After several weeks of meeting to weed and water, we finally got to harvest vegetables this week. Students had been watching the progress of the vegetables during recess breaks so they knew that we would finally harvest the green beans. They had also seen one beet protruding from the soil and knew that the radish leaves were large and dark green, but hadn’t seen the radishes yet. One of the younger students had never harvested anything before so she was especially eager to get the harvesting process started.
We had good luck this year with green beans. There was very little damage from caterpillars, and the weather has bean cooperative. Students all participated in pulling the beans from the plants, filling a large plastic bag. The remaining bean plants were thrown into the compost bin. Our row of beets did not do as well. Only one beet matured, although another 3 or 4 have sprouted and are beginning to develop leaves. We also had one cantaloupe waiting to be harvested.
The radishes were the big surprise since students had never seen Japanese radishes before. Although they had seen the seed package when they planted the seeds, they had forgotten the picture on the package. When they pulled out long white radishes that looked more like white carrots than radishes, they were shocked. We cleaned, peeled and sliced one radish, so they had a chance to taste it. Most of them had never tasted a radish of any kind before but they all gave it a try. The first taste is sweet but there is a peppery aftertaste which they liked
We divided up the beans and radishes for the students to take home. Three of the students gave their radishes to me to take home after I explained that I had enjoyed eating pickled radish in Japan. I will pickle it using the recipe from the Food Network for Sweet Pickled Daikon Radish and will take it to school for the three of them.
It was a busy day. We also thinned out the carrots and tomatoes. Some of the tomatoes were transplanted to the square garden frames near the early childhood classrooms. They will be happy to see them tomorrow when they arrive at school.
We planted our bean seeds on Friday, Sept. 21. For some seedlings, the cotyledons are just breaking through the surface of the soil. For others, the first leaves are already developed and a dark green color. The seed package says the average germination time is 7-14 days, so we’ll have more sprouting in the next week. We should have fully grown plants with new beans to harvest in early November.
I marvel at the germination process each time I see it. As the cotyledons push out of the soil, the roots grow down into it. The roots absorb water and minerals from the soil while photosynthesis in the tender young green leaves traps the sun’s energy for use by the growing seedling.
“Everything growing from the earth, bless the Lord; praise and exalt him above all forever.” (Daniel 3:76)
Dissected seed showing the cotyledons, first leaves and first root.
First leaves developing between the cotyledons.
The dark green color shows that photosynthesis has started. The nutrients in the cotyledons are almost gone.
Students spent a few minutes on Thursday observing their beans and doing some weeding. Our beans are looking good. The beans in the photo were planted 3 weeks ago and are green and healthy. In the rows on either side, students saw that the seeds they planted a week ago were germinating and pushing through the soil to the surface. Since we had just talked about roots, stems and leaves in the classroom, it was fun to put that into immediate practice. I told them to pull the weeds up by the roots. They were amazed at the differences in the root structure of various plants and the depth of roots compared to the number of leaves and heights of the plants.
We’ve had a weekend of steady rain since the photo was taken. I wonder how the garden will look tomorrow?
Place 10 seeds in a pot with soil. Cover the seed. Repeat for 3 other pots.
Label the pots 1, 2, 3, 4.
Water pots 3 and 4.
Place pots 1 and 3 in the light.
Place pots 2 and 4 in the dark.
Observe for 10 days
The purpose of the experiment was to help students understand that light and water are needed for growth of a healthy plant. The need for light was easy to see. Although the plant in sunlight with water (see image below) was long and spindly, it turned green, developed leaves and lived longer than the other plants. The plants in the dark stayed white, withered and died.
The surprise to all of us was how many of the seeds germinated in the dry pots – as many as germinated in the pots with water. In fact the seeds in the dark cabinet germinated best of all. The pots in the dark were in a cupboard under a sink. We determined that the pipes had water condensed on the sides, so there was more moisture in the air than we realized, and of course the classroom air in Florida in the summer is humid – with so much moisture that the seeds had a very good environment for germination.
The experiment lead to a discussion about the fact that different seeds have different requirements. We’ll come back to the idea later when we discuss ecosystems.
Students were amazed at how fragile the embryo was and how easily it fell out when the cotyledons were separated. Students summarized what they knew about requirements for seed germination. We also discussed why it was important to correctly and gently handle the germinating seeds and the seedlings. Students also wondered if the seeds would still germinate and grow if the embryo was separated from the cotyledons. Some came back to revisit this question when they developed their seed germination experiments a few classes later.
Classroom note: Iodine + starch produces a blue-black color and is used as an indicator for the presence of starch. Many bean seeds contain protein, so not all bean seeds will pick up the iodine stain. The blue-black color highlights the embryo, and makes it easier to distinguish the embryo from the cotyledon.