Coffee Seedlings in Forestry Tubes

Final Report for OS05-027

Project Type: On-Farm Research
Funds awarded in 2005: $14,957.00
Projected End Date: 12/31/2007
Matching Non-Federal Funds: $15,000.00
Region: Southern
State: Puerto Rico
Principal Investigator:
Steven Welker
USDA NRCS - El Atlantico RC&D
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Project Information


The objective of the project was to develop commercial quality coffee seedlings
through a cropping system based on forestry tube containers. The motivation behind the project was to replace the current coffee seedling system in use in Puerto Rico which relies on plastic bag containers. The existing system was judged to be unsustainable due to its economic and environmental costs, and agronomic deficiencies.

The tube container system was based on 3 elements – Ray Leach cell containers set on trays and raised benches, non-soil potting mix, and micro sprinkler fertigation. Results demonstrate that the tube containers solve the problems posed by bagged coffee seedlings. Tubed seedlings showed adequate development above ground, root systems superior to bagged coffee, and faster establishment. So far, survival rates have been good. Production costs for the tube seedlings are much less than the bag product and their environmental impact is minimal.


This project involves nursery production and transplanting of coffee seedlings in Puerto Rico. It seeks to reduce environmental damages of topsoil mining and reduce labor costs involved with transplanting coffee by using soil less potting mixes in a tube system that is currently in use in forestry enterprises in the US such as Weyerhaeuser Company. These same concepts will also be applied in the production of the related citrus crops that are used in the integrated agro forestry production system.

This project is a key component of the El Atlantico Resource Conservation & Development Gourmet Coffee Program. The coffee industry in Puerto Rico encompasses 14,000 limited resource minority producers. The coffee industry in Puerto Rico is currently exempt from NAFTA. This can not be continued into the future as per the trade agreement. In the future the Puerto Rico coffee industry must compete in the world market. The coffee industry in Hawaii has successfully made this transition with Kona gourmet coffee. Hawaii and Puerto Rico share the same high labor costs that make only gourmet coffee a viable option in these areas of the United States.

The Gourmet Coffee program is an integrated attempt to establish the gourmet industry in Puerto Rico. Nurseryman Arturo Rivera is the chairman of a 35 member farmer group that is seeking to establish a gourmet coffee business. He is also the sole owner of Vivero Matrullas Coffee Nursery. Participating farmers are members of the Specialty Coffee Association of Puerto Rico and directly represent an additional 500+ producers. For instance the President of Cooperative Agro Comercial wants to participate in the field plantings.

Mr. Rivera is raising solely gourmet coffee varieties of 100% Arabica coffee of three varieties specially selected for Puerto Rico for the members of the gourmet group and other farmers. Arabica - Robusta hybrids are dominantly planted today in Puerto Rico which does not have the “cupping” qualities for the gourmet markets. The farmers in the group raise gourmet coffee in an agro forestry system that includes plantains and citrus crops for shade and additional income.

In Puerto Rico all coffee plants are still started in flats and then transplanted into plastic bags filled with soil. These bags weigh about 6-7 pounds and are then transplanted to the fields that are typically 40-60% slopes. Topsoil needs to be mined for filling the bags. Soil extraction permits are increasingly difficult to obtain from the Puerto Rico Department of Natural Resources. This project will reduce the weight of the coffee plants by over 90% by substituting topsoil with potting mixes.

El Atlantico also has a project in utilizing rice hulls in starting a potting mix industry in Puerto Rico. Rice is imported from the US and milled in Puerto Rico. Currently only 35% of the hulls are utilized. Rice hulls available can currently be measured in acre feet. They cover an area estimated at 3 acres and 10-15 feet deep. At the same time the nursery and ornamental industry has been limited by relying solely on expensive, imported potting mixes that are dominantly sphagnum peat moss from Canada.

Project Objectives:

Objective is to develop and refine a transplanting method based on producing coffee seedlings in forestry tubes using soil less potting mix.

