Thursday, April 12, 2007

The Path of Specialty Lettuce, Part Two

On Day 11 of the growth process of our Specialty Lettuce, the day temperature of our 5500 square foot greenhouse is set at 24º C (75º F) from eight in the morning to six at night. Just before our day staff leave at 6pm each night, the temperature in the greenhouse automatically drops to 19º C (65º F).

Our three greenhouses are set to run automatically, but we still have an employee on duty at night to make sure that all goes smoothly. Chuck and I often drop in at night in order to safeguard our investment.

All of the Red Sails and Green Ice plants in our Specialty Lettuce greenhouse have been moved to the Nutrient Pond by Day 11. The nutrient solution in the pond consists of purified water with our main fertilizers, Advanced Nutrients Grow and Micro, as well as all the additives, supplements, and root colonizers called for by the Nutrient Calculator on that company’s website.

The pH of the Nutrient Pond should always measure 5.8. If there is any deviation, a valve opens on a side tank and small amounts of pH Up or pH Down are added to the Pond, depending on which way the correction is required.

The total dissolved solids (TDS) of the solution is 1200 parts per million (PPM), or 1.71 EC. To give you an idea of quantities, our Nutrient Pond contains 2000 Liters of liquid. Dissolved in the solution are 3200 mL of Micro, 3200 mL of Grow, 4500 mL of Mother Earth Super Tea Grow, 2500 mL each of Humic Acid and Fulvic Acid, 12500 mL of B-52, 374 mL of Barricade, 20000 mL of Scorpion Juice (once every three weeks), 12500 mL of SensiZym, and during week 11 and 12 only 600 grams each of Piranha and Tarantula, topped off by 3000 mL of Voodoo Juice.

When we stop adding the root colonizers, we adjust the quantities of the other ingredients accordingly, to maintain a uniform ppm level. We also add Sensi Cal Mg Grow, which completes the total dissolved solids picture.

We never add Bloom into the mix, since we don’t want our lettuce to bolt and go into flower and seed production. Just to refresh your memory, on Day 11 our Specialty Lettuce plants are situated in the middle of Styrofoam squares that are floated on our Nutrient Pond.

By Day 18, the leaves of our lettuce plants have grown to cover most of the Styrofoam floaters. The roots have grown into the solution extensively (especially after being treated with the root colonizers) and the surface of the Pond is entirely covered with either green or green with red borders heads of lettuce.

By Day 21 the lettuce leaves are overlapping and re-spacing is necessary. Additional Styrofoam squares are added as spacers in between the head of lettuce on the Pond, to reduce the number of plants from 90 per square meter to 35 per square meter.

By Day 32 the Pond is completely covered with lettuce plants, but the leaves are not overlapping and there is adequate room for each plant to develop to its fullest capacity.

Day 40 is Harvest Day, and each head of Specialty Lettuce should weigh 5 oz. (150 grams). These last days of growth will eventually be reduced so that it will take 35 days from seed to harvest, rather than the 40 that it will take initially.

Harvesting will take place early in the morning to take advantage of the cool temperatures, and the 600 heads of leaf lettuce per day will be packaged and stored in the harvest room of the greenhouse, in which the temperature is kept at 0º Celsius. The cooling will ensure that the lettuce will stay crisp and crunchy, until it gets to market.

We store our lettuce in polyethylene head wraps that have ventilation holes in them so the plants can breathe. The individual heads are carefully placed in boxes and taken to local supermarkets as quickly as possible. So the lettuce that we pick in the morning will be on neighboring store shelves after lunch.

It is important to market freshly picked lettuce the same day, even though with cooling and proper storage Red Sails and Green Ice lettuce can stay fresh for 3 or 4 days. With consumers becoming ever more conscious of healthy eating, we pride ourselves on delivering fresh, crunchy, extremely tasty produce from our hydroponic Nutrient Pond to your table as quickly as possible.

Lettuce should never be stored with apples, pears, tomatoes or other produce that give off ethylene. Ethylene can cause russet spotting on midribs of lettuce leaves. A great trick for reviving slightly wilted lettuce is to place it in ice water. This treatment will restore its freshness and crunchiness.

One of the reasons that our lettuce is so crunchy is because we feed both our Specialty Lettuce and our Butter Lettuce with the micronutrients of Sensi Cal Mg Mix Grow. Calcium is the secret ingredient in lettuce crunchiness, and Magnesium is necessary for the absorption of Calcium.

Sensi Cal Grow has Amino Chelated Calcium, which is the highest quality available and is readily absorbed by our lettuce plants. But it also has four other forms of Calcium (Calcium Acetate, Calcium Chelate, Calcium Nitrate, and Calcium EDTA), as well as compounds of Boron, Cobalt, Copper, Iron, Manganese, Molybdenum, Zinc, and the aforementioned Magnesium.

This full spectrum of micronutrients means that there is no lockout of Calcium or Magnesium. The ingredients of Sensi Cal Grow are all pharmaceutical grade precursors and reagents, as well as high quality chelators. It is the best quality product of its kind on the market.

Calcium is essential for both humans and plants. Our Butter Lettuce has benefited from our use of Sensi Cal Grow for a number of years, and now our Specialty Lettuce can look forward to a crunchy future, thanks to this excellent Advanced Nutrients product.

posted by silvio @ 5:08 PM   1 comments


At 2:14 AM, Anonymous Anonymous said...

wow, this was extremely informative.

can you please post some pictures of your nutrient pond and styrofoam setup? sounds very cool. do you use HID lighting? can lettuce be done under flourescents? i want to do something small for salads and sandwiches. butter lettuce and mesclun maybe. do you clone these? or do you do them all from seed? where do you get your seeds from?



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