Plant Material - Project Planning and Management for Ecological Restoration - page 118

needed. Removal of exotics and weeds is critically important because competition for light and
water will be a disadvantage to the native species being seeded.
Broadcasting seed has its own set of challenges. Seed comes in a wide range of shapes and sizes
and with various vegetative structures to facilitate dispersal or soil penetration. The application on-
site, if done by hand, may permit the seed to separate in a mix according to size and weight. Belly
grinder (organ grinder) devices and seed drills frequently will clog or distribute seed unevenly.
This condition can be controlled simply by using your hand to mix up the seed in the tank while
grinding. Another procedure when using large equipment is to add an inert carrier to the seed mix.
The carrier should have similar density as the seed to ensure a consistent mix; for this purpose,
bran, polenta, rice hulls, sawdust, and even sand have proven successful. The carrier should be
kept dry at all times to prevent clogging your hand-operated seed broadcasting equipment.
It may be easier to visualize seed quantities by determining how many seeds you want in a
square foot. Consider all of the species you want in your mix and whether you want every species
in the same density or not. It is much easier to visualize fifteen seeds in a square foot. Then calcu-
late up to an acre. By back calculating, you can then determine the amount of bulk pounds you
need to have a PLS of fifteen seeds in a square foot.
Some restoration designs will include species that function as “nurse plants,” nonnative plants
that do not persist on-site but that help to nurture slower-growing natives. To be an effective nurse
plant, the plant cannot directly compete with native plants in a way that interferes with the estab-
lishment of the native species on the site. Competition for resources and persistence on-site long
after the initial establishment period are concerns when using nurse plants. Many native plants
can serve as effective nurse plants. As you study various reference sites and observe the interac-
tions, you will develop an understanding of how to adjust quantities and select the species to get
your desired results.
In projects with several very limited species, or for which the seed is extremely hard to ob-
tain, application of the seed may be altered. To yield more predictable results, follow carefully
controlled application techniques in precise, suitable locations to plant the “very rare” or “very
expensive” seeds.
Seed Services
One locale can hold several seed suppliers, with a number of them offering additional services
beyond providing seed. Some governments also have seed services (e.g., plant materials centers)
that may be available under specific circumstances. The potential range of services includes the
following:
• Assessment of the maturity of seed for collection (including quick delivery of a sample to
the lab for assessment; arrange in advance to ensure service)
• Evaluation of the seed lot for debris amount
• Cleaning services for various species (this will increase the purity of the seed lot)
• Advance assessment techniques, such as radiographs to determine viable embryos
• Cleaning of empty or damaged seeds (further purification of the seed lot)