Performance Targets include:
Germination rates
Disease and insect problems
Size and uniformity of finished seedlings
Fibrous root development
Seedling production costs
Field survival rates

The second Objective is to develop a system that results in less environmental damage than the current system based on mined topsoil with the seedlings raised in plastic bags.

Performance Targes include:
Amount of topsoil saved
Irrigation water use
Pesticide use


Materials and methods:

Project Setup:
Tables – The crop was placed on a topless table framework constructed of angle irons. Tables were painted with a tar and gasoline homemade coating to protect them from water and fertilizer acids. The tables were 4’ x 10’ and were divided into 2 rows 100’ each, 10 tables to a row. A center aisle 4’ wide was left. Outside aisles were 1’ wide on the average.

Growing Medium and Seeding – Various mixes were prepared using vermiculite, moss peat, and fresh and aged rice hulls as basic components. The control mix was the forestry industry standard, coarse Number 2 vermiculite and coarse sphagnum peat mixed in equal proportions. In the other mixes the percentage of rice hulls varied from 50 to 33%, the rest of the ingredients being peat and vermiculite varying in proportions from 50 to 33%. No replanting of germinates was done; all cells were seeded directly with a shutter box device that seeded one tray at a time. A special tray cover assisted in the filling of the cells with the medium. The tables’ function was to facilitate labor, help drain the crop, and prevent pathogens by eliminating ground contact. A few tubes were planted with two seeds rather than one in order to gauge the benefits of this alternate method.

Tube Containers – Ray Leach Supercells 10 cubic inch volume, 1.5” diameter, 8.25” deep, 98 cells per tray. Weight of media filled, water saturated tray is less or equal to 20 pounds. Tray dimensions are 24” X 16”. Each cell can be separated individually from the tray to allow for culling and manipulation. 30,000 cells were planted and they occupied 75% of the available table space. Cells are suspended one half inch above the tray bottom. This feature, coupled to the absence of a table surface, provided for air pruning of the coffee’s tap or pivotal root. Four downward internal projections in the cell served to train all roots to point down.

Fertigation – Micro sprinklers model Dramm Pin Nozzles (green coded). Irrigation rate was 12 gallons per minute per each of the 3 stations. Each station was composed of 15 sprinklers. Each station operated for 5 minutes daily. Total daily water use was 180 gallons for all stations together. Fertilizer was a soluble 20-20-20 with trace elements at 150 parts per million. Sprinklers were installed 3’ above the growing medium surface in 3.5’ spacing. Fertilizer and chemical dosing was provided by a Dosatron injector with a 1.5” diameter inlet / outlet. Computer operated 1” diameter valves controlled water flow to the stations.

Changes over Time:
Irrigation - After excellent germination and initial growth a condition began affecting the seedlings which killed many trees and slowed the growth of the others. It set back the entire schedule planned for the project. The condition was characterized by the appearance of roughly circular yellowish spots which quickly turned black. The spots had internal concentric rings. Those arising at the leaf tip would coalesce to affect the entire lower leaf margin. Affected tissues would necrose and turn the color and consistency of paper ash. In severe cases the seedling stem would blacken and the tree would die. Examination of the roots of dead seedlings always showed them to be well developed and healthy. Appearance of the condition, as well as necrosis, was very quick. At first, a fungus was suspected, but the application of fungicides had little curative or preventive effect. Hand watering, in addition to the regular micro sprinkler irrigation, solved the problem entirely. It seems that the dense leaf canopy that forms in the maturing seedlings does not allow for adequate watering. The small droplets of the micro sprinklers do not penetrate it, only the heaviest driving rain. The problem is compounded by the fast drainage of the chosen growing media. It also seems that, in general, evotranspiration rates are greater in water loving, broad leaf tropical plants, as is coffee, than in the usual trees grown in tube containers in temperate climates, conifers in particular. The water retention of the control mix was better than the rice hull mixes. The capacity to retain water decreased with increased proportion of the rice hull component. The only mix that did not show signs of drying out under sprinkler irrigation was fine vermiculite / fine sphagnum peat in equal volume. Only 4 late planted trays were filled with this material and further crop growth is needed to determine its success in this regard. Unfortunately, such markedly water retentive mixes can be harmful in germination and early stages of development of seedlings because of the danger of rot and damping-off. Undoubtedly, our experience demonstrates that their performance in coffee is superior to highly aerated mixes as the crop matures. Hand watering required one hour daily. As a consequence, water usage increased from 180 to 360 gallons, equaling 1.5 ounces per seedling. This result compared favorably with drip irrigated plastic bags seedlings which required 1 to 2 ounces of water daily.

