Collecting Seeds
Seed Collectiing
When one is collecting seeds to grow their own plants or to sell, the first thing that needs to be done is to learn what the ripe seed head looks like for the plant. Collect the seeds just as the pod is opening or seeds are just starting to be released. Let the seeds dry for some days, if not weeks in paper bags in a dry location or in paper cups. Newly harvested seed often contains a high percentage of water and it needs to dry down in order to be stored safely. After it has dried for several weeks, it is then ready for the next step. The seed should be cleaned, as well as you can manage, by hand. Commercial seed cleaning equipment is very costly so I do it by hand. I take a small amount of seed, maybe a tablespoon and rub it vigorously and firmly between my palms. What I am trying to accomplish is getting seed out of seed heads and pulverizing chaff to smaller bits. Eventually, if you do this enough, callouses will form on your palms and it will not bother them as much. I then put the whole lot on a paper plate, tilt it and while gently tapping and pushing the chaff up to the top of the tilted plate, the seeds roll down to the bottom. This method often has mixed results. You can also blow on the plate while doing this to remove more chaff. It’s a fine line between blowing the chaff off the plate and blowing seeds with it. Large seeds can be sorted away from the trash one by one. Store cleaned seed in paper envelopes. I like the yellow ones used for coins. Paper envelopes allow the seed to dry down further and if they are stored in a closed container, out of direct sun, in a cool place (fridge works well), their viability will last, depending on the species, a year or more. Label each envelope with the plant name and the year they were collected. If you would like, put the germination percentage on the envelope as well.
How does one figure germination percentage?
Germination testing. This is relatively simple. Take a number of seeds, at least 10, up to 100. I put them on a piece of paper towel, fold it up and dip in water. Squeeze out the excess. Put the packet in a zip lock bag, I use the little 2x3 inch bags. Label it as to the seed name, the date the test started, and the number you started with. Put in a warm place if seed requires warmth to germinate or in the fridge if it germinates in cooler temperatures. Check in a few days to see if any have started germinating. Count all those that are showing roots as germinated and remove them from the packet. Keep track of the number. I usually keep track for what I consider a reasonable amount of time…about 2 weeks unless I know the seeds take longer to germinate. Over this time period, make sure the paper towel stays moist. Take the number of seeds that germinated and divide that number by the number you started with. You will get a decimal number, say .92. Multiply this by 100 and you have your germination percentage…92 percent. Sometimes, seed is so tiny it is easier to germination test them by sowing them in seed starting mix. Again, keep track of how many you started with and how many germinated to determine the percentage.
Many perennials need special treatments to get them to germinate. This is a survival mechanism for the species. Some seed may germinate immediately upon falling to the ground, some may need a cold, moist stratification…winter, or need to be damaged by passing through the gut of an animal or bird. When germination testing these, any pretreatment to induce germination needs to be done so you can see how many seeds germinate.
When one is collecting seeds to grow their own plants or to sell, the first thing that needs to be done is to learn what the ripe seed head looks like for the plant. Collect the seeds just as the pod is opening or seeds are just starting to be released. Let the seeds dry for some days, if not weeks in paper bags in a dry location or in paper cups. Newly harvested seed often contains a high percentage of water and it needs to dry down in order to be stored safely. After it has dried for several weeks, it is then ready for the next step. The seed should be cleaned, as well as you can manage, by hand. Commercial seed cleaning equipment is very costly so I do it by hand. I take a small amount of seed, maybe a tablespoon and rub it vigorously and firmly between my palms. What I am trying to accomplish is getting seed out of seed heads and pulverizing chaff to smaller bits. Eventually, if you do this enough, callouses will form on your palms and it will not bother them as much. I then put the whole lot on a paper plate, tilt it and while gently tapping and pushing the chaff up to the top of the tilted plate, the seeds roll down to the bottom. This method often has mixed results. You can also blow on the plate while doing this to remove more chaff. It’s a fine line between blowing the chaff off the plate and blowing seeds with it. Large seeds can be sorted away from the trash one by one. Store cleaned seed in paper envelopes. I like the yellow ones used for coins. Paper envelopes allow the seed to dry down further and if they are stored in a closed container, out of direct sun, in a cool place (fridge works well), their viability will last, depending on the species, a year or more. Label each envelope with the plant name and the year they were collected. If you would like, put the germination percentage on the envelope as well.
How does one figure germination percentage?
Germination testing. This is relatively simple. Take a number of seeds, at least 10, up to 100. I put them on a piece of paper towel, fold it up and dip in water. Squeeze out the excess. Put the packet in a zip lock bag, I use the little 2x3 inch bags. Label it as to the seed name, the date the test started, and the number you started with. Put in a warm place if seed requires warmth to germinate or in the fridge if it germinates in cooler temperatures. Check in a few days to see if any have started germinating. Count all those that are showing roots as germinated and remove them from the packet. Keep track of the number. I usually keep track for what I consider a reasonable amount of time…about 2 weeks unless I know the seeds take longer to germinate. Over this time period, make sure the paper towel stays moist. Take the number of seeds that germinated and divide that number by the number you started with. You will get a decimal number, say .92. Multiply this by 100 and you have your germination percentage…92 percent. Sometimes, seed is so tiny it is easier to germination test them by sowing them in seed starting mix. Again, keep track of how many you started with and how many germinated to determine the percentage.
