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A team of volunteers collecting seeds from a field

How To Collect and Store Seeds

One way to acquire native plants very cheaply is to collect your own seed. This can come from plants you or a neighbor already have, or from plants growing wild in your area.

We need to know how to collect. Timing the collection of seeds is a skill of observation. We need to ensure the seeds are ripened to be viable, so patience is necessary. Yet also, we cannot wait too long after the ripening or else we will miss the seeds as they get eaten by birds, insects or mammals, or are scattered by the wind or water.

Most wild seed are collected by hand. This is because desired species don’t typically grow in pure stands, and the topography of their environments often limits using mechanical equipment.

First, A Few Rules

Always get permission from the landowner when collecting on private land, and never collect on public land. Areas destined to be developed or destroyed in the near future provide excellent sites for collecting seeds, provided the landowner has given permission.

Never collect seeds from rare or endangered species — collect only from plants that you find growing abundantly in a given area to ensure that you do not eradicate an isolated population.

Take at most only one-tenth of the seeds so that enough seeds are left to reseed and perpetuate the stand.

Scouting areas during the flowering season is critical because relocating plants can be difficult once they have turned brown from frosts. Colorful flowers make it easy to delineate the extent of the population on the landscape.

Getting Organized

Collected seeds from a garden in the gardener's hand

Plants are easiest to identify when they are flowering, so it is a good idea to mark individual plants with flagging tape or to write down specific landmarks to help you relocate populations when the seeds are ready.

The tools and material you will need depends on the size of the harvest. Basic equipment includes gloves, boots, drop cloths, pruning shears, boxes, baskets and paper and/or canvas bags. Although plastic bags may be used for collecting, storing seeds in airtight containers or plastic bags will encourage mold growth. Many plants can be stripped by hand or the seed can be beaten onto drop cloths.

Guidelines For Seed Collection

Wait until the seed is ripe. Often the seed will become hard, dry and dark in colour. The parent plant may show signs of dying back. Some seeds may have already dispersed.

In some cases, you can pull or shake off the seeds. In other cases its easiest to cut off the seed head and clean it at home later.

Gather fruits from the ground only if they have recently dropped.

Keep seeds dry. Put them in a paper (not plastic) bag or envelope until they are completely cleaned and dried. Once the seeds are cleaned and dry they can be kept in plastic bags, preferably in a dry cool dark place. Remember to label them carefully with the species, the date and the location where they were collected.

Most seeds mature in the fall and are intended to germinate the following spring. It is often necessary to persuade a dormant seed that it has been through a winter. The exact requirement for each species can be looked up, but the commonest is cold damp stratification. This means moistening the seed and placing it in a cold environment for one or more months before planting.

Like most living things, newly matured seeds can be sensitive to temperature extremes. The embryos within may die if exposed to extreme heat. Take care of your seeds after collecting. It’s best to collect the seeds in paper bags, not plastic. Label the bags with collection information.

Stratification: Stratification is a process of treating seeds to break seed dormancies and initiate the germination process in spring.
Read more: Seed Stratification

Seed Cleaning and Preparation

Flower heads and husked seeds on a tray

Seeds should be collected just before or as the pod turns brown and dries and before it splits or bursts open (dehisces). The pods should be dried in single layers spread thinly on canvas cloths, screens or trays elevated from the ground. Curing on the pod may take longer for species other than legumes.

Air-drying takes one to three days, depending on the humidity. After the seeds have dried, you can extract them from the pods by beating or threshing. A mature pod will often twist and split open to drop the seeds.

Although not all seeds need to be cleaned before storage, those with pulpy fruit should be cleaned to prevent mold. Remove the pulp of large fruits by hand by rubbing on a screen or mashing with a wooden block, rolling pin, or fruit press being careful not to damage the seed. You can clean smaller fruits with a blender, as long as you are careful not to damage the seeds. Blend a small amount of the seeds in a two to one ratio with water. Use brief, intermittent agitations at low speed and then strain the mixture to separate the seeds from the pulp.