Growing Medium – One of the purposes of the experiment was to test fresh and aged rice hulls, locally available ingredients, as substitute components in the growing medium. Nitrogen deficiencies had been expected in the mixes which had fresh rice hulls as an ingredient, but it was hoped that the aged rice hull mixes would perform better. These aged hulls had been exposed outdoors to sun and rain for years. It was found that aging did not reduce substantially the need for extra nitrogen, particularly in the first growing stage of the crop. To counteract nitrogen need, the fertilizer dose was doubled from 150 to 300 parts per million. This dose was still within the normal recommendations for tree seedlings. Decomposition of the rice hulls was greatly accelerated as a result. After an initial period of some leaf yellowing and slow growth in comparison to the control mix, the rice hull seedlings achieved excellent color and growth rates similar to the control. A negative result of the augmented fertilizer doses was softer, flexible, and spindlier stems.

Seed Flotation – The growing media, based on the industry standard, which recommends coarse ingredients for better aeration, resulted in coffee seeds floating to the surface of the media after heavy tropical rains. Even after time consuming replanting by hand, floated seeds did not perform well. They developed damping-off and erwinia bacteria. Some sprouted on the surface and could not develop normal and useful root systems. Others were rendered sterile by their exposure to the sun and heat. Deeper planting helped but did not solve the problem entirely. In fact, planting too deep created its own problems with damping-off, abnormal stem development and cotyledon chlorosis.The only growing medium that did not exhibit seed flotation was the one composed of finely textured ingredients.

Agricultural Chemicals – The experiment started with the usual application of chemicals advised by the USDA and local agricultural authorities for coffee seedlings. Though the growing medium was sterile, the quality of the irrigation water was very poor, so it was felt that soil fungicides were needed to control water-borne pathogens. Systemic and contact insecticides were applied to kill scales, leaf miners, and beetles. Contact and systemic fungicides were used to prevent leaf spotting. In the last months of the experiment all applications were suspended, as there were signs that they were not necessary. There was incidence of cercosphora leaf fungus (commonly known as Iron Spot or American Leaf Disease), but only when seedlings were stressed by under watering. Leaf miners appeared only on the edges of the trays exposed to the walking aisles. These were the only insects and diseases of any consequence. In contrast to bag grown coffee, there was no need to control mollusks. In contrast to bag grown coffee, rat control proved to be important. On three occasions, black roof rats attempted to make nests within the dense mass of the mature seedlings, using their stems and leaves for construction material. In a few nights, 2% of the existing plantation was lost to the rats. The only effective control was the placement of one commercial rat poison station for each row of benches. It is essential that the bait station be placed on the bench rather than on the soil due to the arboreal nature of the roof rat. Stations placed on the floor were helpful but nowhere as effective as those laid on top of the tables.

Research results and discussion:

General - The aim of the project was to develop seedlings meeting or exceeding the criteria of success established for the current plastic bag system. Simultaneously, the new system had to overcome the limitations of the old in production and environmental costs, and agronomic deficiencies.