Many perennials need special treatments to get them to germinate. This is a survival mechanism for the species. Some seed may germinate immediately upon falling to the ground, some may need a cold, moist stratification…winter, or need to be damaged by passing through the gut of an animal or bird. When germination testing these, any pretreatment to induce germination needs to be done so you can see how many seeds germinate.
Saturday, November 6, 2010
Author: Shanti
This is my favorite aspect of growing plants. I am perpetually fascinated by propagation and at the age of 8, my grandmother and an aunt gave me cuttings to root and I was hooked into a life of hobby/obsession/business.
Starting seeds.
Different species of plants have different requirements for germination. The ones most people are familiar with are the easy to grow ones...marigolds, beans, etc. Usually, annuals are the easiest: sow at the proper depth, provide consistent moisture and warmth and viola! You have seedlings. Annuals live one year and die. They usually profusely seed and their goal is to quickly germinate when conditions are right because they only have one shot at reproduction. They need to germinate quickly, grow quickly, and reproduce quickly (flower). These seeds contain very little if any germination inhibitor. The most important criteria for planting this kind of seed is getting the planting depth correct. Some seeds need light to germinate. Their seeds should be sown on the surface and not covered with soil. Sowing depth is information provided on the seed packet. If not, the general rule is not to cover seeds more than 3 times their diameter. For really tiny seed, just press into the soil and water gently.
Then, there are the seeds which require special treatment. Many perennials and biennials need certain conditions in order to germinate. These are adaptations to continue its species in the climate it lives in. Perennials and biennials , which come from cold climates, often need the special treatment called stratification to overcome seed dormancy. I find perennials often have, within one batch of seed, various amounts of dormancy. This is so only a few may germinate right away and the rest become part of the seed bank in the soil to provide seedlings in the future. An insurance policy of sorts against something happening to the stand of plants. This isn't a very handy strategy to deal with if you want to grow a lot of plants from the seeds. Often perennial seed needs stratification to either cause germination to happen or it unifies and improves germination. The easiest way to stratify seeds is to sow them in the fall in the place they are to grow. Let nature take care of it. Another way, is to sow the seed in a container that can be covered with plastic and put in the fridge or easier still, the seed is put in a plastic bag with damp peat or sand and a pinch of cinnamon to inhibit mold growth and this is put into the fridge for the required time. Sometimes, it's only a week, sometimes it's a few months, sometimes it is leave in there until they germinate. In some instances, you may need to freeze the seed for a certain length of time
Sometimes seeds only have a partially developed embryo so needs a period of warmth, then cold, then warm again. The length of time varies by species that have this type of dormancy.
Then there are the seeds that require soaking in warm water. Many of the legumes need this. Wild sweet peas, lupins, and locust tree seeds all should be soaked before sowing to improve germination. Plant all that swell. Check daily because they can actually swell too much and die. Ones that do not swell, either are dead or latent. You can try the next method to help improve germination of the latent ones.
Scarification is another seed treatment that is sometimes needed to get seeds to germinate. Some seeds need to have water impermeable hard seed coats abraded or nicked to allow water to get into the seed to start the germination process. This can be done with a knife, sandpaper, or a file. Only go into the seed coat until you see light, some shade of white, material. Also, most seeds have an indentation where the embryo is. Do not make this nick near the indentation because you may damage the embryo and the seed will die. I like to scarify on the ends or the opposite side of the indentation. Then the usual procedure is to soak the seed in water. Seeds which come from fruit often need this kind of treatment. There are those seeds that come from fruit which needs to pass through a bird or animal digestive tract. Strong acids in the gut damage the seed coat. Most people do not have access to strong acids to do this and physical scarification may be the only practical method.
Another method is to soak the seed in a plant hormone that will stimulate germination. Again, most people do not have access to this chemical and the following can be used as an alternative.
Natural wood smoke has been found to stimulate seeds to germinate. The wood from the seeds' environment works the best, but other smoke may be just as valuable. Smoke discs can be purchased, liquid smoke flavoring, or putting together complex methods of catching smoke from a fire on a damp cloth, are also usable. Almost all the seeds from Australia need smoke in order to germinate. There are compounds in the smoke which overcome dormancy, as if a fire just passed through their environment and the landscape needs repopulating with plants.
Some seeds need a combination of all these methods. How is someone to know what a seed needs to germinate? There is an incredible website put together by Tom Clothier (search by that name) that is a huge data base of species and their requirements. Other sources are seed packets, but I've often seen them listing sowing conditions which will not result in germination. It's best to check another source.
Remember, the success of starting seeds comes with finding out what conditions the seed needs to germinate and then provide those conditions. It's that simple.
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