Thrashing seeds (separating seeds from the rest of the collected plant material) is optional, but it does have at least two advantages: it reduces the volume of seeds to be stored, which saves on storage space and deters insect eggs, mold spores and other seed-disease vector, most of which are removed and discarded along with the chaff. The easiest way to thrash seeds is to rub the collected material against a coarse screen with a gloved hand.

Seed Storage

Flower heads and husked seeds on a tray

The two most critical necessities for storing seeds are constant temperatures and low humidity. A temperature of 50° F or less and a humidity of 50% or lower are ideal.

Store seeds in the refrigerator, not the freezer, until you are ready to plant. Low temperature, humidity and light level protect seed longevity. If it is not practical to store seeds in your refrigerator, store them in any place that is cool, dark and dry, protecting them from insects as much as possible.

Store the seeds in paper sacks to allow good air circulation and prevent molding. Do NOT store seeds in plastic bags or other non-breathable containers unless they are air-dried thoroughly first. It is important to include basic information on labels, including date of collection, species name, location of collection and name of collector.

Dusting the seeds with a mild insecticide will help prevent insect infestation and kill any pests collected with the seeds. Or, you can insert a pest strip for several days while leaving the paper bag open to allow insects to escape. Freezing the seed for a brief period may also be a viable alternative.

Seeds of fleshy fruits should be kept moist to maintain viability. If allowed to dry out, they will either germinate prematurely or not at all. This type of seed should be planted immediately or mixed in a one-to-one ratio of moist sand or in a vermiculite or perlite mixture (depending on seed size), and stored in a cool place.

If the root emerges from the seeds during storage, the seedling should be removed and planted immediately.

A Few Tips

Wetland Seeds can be collected in late summer when flowers have turned into seed capsules. Watch insect and dragonfly activity from the shoreline and you’ll be able to tell when the small sedges, rushes and grasses are in bloom (lots of insects and dragonflies buzzing around) and when they are in seed (few to no insects and dragonflies). This is helpful since the seed heads are usually nondescript and difficult to tell from the flower heads, especially without a good, close-up, in-the-hand specimen to examine.

Wetland plants may have lots of tiny floating seeds, like cardinal flower (Lobelia cardinalis) . Or they could have larger floating seeds with air pockets such as pickerelweed (Pontederia cordata) . These eventually sink to the bottom as they get waterlogged in late fall (after migrating ducks and geese have had their fill). Floating seeds will be distributed across the surface of the water often in late summer over a long period, so urgency in collection is not needed, unlike with forest plants. A seed capsule that starts drying out from the top down to the stem, like monkeyflower (Mimulus ringens), can be cut off the plant as soon it is mostly dried. The remaining seeds will mature, i.e. dry out, if kept inside the capsule in a container.

Meadow plants tend to bloom most prolifically late in summer to late fall. Since meadows are open habitats, wind is the preferred method of seed dispersal. Many tiny airborne seeds (goldenrods or Solidago spp., and Aster spp.) are blown off seed heads during fall storms. Many grasses and other fall seed-producing plants like cattails (Typha latifolia, T. angustifolia) , common milkweed (Asclepias syriaca) , and Joe-pye weed (Eupatorium fistulosum) also disperse their seeds this way. Capture the seeds when fluff first appears and before the seeds are all wind-dispersed. Fall-migrating birds searching for food help tremendously in seed dispersal, so seeds from the Compositae (daisy or sunflower) family, including black-eyed Susan (Rudbeckia hirta) are plentifully produced with open faces and stiff stems making them ideal landing pads. The seeds are mature when the seed head dries and the seeds change from dark brown to ashen gray. Vigorous rubbing will pop the square-sided seeds out of their head.

More Gardening Tips:

 How To Use Coffee Grounds In The Garden
 How To Use Eggshells In The Garden
 Best Practices For Perennial Plant Fertilization
 How To Use Rooting Hormones
 Spring Pruning Basics

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