Overall, the tube container system was found to be superior to the bags in complying with the stated aims of the experiment. Though growth to maturity took longer than expected due to the factors mentioned previously (i.e. faulty watering regimen), tube seedling health and conformation were as good as the bagged trees. While the aerial part of the tube trees was less developed, as had been expected due to crowding, the tube product reached the same height of the bag seedlings. Leaf size was not as restricted as had been prognosticated, but caliper measurements of the trunks were smaller than hoped, though still acceptable. Most likely, this was caused by excessive nitrogen application which should have been reduced once the decomposition of the rice hulls had been achieved. Density of roots per volume unit of growing medium was superior in the tubes but perhaps would have been greater if the excessive nitrogen would not have prioritized the development of stems and leaves. On the date of the submission of this report only a limited number of trees had been planted. So far, survival rate has been 100%. The superior root system of the tube seedlings made for faster establishment of the plantation if sufficient soil moisture was present. The first flush of leaf and stem growth was faster with the tube than with the bag. In the following, the performance of the tubes will be compared to the problems they sought to resolve.

Production Costs:
Problem - Substantial tracts of land are needed to establish bag nurseries. This involves expenditures in constructing lots and access roads in mountainous locations and creation of infrastructure (irrigation, electrical, drainage, shade cloth houses) over a wide area.
Solution – Tube containers reduced planting area to one eighth of the bag nurseries. The size of vehicle entryways and the head house space were greatly reduced. Germination boxes were eliminated. Utility infrastructure was shrunk in proportion to the diminished planting area.
Problem – The bag growing medium must be prepared on-site using topsoil and organic materials, both which are expensive and hard to procure. Manufacture of the growing medium requires heavy equipment and special machines which must be housed in large structures.
Solution – Soil was substituted by a light weight, organic, non soil medium. As opposed to manures and composts, these materials require no government permits to process or transport. The small volume of medium needed by the tube containers required less investment than the soil mix. Reduced medium weight and volume allowed for fast manual preparation in a small area.

Problem - Transportation costs within the nursery, and to and within the farms are high because the bags are fairly large and heavy. The average weight of each filled bag is 6 pounds; its volume is 113 cubic inches. A planting worker can only carry 9 bags, weighing 54 pounds total.
Solution – Tubes decreased container weight in a 40:1 ratio or better depending on the growing medium used, each filled cell weighing no more than 2.5 ounces. Cell volume is 10 cubic inches each; volume decreased by an 11:1 ratio. 2500 tube seedlings, enough to plant 2 acres, weigh no more than 400 pounds, and can be carried in a 4’x 4’x 3’ cardboard box. An identical number of bag seedlings, arranged on 2 levels, require an 18’ flatbed truck for transport due to combined weight (15,000 pounds) and volume. A planting worker can now carry 100 or more tube seedlings weighing less than 20 pounds total.

Problem - Heavy use is made of expensive agricultural chemicals because of the large area involved and because the soil in the bags must be treated as well and its volume is high. As the growing medium is not sterile and the bags are placed directly on the ground the rate of application and variety of agricultural chemicals is increased.
Solution – The use of all agricultural chemicals, except for soluble fertilizer, was eliminated. This was made possible by lifting the crop off the ground where many pests and pathogens are concentrated; reducing the volume of growing medium thereby diminishing the volume of chemicals needed to treat pests and disease found in the medium; augmenting planting density in order to reduce the area where chemicals would have to be applied; and utilization of a sterile growing medium so as to eliminate herbicides, soil fungicides and sterilants. These factors, rather than the chemical reduction that had been hoped, allowed for complete elimination of chemicals, and consequentially, significant expenditure on these inputs.

Problem - The bag system is labor intensive in all phases of production. This is by far the greatest cost of production in coffee nurseries.
Solution – Maintenance was reduced to less than 2 hours a day, 1 hour of which was spent on hand watering. Non maintenance operations dropped from 2 months to a few days. Distribution of the seedlings to clients took minutes rather than hours.

