A/B)

dragonplants.blogspot.ca

Treat as annual if planted in spring, will produce seeds in fall. Treat as biennial if planted in fall, same procedure as beets (harvest in fall, cut the tops, keep indoors in humid and cold conditions, replant in early spring every 20-25 cm, 5 cm deep).

Seeds are ready when seed pods are brown. If the pods are not ready at the end of the season, pull out the entire plant and hang to dry in a cool and dry location.

Open pods by hand, or smash with a mallet.

-----Shallots (c-p, B)

Generally propagated vegetatively by replanting shallots, but can be left to go to seed.

After being harvested, dried and cured, shallot bulbs can be replanted. Shallots grow better in cold conditions, so plant only in early spring or early fall. Better yields are obtained in fall, although shallots can be lost to frost.

-----Turnip (c-p, B)

livingcropmuseum.info

Same procedure as beets (mulch in fall or take indoors for winter, cut tops to 2 inches). Plant at least 2 feet apart in early spring.

Will produce pods (like other brassicas). Harvest individual pods as they turn brown; green pods do not give viable seeds.

To thresh, place dry pods in a cloth bag. Walk over them or smash with a mallet. Separate from chaff.

-->Nightshades

-----Eggplant (s-p, A)

graphicgardener.com

With a fruit that has fully ripened on the plant, one can cut the seedy part of the fruit into cubes and use the blender method (as for ground cherries and tomatillos).

-----Ground cherries & tomatillos (s-p, A)

hayefield.wordpress.com

Harvest fruits when ripe. Let ripen about a week after picking.

Use the blender method.

-----Peppers (s-p, P)

sanctuarygardener.wordpress.com

Perennial treated as annual.

Pick a ripe fruit and rub the seed mass to collect the seeds. Dry on a hard non–porous surface.

Easy peasy.

-----Tomatoes (s-p, A)

graphicgardener.com

The blender method can be used, but tomato seeds tend to get diseases. To prevent this, a fermentation process is preferable.

1) Pick really ripe tomatoes and cut in half at their equator. Extract the gel-like juice from the cavities. If done properly, the tomato can still be eaten afterward. Collect the juice and seeds in a clean container (clean is important, as we’re kinda trying to prevent diseases here).

2) Then, if processing a few tomatoes only, add a little water to the mix. If processing large amounts of tomatoes, the water from the tomatoes should be enough. Put a lid on the container and label with date and what’s in it.

3) Store the container in a warm location (15-25°C) for about three days, stirring once every day. After a couple of days, a layer of fungus will form on the liquid. This fungus eats the gel coat around the seeds and produce antibiotics that will get rid of seed-borne diseases.

4) After three days, add warm water to the container, let sit until everything settles (good seeds will be at the bottom, all the crap we don’t want will float at the top), and then start pouring gently to evacuate the floating stuff. Re-fill and re-pour until the water is quite clean.

5) Pour the water+seeds into a fine strainer. Set on a towel to remove excess water, and lay out on a hard non-porous surface to dry, in a single layer. Use your fingers to separate clumps of seeds if any. The seeds are small so they generally dry quickly.

--> Misc. fruits

-----Beans & peas (s-p, A)

Dry bean pods: awaytogarden.com

Pick the pods when dry, when a thumbnail can’t make a dent in the seeds.

Let the pods dry for another few days, more if picked in wet or humid weather. If it applies, wait until the seeds rattle in the pod when shaken.

Then, remove the seeds from their pods. This can be done by hand or, for large quantities, the pods can be threshed in a threshing box or on any kind of tarp by stepping on them (in that case, do it 

barefoot and be sure that the seeds are very dry in order not to damage them).

Dry pea pods: yearroundharvest.com

Separate the beans from the chaff using appropriate screens, wind (simply pour the seeds+chaff into another container from a certain height during a windy-yet-not-too-much day; the chaff will be carried away by the wind while the beans will fall straight into the receiving container), water (chaff and bad seeds will float; viable seeds will need to be dried again), or air compressor.

Not necessary, but it’s good to let seeds dry again after threshing, in a warm and airy location for a few more days. Inspect seeds to remove damaged or otherwise suspect ones. The seeds will be completely dry when they collapse into powder upon smashing with a hammer.

