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 borrow or rent space is an alternative. While sharing greenhouse space may be logistically 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 educational resource on self-sufficiency for urban populations.Growing media used in propagation often rely on soilless mixes to minimize disease risks from soil borne pathogens. Unfortunately, cannabis grow supplies the most common ingredients in these mixes often originate hundreds or thousands of miles off-farm and require environmentally destructive processes to produce .
Standard mixes in organic agriculture include compost, sand, perlite, vermiculite, and coconut coir. Other than compost, all other materials are purchased as needed. Perlite and vermiculite are strip-mined materials and coconut coir is a byproduct 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 agroecological farm. While not yet certified for use in organic systems, Grow stones 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.Genetic diversity among seeds is vital not only to the resilience of plants, but also to the resilience of communities that depend on plants for their livelihoods. Both crop diversity and farmers’ freedom to grow crops of their choice have been severely diminished in the last eight decades, as production agriculture’s focus on high yield intensified and as patent law gave agrichemical companies private patent rights to seeds. Today, global crop diversity is shrinking as the worldwide adoption of patented, genetically engineered seeds accelerates. GE varieties are quickly becoming dominant in commodity crop agriculture in many countries. As of 2009, 90 percent of corn, 84 percent of soybean and cotton, and 64 percent of canola grown in the United States is from GE seed.
As a consequence of changes to U.S. patent law in 1980, seeds were, for the first time, subject to patents and ownership by individuals or corporations. Nearly all GE and hybrid seeds are now patented and owned by the companies that sell the seeds commercially. As of 2009, five companies accounted for 58% of global commercial seed sales.2 Dramatic increases in seed prices have accompanied seed industry consolidation, due in part to technology fees on GE seeds that companies can charge with their increased market share. Farmers who buy GE seeds are also required to sign technology use agreements , essentially legally enforceable contracts, limiting how the seed is used, to whom it is sold or transferred, and what it can be used for. Most TUGs prohibit research trials using GE seed or comparing yield performance between GE and other seed. Nearly all TUGs prohibit seed saving, requiring farmers to purchase new seed each year. To enforce the restriction on seed saving, one company in particular, Monsanto, employs 75 or more investigators with a budget of $10 million to aggressively patrol and sample crops from farmers’ fields to test for unauthorized use of their GE seeds.3 Any unauthorized use of its seed—intentional or not—is considered patent infringement, thus giving Monsanto a financial incentive to police farm communities. Indeed, the company has sued nearly 150 farmers in several U.S. states for infringement, resulting in 72 recorded judgments totaling $24 million and an estimated $80–160 million more in out-of court settlements against farmers4 .
The other seed companies mentioned above engage similar tactics against farmers who save their patented seeds. India has also seen drastic impacts on farmers as a result of GE seed use. GE cotton was introduced to Indian farmers in 2002 as part of new development policies aimed at stimulating economic growth. By 2009, nationwide adoption of GE cotton reached 85 percent, with rates as high as 95 percent in some states. While crop yields initially rose, the new varieties, owned and licensed by Monsanto, increased monetary and resource costs for cash-strapped Indian farmers with limited access to water.GE cotton seeds cost farmers two to ten times more than non-GE varieties5 and, because of TUG requirements, had to be purchased each season, forcing many farmers to borrow money just to buy seed. Then, in order to secure the high yields these new, expensive seeds promised, farmers who traditionally relied on rainfall for irrigation borrowed more money for wells and irrigation equipment to provide the thirsty GE crops with a steady supply of irrigation water. GE seeds are genetically identical clones bred in closely monitored field trials under optimum conditions. As a result, they require optimum conditions to produce the increased yield they are advertised as capable of producing and that is necessary for farmers to be able to pay back the mounting debt from seed, pesticide, and irrigation purchases. In a year of poor rainfall or when a well pump fails, many farmers suddenly find themselves paralyzed by debt. In the years following India’s adoption of GE cotton, farmers fell deeper and deeper into debt to recoup their investment in GE seeds, and scores of smallholder farmers eventually gave up trying. From 2002 and 2010, 153,727 farmers committed suicide in India.6 Many more farmers, in India and elsewhere, find themselves in a similar situation, heavily burdened by debt and pressured to cultivate more land just to make ends meet. In an effort to provide farmers with more options, organizations such as the Organic Seed Alliance and The Land Institute are researching and breeding organic seeds for commercial production and for sustainable farming systems based on perennial crops. Unlike hybrid and GE seed, these are generally open-pollinated varieties that farmers can save from season to season. Still a minor source of seeds even for organic growers, cannabis growing equipment more government-funded research is needed to develop commercially viable organic seeds for the wide variety of crops grown in the U.S. and abroad. Although the debate about genetically engineered crops is likely to continue for the foreseeable future, it is important to recognize the serious impacts of this technology on the viability of farm communities around the world today.
