Hort 4040 Seed ActivitiyRubric

The purpose of this laboratory is to familiarize you with several seed preparation techniques that you can pass along to your students.

Recommended technique: Do this: Why we do this: Done:

Seed Soaking:
Many seeds will germinate over a two to eight week period. To gain uniformity, pre-soak the seeds and plant only those that show signs of imbibition / Place seeds in very hot water 100-120 degrees F for 6 to 48 hours, Look for seed expansion as a sign of imbibition / In commercial production, having seeds germinate together allows a crop to finish uniformly. This is essential when timing flowering plants.
Seed Scarification
Many seeds have hard seed coats that need to be scratched before they can imbibe water. / Using a file or sandpaper, scratch the seed coat and then soak or plant directly into moist soil. / Seeds such as Locust, Lupines, Water Lilies, have impermeable seed coats. Freezing and thawing over several weeks or years can break the seed coat. For uniformity, we do this by hand or use a tumbler to scratch.
Seed Stratification
Many seeds neeed a cold/freezing period to mature and.or overcome chemical dormancy. This is an easy/clean way to accomplish this at home. / Makes a wet-towel seed burrito and place in a sealable sandwhich bag. Place in refrigerator for 3 weeks, then in the freezer for 12 weeks, then back into refrigerator for 3 weeks / Stratification allows immature embryos to grow, seed inhibition chemicals to break down, and seed coats to develop micro cracks for water imbibition
Photoperiod Treatment
Seeds can be periodic, using changes in the suns wavelentghs as the earth tilts towards the sun.Some seeds also need heat to germinate. / Place seeds on Paper plate. Irradiate at 4000 fc for 1-2 days using an incandescent lamp. Set light so that seed/plate temperature does not exceeed 120 degrees F. / Many seeds from wild, northern regions require infrared light to germinate. This includes native plants, Lettuce, Asclepias. Burying seed prevents light and hence prevents germination.
Tiny Seed Disbursement
Very tiny seed is impossible to distribute by hand. This technique makes the task easy and relatively uniform. / Using a small via or jar, add 1/3 volume colored sand and add seeds to sand. Mix well, sprinkle so as to use all seeds in the area you plan to use for this crops germination. / The sand acts as a medium you can see and spread easily. Colored sand is best. Try to estimate coverage to uniformly distribute the seeds.
Berry Roll
Seed from fleshy fruit can be a real problem unless you have a clear strategy. The berry roll keeps the mess under control. / Place berries on a paper towel. Push down with thumb while applying a forward/backward movement. Once pulp is seperated from the seeds, collect seeds, rinse in cold water if required, and plant. / Seperating pulp from seed is important. Pulp can sometimes be host to bacteria and fungi that are not conducive to germination. Seperation also makes it easier to handle and distribute seed.
Non-dormant Seed
Some seeds can be planted directly.
Lemons, Oranges, Pecans, Etc. Most tropical plant seeds do not need or have dormancy. / Plant seeds in moist soil within hours of collection. Do not chill. Do not let them dry out or get hot. Moisten soil immediately. Keep above 60 degrees F! / Seeds that do not require a dormancy treatment can often be triggered into dormancy by refrigeration, heat or drynness. When in doubt, look it up!