Problem - There is a considerable expenditure in fuel and utilities. Most bag nurseries use long-throw impact sprinklers which by nature are imprecise and wasteful of water. Fuel and electricity are relied upon for machine operation involving the preparation of the growing medium, transport, etc.
Solution – Water costs were reduced by increasing planting density and by the use of efficient, fixed-head micro sprinklers having a more even water distribution than impact sprinklers. Machine and equipment use in the manipulation of the medium was cut down; one worker rapidly mixed the medium using nothing more than a shovel, the characteristics of the medium and containers permitted fast filling of tubes and economical transport.

Environmental Costs:
Problem - The heavy use of agricultural chemicals has been mentioned. The large areas taken up by the bag nurseries make containment of pollution difficult. Controlling runoff is not easy with the many streams present and typical rain levels reaching 80 to 120 inches in the mountains where the nurseries are established. Puerto Rico has one of the highest population densities in the world and virtually all nurseries are located next to homes and communities, augmenting the potential for chemical harm.
Solution – Under the conditions of the experiment, no chemical application was necessary. There was no special weather or other atypical situation which could account for this unexpected result, so it is felt that the result is reproducible for the next seedling harvest. Though the nursery location is nearly ideal for temperature and other weather related factors, it is surmised that the high density of the crop and its associated humid micro atmosphere played the determining role in controlling the coffee’s main pest, the coffee leaf miner. The sterile growing medium prevented soil insects. Soil fungi were avoided through the use of the sterile, aerated medium but the effect was counteracted somewhat by the untreated irrigation water. Mollusks did not invade the crop because it was raised off the ground and the tar coating of the tables repelled them. Nutrition, self shading, and plentiful watering kept down leaf fungi to a minimum.

Problem – In the conventional system there is extraction of precious topsoil in mountain areas in a small island possessing a delicate ecosystem, increasing the potential for erosion and land slides. The bulldozing and excavation of lots on slopes averaging 40 to 60% is detrimental to environmental and aesthetic values.
Solution – The tube nursery was established on a long narrow lot excavated on the mountain contour. This minimized the creation of tall, unstable back slopes and mitigated negative aesthetic impact. Extraction of topsoil was, of course, not necessary for the formulation of the growing medium.

Problem – Conventional nurseries are wasteful of water. Ironically for such a well watered land, usable water is scarce and expensive in Puerto Rico, due to pollution, inefficient infrastructure and management. All water resources in Puerto Rico are owned by the central government and franchised to the nurseries. With the mounting pressures from a growing population, inefficient use of water in agriculture is no longer acceptable.
Solution – Because of the concentrated planting area and small container volume, the overall water use for the tubes is similar to the most water thrifty system, that is, drip irrigation. This is so despite the windy conditions of the locality which often interfered with the settling of the droplets.

Problem - All operations within the bag nursery and seedling transportation rely heavily on the use of fossil fuels.
Solution – Cutting back on high energy operations and equipment curtailed the wasteful use of fossil fuels. Reuse and recycling of containers and trays keep the hydrocarbons spent in producing plastic in the production chain rather than in a dump or in an incinerator. By eliminating agro chemicals, whose production and make-up is based on the burning and refining of petroleum and coal, the harmful effects of these practices on the environment are also avoided.

Agronomic Deficiencies:
Problem - The combination of germination in sand beds, replanting of germinates into plastic bags, and the bags themselves promote the development of root abnormalities. These include L, J, and spiral roots and multiple tap roots.
Solution – The root systems of hundreds of tube seedlings were observed. Spiral and J roots occurred in none. Almost all cases of L and multiple tap roots were related to seed that had floated to the surface of the medium and took root or was then replanted. Multiple tap roots frequently spread out in a shallow “crow or cock’s foot” pattern which is said to cause weak anchoring of the trees in the field. In the tubes, all multiple roots were trained downward. Only field observation will reveal if this positive behavior will continue after transplant. Some of these abnormal root conditions have been vaguely ascribed to genetic factors by coffee specialists. The experiment’s results support the contention that the deformations are largely caused by mechanical and heat damage of various sorts. Because of the high germination rate of fresh and properly stored coffee seed, direct seeding was a success, both from the speed at which it was carried out and from its agronomic benefits. A source of multiple tap roots that could not be controlled in the experiment was mechanical damage to the seed embryo in the removal of the coffee rind or pulp by the seed processor.

