Tour of Cuisinart Resort & Spa Hydroponic Farm
Dr. Howard Resh

1. Lettuce Ponds:

As you enter the south entrance there are two lettuce ponds (Photo 1). In this raft culture the plants are floating on Styrofoam boards with their roots suspended into the nutrient solution below (Photo 2). Plants are seeded into 1-inch rockwool cubes. After 18 days they are transplanted to the “boards” of the raft culture system. The plants are placed into the holes of the rafts with the cubes in which they are growing. The nutrient solution is a special lettuce “recipe” composed of 13 essential plant elements.

Lettuce is seeded, transplanted and harvested every day. Two boards are harvested, cleaned and transplanted each day giving a daily production of 128 head. There are a total of 52 boards in the combined two lettuce ponds. The growing cycle of the lettuce in the ponds is 26 days.

The nutrient solution is cooled by chillers to a temperature between 65 and 70 F. This prevents root diseases and delays the bolting (seeding) of the lettuce. The solution is circulated and aerated by a pump and perimeter piping in the bottom of the pond. The pond is 12 inches deep.

 

2. Plant Towers:

These consist of 10 Styrofoam pots stacked one on top of the other by rotating each pot 45 degrees to the one immediately below. This configuration of the pots exposes their four corners. The pots are filled to within 1 inch of the top with perlite. One bok choy or up to 10 to 12 seeds of herbs are sown in each corner (Photos 3 & 4). Each plant tower is fed with two drip lines to the top pot and one in the middle to provide nutrient solution from an injection system.

 

3. Bato Bucket System:

The bato bucket system is used to grow vine crops such as tomatoes, peppers and cucumbers that may be trained vertically with support strings. The substrate for the bato buckets is perlite. Each plant receives nutrient solution from a drip irrigation line located at the base of the plant. The excess solution is collected below the buckets in a drainpipe that conducts the spent solution to the “gray-water” tank, which supplies irrigation to the outdoor landscape plants. The nutrient solution is prepared as a concentrate in “stock tanks”. There are two stock tanks and an acid tank. The concentrate is diluted back to its normal strength by an injector system. It also adjusts the pH with the use of an acid or base solution contained in a smaller tank.

a. Tomatoes:
Two tomato plants are grown in each bato bucket. The plants are trained vertically by the use of plastic clips onto the support strings. The plants are alternately sloped to each side in a V-cordon method to maximize light utilization. All suckers are removed at the leaf axils to get a single stem plant as these are staking varieties. The plants will bear fruit after 3 months and continue up to 10 months (Photo 5). By that time their stems reach 25 to 30 feet in length. They are lowered and leaned weekly by undoing extra string from special hooks (Tomahooks) that are slid along the support cable above. The plants are moved along and around the end of the row. Lower leaves are removed to permit adequate air flow under the plants.

b. Peppers:
The peppers also grow in the bato buckets of perlite similar to the tomatoes. Like tomatoes and cucumbers the seeds are started out in rockwool cubes, then transplanted to rockwool blocks before transplanting to the bato buckets. Peppers are ready to transplant to the bato buckets in 6 weeks from sowing. Each plant is fed with a drip line conducting the nutrient solution from the central injector system. Two pepper plants are placed in each pot. Similar to the tomatoes they are trained vertically. One difference is that the plants are allowed to bifurcate once giving each plant two stems. These stems are trained in a V-cordon method to allow sufficient light penetration into the resultant canopy. The plants will begin to bear fruit after 4 months. They will reach about 13 feet by 10 to 11 months, so are lowered in our greenhouse due to the low gutters designed for the structure to withstand hurricane winds up to 150 mph. There are a number of different varieties including red, yellow, orange, and a hot pepper (Photo 6).

c. European Cucumbers:
These plants are sown every 5 weeks. They will begin fruiting 5 weeks after sowing (Photo 7). Only one plant per pot is planted as they have much larger leaves than tomatoes or peppers and intercept more light so wider spacing is necessary. The cucumbers are also trained vertically up to the support wires, where they are topped and several suckers allowed to grow over the wires and come down. All suckers, tendrils and some of the fruit are removed from the main stem to allow the plant to become vigorous. This vigor is needed in order that the plant may support the heavy fruit load later.

The first fruit will be allowed to form at the 7th node and then continue as the plant grows up and over the support wire. The plants grow 6 inches per day at this stage. The crop will grow 10 to 12 weeks depending upon its health. During the 5-week period of production each plant should yield from 2 to 3 fruit per week. We stagger the sowing of the crops by 5 weeks. As one crop starts to produce we will remove the older row of plants and sow seeds for it to repeat the 10-week cycle.

 

4. A-frames:

This is a water culture system in which the solution is recycled to a cistern tank. It is called nutrient film technique (NFT) for the thin film of nutrient solution flowing underneath the roots of the plants. The A-frame design permits more plants in a unit area. The system is most suitable to low profile crops such as herbs and lettuce. Plants are started from seed in rockwool or Oasis cubes.

 

5. Raised Beds:

These beds contain about 8 inches of sand with 4 inches of peat and perlite mix on top. They are used for the production of lettuce, arugula, green bunching onions, basils (Photo 8) and bush (string) beans. All plants are irrigated by a drip system as part of the overall injector system.

 

6. Injector/Nutrient System:

The plants are fed through a drip irrigation system. Part of the drip system includes the use of a proportioner or injector. Three stock solutions feed the injector, which dilutes in the correct ratios the concentrate stock solutions into a blending tank where water is mixed to produce the final plant nutrient solution (Photo 9). The stock tanks are 75 times normal strength that the plants require, so as it enters the blending tank, it is diluted with 75 parts of raw water to get the correct final solution. We use an injector system to save us time in making up the nutrient solution. Without the injector we would spend a large part of the day making up the nutrient solution or require a very large cistern to store it. Every time we make up the stock solutions, about every 2 weeks, we send a sample to a laboratory in the U.S. for atomic absorption analysis. This gives us a report of the concentration of each of the plant essential elements and from that we can adjust the nutrient formulation to be within the correct concentrations and ratios of each element.

 

7. Purpose of the Hydroponic Farm:

The hydroponic farm was constructed to produce vegetables as part of a health conscious diet at Cuisinart Resort & Spa. The purpose was not to save money by growing our own vegetables, but to provide the guests with fresh “backyard garden” flavored produce (Photo 10). All the hydroponic vegetables are grown with the optimum levels of nutrients for the plants. This enables the plants to produce a very superior quality of products. The vegetables are harvested at their fully ripe stage so that the plant can synthesize all the vitamins and minerals it is genetically capable of. Tomatoes are picked as vine ripened, fully red, so as to obtain the best flavor and nutrition. This differs from most field tomatoes that are picked green and gassed with ethylene to turn them red.