Plant Material - Project Planning and Management for Ecological Restoration - page 114

species being applied. This should not be a problem for multiple-year projects dominated by an-
nuals, because spot seeding can be conducted the following years. As with any seed, the material
should be kept dry and cool, stored out of direct sunlight, and protected from potential insect and
rodent infestation. Use paper bags (not plastic) for aeration and reducing mold growth.
For collection methods, several trips to the same site will be necessary to obtain the range of
genetic types with early and late seed set. Not all species or individuals produce the same quantity
of seed from year to year, even with suitable weather. Some species with specific habitat require-
ments may occur in small populations, requiring that you collect in a significantly large region to
obtain sufficient seed without exhausting the donor sites. Know your species and any of its special
traits so you can plan for possible backup measures.
One such measure may be to establish a controlled seed bed planting, a method called “seed
increase.” This method is very effective for providing material for annual and perennial herba-
ceous species that is otherwise difficult to obtain. A large number of donor plants should be used
to maximize genetic diversity. Seed increase is very effective when working with limited natural
vegetation or with locally endemic, endangered, or sensitive species. Some advantages and disad-
vantages of the seed increase method follow:
Advantages
• You can determine the amount of available seed seasonally based on growing beds.
• Controlled seed beds permit a higher purity of seed with much less weed and extraneous
vegetative matter.
• Controlled seedbeds with ample nutrients and water can improve the viability of seed
collected for most species.
• Seed collected and increased on-site ensures site suitability.
Disadvantages
• It requires space; depending on the number of species, this can be a significant area or
represent an added cost for land leases. If done by contract this cost is typically passed
along in the cost of the seed.
• It requires at least one season's growth (and possibly more) in advance of the project. If
the project is a multiyear installation, then this is not necessarily a disadvantage. Current
recommendations are to collect seed for no more than three years, to prevent reducing
genetic diversity on the project site.
• Costs are still higher than for stock seed from a provider. If you do seed increase on the
project site, the resource cost will be labor, water, and other maintenance costs.
• It requires a reliable source of continual labor to maintain the seedbeds over an extended
time without interruption.
Seed increase can be contracted to some growers. Your primary concern in inspecting the opera-
tions of the grower is to verify that the facilities are maintained properly and are clean and that the
seed will be handled correctly.