Problem - The growing conditions and unsterile growing medium promote pests and disease.
Solution – As was discussed, placing the crop on tables and eliminating the soil component prevented contact with pathogens and water logging of the bags during occasional flooding.

Problem - The soil based medium, particularly its clay component, does not provide sufficient porosity and related root aeration, leading to losses to damping-off disease in the early stages of seedling development. Soil porosity is 50%. A soil, peat, and sand mixture in equal parts has 55% porosity. Thus, the inclusion of soil as a major ingredient (20 to 30%) in a container mix reduces porosity to unacceptable levels, when proper levels should be in the order of 80 to 90%. Most manures and composts have fine particles which act in the same negative manner as soil within containers.
Solution – In the conditions of the experiment, the control peat mixture as well as the rice hull mixtures dried out too quickly. Good results were obtained with a fine peat and vermiculite mix similar to those used to germinate in very small containers. Fine mixes can increase the danger of damping-off. Obviously, a finely tuned balance between the antagonistic properties of aeration and water retention will have to be worked out for tube grown coffee, though the results obtained so far have been encouraging.

Problem - Some losses occur in the conventional system because of over dosing of fertilizers and burning from uncomposted organic materials incorporated into the soil mix. Slow release artificial fertilizers are difficult to incorporate evenly into the growing medium and decompose too quickly under humid tropical conditions, leading to waste.
Solution – The combination of fertigation and an infertile growing medium proved to be problem free and ideal in controlling fertilization at all stages of growth.

Participation Summary

Educational & Outreach Activities

Participation Summary:

Education/outreach description:

Presentation was made by Arturo Rivera, nurseryman, and Steven Welker, coordinator to the council of El Atlantico RC&D via Power Point. We had arranged for a reporter from AgroTema newspaper to be present. Agrotema is the most widely read agricultural publication on the island. An article was subsequently published.

The project was featured in the annual report of El Atlantico Resource Conservation & Development. The report was mailed to all NRCS offices, all municipal mayor’s offices, and most of the agricultural cooperatives in PR.

Presentation was also made to senior management of USDA Natural Resources Conservation Service. They are interested in basing an EQIP Program (Environmental Quality Improvement Program) practice on this research project. There are 27 coffee nurseries on the island. The EQIP practice would aim to convert these to the new system because of the soil conservation aspect and other environmental benefits particularly in reduced pesticide use and reduce irrigation water use and discharge. NRCS would like to see a follow up project done on an economic analysis of the system before implementing on a wide scale.

The project has been discussed extensively at meetings of the Specialty Coffee Association of Puerto Rico. This has resulted in a large number of farmers visiting the nursery during the production cycle.

Free samples of the coffee seedlings are being given to interested farmers to transplant and evaluate for themselves.

An open house in planned this month for coffee experts form the University of Puerto Rico. These are key persons who assisted with the project and will help to disseminate the information.

Project Outcomes

Project outcomes:

The following are improvements that could be made on the system and future lines for research:

Increase table width from 4’ to 6’ – The 4’ width was chosen because it was a comfortable distance for working with the trees. Through our experience with the system, we have determined that the width can be increased to 6’ without loss of handling ability. This would save irrigation water and fertilizer because the effective irrigation diameter for each sprinkler is 7’, thus approximately 60% of the water and fertilizer is being lost. Increasing table width would also utilize nursery space to better advantage and cut down table construction costs. Additionally, all walking aisle space should be standardized to a 4’ width.

Fertilizer dose should be brought down to 150 ppm daily or thereabouts, in order to save fertilizer and increase the trunk caliper and hardness of the seedlings.