Properly dried beans and peas can be frozen without harm to get rid of any insects that could be hiding in the lot.

It can be interesting to separate seeds from particular plants or pods and label them, as they can be used for artificial selection. For example, rattlesnake beans have green-and-purple pods, but they sometimes produce pods that are greener or more purple than the average. Purple or green rattlesnake beans could probably be obtained after a few generations.

-----Cucumber (c-p, A)

aggie-horticulture.tamu.edu

Cross with one another but not with other cucurbitaceae (squash, gourds).

Let the fruit ripen past edible shape. The fruit will become golden, yellow or white. The vines can die from frost at that point without harming the seeds.

Cut the cucumber in half lengthwise and scoop out the pulp and seeds in a non-metallic container. Leave in a warm location to ferment for 3-4 days, stirring a few times every day, until the pulp turns liquid. Good seeds will sink to the bottom, bad seeds will float.

Dry in a warm and airy location, stirring once in a while to encourage uniform drying. Seeds will be dry when they are not slippery to the touch and can be broken neatly (not bent).

-----Squash & pumpkins (c-p, A)

anuts.com

Four different species: Cucurbita pepo (summer squashes, acorn squashes, orange pumpkin types, Delicata, Lady Godiva, and Spaghetti), Cucurbita maxima (buttercup, hubbard, Delicious, Banana, and Hokkaido), Cucurbita moschata (Butternut and Cheese), and Cucurbita mixta (Cushaw squashes).

Won’t cross with cucumbers and melons, nor between species. Will cross within species (e.g. acorn and spaghetti can cross, and the squash grown from their seed will be neither one nor the other).

If growing many species at once, ovary flowers should be wrapped in paper bags and fertilized by hands to prevent cross-pollination.

Summer squash must be left on the vine 8 weeks past its normal harvesting date, until its skin is as hard as a winter squash.

Winter squash and pumpkin will give more vigorous seeds if left on the vine as long as possible, about a month or two past their normal harvesting date. They can tolerate some frost.

Cut the squash in half lengthwise, scoop out the seeds and separate them from the stringy-pulpy-whatever material in which they’re entangled (do it in a bowl filled with water if necessary). Wash the seeds and lay them out on a tray in a warm and airy location, stirring them at least once a day to encourage drying. Keep plump seeds only; flat seeds are not viable.

-->Herbs

-----Chives (P)

frutasdelmundo.inriodulce.com

Harvest seed heads when seeds are black. Let dry for a few more weeks.

Rub off the seeds with hands.

-----Dill & parsley (B)

cabinorganic.com

Grown as annuals.

In the carrot family. Produce umbels like carrots. Harvest and process like carrot seeds.

-----Other herbs

Basil flowers: malaysiaria.com.my

Most herbs produce long stalks, “towers” of small flowers. Harvest seeds when the flowers have turned brown and you can see the black seeds inside the flowers (if big enough). Thresh the seed heads by rubbing them between hands.

-->Flowers

Different for each flower. Here are a few common garden flowers.

-----Calendula (c-p, A)

wikimedia.org

Let flowers dry and fold onto themselves, until brown and hard. 

Harvest by removing the hard parts from the flower.

To improve production, harvest flowers as soon as they open; calendula greatly (!) increases flower production when harvested regularly.

-----Sunflower (c-p, A)

shutterstock.com

Save seeds like you’d harvest them (but don’t bake them).

-->Misc.

-----Rhubarb (P)

sweetdomesticity.com

Usually propagated from root cuttings. If done so, it is recommended to divide the crown in early spring or late fall, when the plant is dormant. Dig out the crown without damaging roots, and use a sharp knife to cut a part of the crown (the big red roots near the soil surface). Replace soil over crown and plant cutting as soon as possible.

-----Strawberry blite (A)

ereimer.net

Harvest the berries when of a dark pink color. Dry them directly, or separate seeds by crushing the berries and mixing with water. Tiny seeds, so a very fine strainer must be used.

Self-seeding, so if you want it at the same spot the following year, you can just let some of the berries fall to the ground.