[Plant-education] Re: Intro to Greenhouse Lab

David R. Hershey dh321 at excite.com
Sun Aug 27 18:48:53 EST 2006


What length of lab are you looking for and is the greenhouse going to
be used extensively for student projects?

Many greenhouse labs take weeks because students grow crops. The
students often set up most of the projects early in the semester so
they have time to grow. Some examples would be
1. Grow a crop of chrysanthemums or poinsettias so students gain
experience with photoperiod control, irrigation, fertilization,
pinching, growth regulator application, etc.
2. Root cuttings
3. Germinate seeds and grow a crop of bedding plants
4. Air-layer overgrown houseplants
5. Force bulbs such as daffodil or tulip
6. Hydroponic experiments, such as producing mineral nutrient
deficiencies/toxicities
7. Comparing plant growth with different levels of light, water,
fertilizer, salt, soil pH, etc.
8. Comparing plant growth with different types of soil or fertilizer
9. Comparing plant growth with and without biological nitrogen fixation

Starting with rooted cuttings, the first project would take about 3
months and would require students to revisit the project frequently and
someone to take care of the plants on a daily basis.

For a first lab, students may just receive an orientation on their
greenhouse experiments for the semester and the greenhouse procedures,
such as sanitation, irrigation and fertilization methods, etc. and then
just pot some plants, bulbs, seeds or cuttings for one or more of the
long-term experiments.

A single 1-3 hour lab could involve student measurement of potted plant
transpiration or photosynthesis under greenhouse versus outdoor and lab
environments. Transpiration can be measured cheaply with a balance. Tie
a plastic bag around the stem to prevent evaporation from the pot and
soil surface. There are photosynthesis systems for teaching or the
inexpensive leaf disk method can be used (see reference). It would also
be worthwhile for students to measure light levels in those three
environments so they could correlate their transpiration/photosynthesis
data with the light level.

Another way to introduce greenhouses might be a tour of a good
commercial, university or botanic garden greenhouse.


David R. Hershey
http://www.angelfire.com/ab6/hershey/bio.htm

Reference

Exploring Photosynthesis with Fast Plants
http://www.fastplants.org/pdf/activities/exploring_photosynthesis.pdf


Robyn Wolin wrote:
> Hi,
>
>   I am starting to prepare my syllabus for my HS class of Intro to  Botany.  In the first few weeks of school I am looking to do a lab  to Introduce the greenhouse to the students.  Does anyone have a  good lab to introduce the greenhouse?
>   
>   Thanks,
>   Robyn



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