If any chemical applications are made they should be of low toxicity, done infrequently, and directed to the exposed edges of the crop. Nothing else is necessary. The absence of strong insect and fungal pressures opens the possibility to develop the seedlings through the organic method.

Planting depth should be no more than one inch and not less than the standard one half inch. The potting mix should be optimized so that seed flotation is eliminated. By doing so, seed depth can be held between one half and three quarter inches, which for this application is considered ideal.

The potting mix should be changed to finer materials similar to a germination type mix. If using rice hulls, the nurseryman must accept slower initial growth if the material is not composted previously. The proportion of rice hulls must be kept to low levels, especially if hulls are not composted, because they drain quickly. A cost analysis would probably reveal that, in the present and for most farmers, the trouble of buying and processing the hulls is not worth the effort. Likewise, the mixing on the farm of the new type of medium that is recommended is hardly advisable because of the extra labor costs incurred. An analysis of the physical properties of the available commercial mixes is proposed and some should be chosen that best strike the balance between water retention and aeration demanded by tube grown coffee. The aim should be to achieve high percentages of successful germination while assuring enough water retention to liquidate or reduce daily hand watering.

Double seeding of coffee in RL Supercell containers places undue water stress on the seedlings. It should not be practiced.

A production schedule should be implemented that would prevent seedling distribution to the farmers during the dry months of winter. Production protocols should be optimized to reach germination 6 to 8 weeks after sowing and to distribute seedlings to farmers 4 to 5 months after germination. In this way, two crops of seedlings could be produced in a year, the same as in drip irrigation systems.

Our experiment was done using seed from the dwarf cultivar Caturra. Test plantings should be done using seeds from tall cultivars, such as Bourbon and Typica, so as to calibrate any changes that are necessary for the cultivation of these fast growing varieties.

Addition of soil to the tube potting mix, as is practiced in Latin America, is not recommended. It impedes aeration and increases several fold the weight of the container. The purported benefits accrued from its use, such as provision of trace elements and beneficial microbial inoculation are best achieved through other means. Addition of trace elements through the fertilizer nutrient mix is cheap, while inoculants can find their way spontaneously to the crop from the forests and coffee farms surrounding the nurseries. Soil containing beneficial inoculants is usually also loaded with pathogens that are not so nice.

Irrigation water treatment is advised to reduce damping-off, as most causative agents are of the water mold family or need humid environments for their survival. A promising design incorporating a roughing filter, a slow sand filter, and an ultra violet sterilizer has been worked out. This economical set up would provide chemical-free water exceeding government potable water standards.

Though our present tube container system is simple and cheap enough to be within the reach of any farmer, the savings achieved through its adoption and the pressure from future environmental regulations might make it possible and mandatory to switch to modern nursery set ups. New mid sized container nurseries in Puerto Rico should consider from the very beginning investing in greenhouses, mobile boom irrigation, automation, recirculation and retreatment of irrigation water, climate coolers and fans, space-saving movable tables and so on. This will be the only way to be truly competitive in today’s world.

Economic Analysis

An economic analysis was not done as part of this project. This project concentrated on refining materials and methods. The future work of this project needs to now address economic analysis.

Costs were only tracked in relationship to the conventional production in bags of native soil which is substantial more expensive.

Farmer Adoption

Mr. Rivera definitely plans to continue using tube containers and will abandon the use of plastic bags. He would recommend this system to all coffee nursery owners and look forward to perfecting the system in the manner outlined above. The basic course of the protocols that were elaborated will be maintained for they proved their fruitfulness in practice. The new methods will be resisted for a while by some farmers and officials but the same can be said for the plastic bags and every other innovation in coffee when first tried out in Puerto Rico. This seems to be part of human nature but in the end the convenience of the tube containers will win the day.


Areas needing additional study

Now that the materials and methods have been refined we are ready to continue with an economic analysis.

Properly composed rice hulls still need to be evaluated. We only had fresh hulls and aged hulls available.

Seedlings need to continue to be monitored in the field into future years for growth rates and survival.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.