Propagation/Greenhouse Management
Part 1 – 150 | Unit 1.3
Supplement 3: Alternatives to Traditional Greenhouse Propagation
and can be built by someone without extensive
construction experience. Building a greenhouse inde-
pendently not only reduces one of the few variable
capital costs in starting a farm, but also allows the
farmer to customize the design for her/his specific
location, climate, and production goals.
Shared Propagation Infrastructure
For new farmers, and urban farmers in particular,
finding the resources and in some instances the space
for greenhouse propagation can be a challenge.
Some farms contract with commercial nurseries
or larger farms with available greenhouse space to
grow their seedlings. While this may provide some
benefits, including saving time, labor, and the need
for propagation infrastructure, another approach
is to share the costs of building and maintaining a
greenhouse with other local farms or gardens. If no
other farms in the area share this need, then finding
a nearby greenhouse from which the farmer can bor-
row or rent space is an alternative.
While sharing greenhouse space may be logisti-
cally challenging, perhaps more so in rural areas
than in urban areas, there are several benefits to this
arrangement. Most importantly, each farmer can
control her/his propagation process, materials, and
irrigation. In urban settings, farmers and gardeners
can use the greenhouse as a communal space to share
information and techniques, as well as an education-
al resource on self-sufficiency for urban populations.
Sustainable Propagation Potting Mixes
Growing media used in propagation often rely on
soilless mixes to minimize disease risks from soil
borne pathogens. Unfortunately, the most common
ingredients in these mixes often originate hundreds
or thousands of miles off-farm and require envi-
ronmentally destructive processes to produce (see
Lecture 4). Standard mixes in organic agriculture
(including those used at the CASFS Farm & Gar-
den) include compost, sand, perlite, vermiculite, and
coconut coir. Other than compost, all other materi-
als are purchased as needed. Perlite and vermiculite
are strip-mined materials and coconut coir is a by-
product of coconut production, originating mainly
in India and Sri Lanka. Aside from the added cost
of purchasing off-farm inputs, these materials carry
an embedded energy and environmental cost that
detracts from the sustainability of an agroecologi-
cal farm. While not yet certified for use in organic
systems, Growstones offer one alternative to the
widely used, but unsustainably sourced perlite
in potting media. Lecture 4 describes additional
materials that may be more sustainable sourced and
serve the save function.