For the Trial 2 experiment schools will use the same cultivars as in the previous trial. Prior to beginning Trial 2 all materials, including the wicking material, must be washed it in a 10 % chlorine solution. To extend the harvest time and increase the biomass production of produce you will extend the trial to 50 days by removing mature leaves for consumption on a weekly basis.

​

I.  Please review the protocol Trial 1.

• Prepare your media and plant your seeds and randomize as described in the Trial 1. Use the 50 day trial spreadsheet for this trial.

• Maintain and measure your plants and record all the data like in the previous trial. (In addition record the number of leaves weekly.)

• Update your spreadsheet weekly and keep a hard copy in your classroom.

 

II. Measuring/Data Collection

The following data should be collected weekly

• Number of leaves

• Plant height from media surface in tenths of a centimeter

• Plant width from left to right in tenths of a centimeter

• Plant width from front to  back in tenths of a centimeter

• Plant health

 

III. Harvesting

When the leaves of a plant start to obstruct the neighboring plants, it is time to start harvesting your leaves. Depending on the cultivar, most plants will be ready to harvest by week three. To determine which leaves to harvest

​

1. Look at the base of your plant where the rosette starts or where leaves appear from the soil and determine the oldest leaves.

2. For most varieties, the larger outer/older leaves (outer rosette) can be harvested by carefully clipping the leaves of the outer rosette. Leave the smaller inner leaves to grow further and to be harvested at a later date. If leaves are growing from a stem, harvest the lower leaves by cutting them of the stem.

When plants are ready to harvest, you must record the following on your data sheet:

• Number of leaves removed from the plant

• Weight of total edible fresh mass of the removed leaves

​

Remember to keep all the information, including the plant positions, in a hard copy lab notebook to refer back to if needed.

 

IV. Final harvest

On the day of the final harvest (Day 50), measure your plants as usual and record the weight of fresh mass and edible mass to the spreadsheet.

• Edible mass is all the plant mass you would be able to eat, sometimes including the stem but not dried or spoiled leaves.

• Fresh mass is the total mass of the plant. Fresh mass is measured by cutting the plant from the pot. The plant must be dry (do not wash or wet the leaves before weighing)

• Do not include media or roots with your measurements; however add root growth observations to your spreadsheet.

 

Link to PowerPoint presentation.