Sustainable Indoor Gardening
to support Science Education in the classroom.
Indoor gardening can be a great way for
primary school educators to integrate their science instruction with fun hands
on activities. Students can use indoor
gardening to develop hypothesis, collect and analyze data ,
and work collaboratively.
Indoor gardening and food production can also be a great segway into
environmental issues such as fertilizer runoff, storm water management, and
carbon sequestration.
Indoor gardening can be done effectively
using recycled materials, often called “upcycling” where the recycled materials
are put to a higher use. One basis for indoor
gardens is the two litter soda bottle
planter, a type of SIP (Subsurface Irrigation Planter) that is free and easy to construct. Advantages of SIPS over regular pots include
less water stress on plants, no
fertilizer runoff, no weeding, and
dramatically less watering . Wooden
racks can be made from pallet crates to prevent the planters from falling over
as the plants grow.
Once you have constructed your 2-Litterbottle SIPS you may want to use a local sustainable potting mix made from
Biochar (horticultural charcoal) and compost. Biochar has a two thousand year history of
use in the Amazon region and is locally known as Terra Preta or “dark Earth”. It’s beneficial effects on
plants include: increased retention of
nutrients, soil aeration, and better habitat for soil microorganisms. Biochar represents a simple way people can
take excess Carbon Dioxide out of the air and put it permanently back into the
soil where it helps grow food.
Indoor gardening does require artificial light
to produce healthy plant growth. Do not
expect strong food production from plants placed under a window, even a south-facing
window. The solution is simple fluorescent
lighting placed within two inches of the plant leaves, raised occasionally as
the plants grow taller. Inexpensive shop fluorescent lights can be
used. A simple timer set for 16 hours on, 8 hours
off produces strong, healthy growth. Note if warm weather is available SIPS do
great outdoors or on a rooftop.
Once your SIPS are filled with potting mix
you can fertilize them using organic compost tea or slow release inorganic
fertilizer. If using slow release inorganic (Ex
.Osmocote, or Miracle Grow slow
release) cut the recommended dose in
half. If using compost tea fertilize
every other watering.
Crops like lettuce or basil are well suited
for the classroom and can be produced within 45 days. Lettuce is best if your building runs on the
cool side ( ess than 70 F and basil
is suitable if temps stay above 70 F).
Seeds can be planted directly into the planters and germinate quickly.
Here are some ideas for integrating
science into gardening:
Design an experiment to test out a variable
such as light level, fertilizer
concentration, salinity of water, pH of soil,
commercial vs biochar mix, air
temperature, music, specific soil ions like calcium, sodium or potassium. Rainwater can be compared to tap water. There are many possibilities.
Students can measure the diameter and
height of the plants over time,
integrating math into the activity.
Hopefully your students will come to
appreciate how easy and rewarding it can be to grow good food. The secret is in setting them up for success
using proven techniques like sub irrigated planters. Best of all, you get to eat your
experiment!
The biochar mix can be reused in the
end. Remove the mix and break up the rootballs, composting the roots. Refresh the biochar mix by adding 10% fresh
compost by volume. Rinse out the
planters and add the refreshed biochar mix.
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