From public research to farmer sovereignty and suicides, the effect of corporate control and ownership of seed on a farmer’s ability, and right, to save and replant seeds has far-reaching implications for the well being of individuals and of agricultural communities.Evaporation is the transformation of water from a liquid into a gas. Water volatilizes into the air easily, especially when it is hot and windy. Evaporation happens only at the surface of a liquid, so the greater the surface area-to-volume ratio of the water, the greater the evaporation rate. This means that you lose more water to evaporation from water sprayed in drops into the air than you do from water in a drip tape line or in an irrigation canal or ditch. The evaporation rate for a given day can be measured. One way is by placing a known quantity of water in a container of a known surface area and timing how long it takes to disappear. The plant uses water to transport nutrients and air, to maintain its structure, and to thermoregulate . The transpiration rate of a plant is the amount of water a plant uses up over a given amount of time. This value is harder to measure, as it is difficult to assess the minimum amount of water that a plant needs to be healthy. The plant could be using less water than you are giving it. You could measure this in a very controlled environment by giving similar plants different amounts of water and seeing the effects. Fortunately, this can also be looked up. Transpiration rates found in reference tables are generally for mature plants; any plants that are working more will transpire more. It is equivalent to breathing for us – adults use more air than children do, you use more when you are exerting yourself, etc. The evapotranspiration rate is the amount of water that needs to be replaced over a given amount of time to make up for the water that has been used or volatilized. The evapotranspiration rate is measured for mature plants in a given region on a given day. Precipitation and irrigation are the two primary sources of water that plants use. Plant leaves and soil surfaces temporarily retain some part of the water applied to the field, but this part readily evaporates. What remains percolates into the soil. Plants extract the infiltrated water through their roots and transport it up to their leaves for photosynthesis. In addition to water, plants need carbon dioxide and light for photosynthesis. In order to take in CO2 from the atmosphere, plants open their stomata, the microscopic pores on the undersides of leaves. It is during this process that they lose water to the atmosphere.Tensiometers are placed directly into the most active part of the crop’s root zone, at depths ranging from 6 inches to as deep as 48 inches. The most common placement depths are 6 and 12 inches for shallow rooted crops . Two tensiometers are often placed next to each other so that soil moisture can be monitored at different depths at the same location. The deeper location tends to maintain a higher percentage of moisture compared to the more shallow placement, and this difference provides the irrigator with a good representation of below-ground moisture dynamics that can be a great help in determining both timing and amounts of water needed to meet the crop’s needs over time. Tensiometers should be placed at a number of locations across the field to reflect different soil and irrigation conditions. They should be left in place for the duration of the crop cycle and read as often as once a day to inform irrigation scheduling decisions. Placement location and method of installation are critical for accuracy. Tensiometers should be placed within the root zone directly in the “wetted” area that receives either drip or sprinkler irrigation. In sprinkler-irrigated systems, place the tensiometers between sprinkler risers where maximum uniformity is often observed. In drip-irrigated systems, place the tensiometers off to the side of the drip line but still within the wetting pattern of the drip. Prior to placing the tensiometer in the soil the semi-porous ceramic tip must be soaked in water overnight to insure that it is adequately moist so that water can easily move from the sealed tube into the surrounding soil. To install the tensiometer the irrigator makes a hole in the ground to the desired depth and the same diameter as the tensiometer. There are dedicated tools for this purpose, but a soil probe can be used as long as it is the same diameter as the tensiometer. A slurry of soil and water is poured into the bottom of the hole to ensure good tensiometer-soil contact , and the tensiometer is then pushed into place in the hole. The tensiometer location should be marked with a flag tofacilitate locating the instruments for monitoring. Once installed it usually takes several readings over a period of several days to start getting accurate readings. Tensiometers have a water reservoir above the sealed column of water that resupplies the plastic column, since the plant roots constantly extract very small quantities of water from the sealed tube. To refill the sealed tube the irrigator simply unscrews the cap on the reservoir and this opens the seal below the reservoir, allowing the excess water in the reservoir to flow into the lower tube.