Tuesday, March 20, 2012

Lunch scraps, the FBI, and Humus

Spring is on the way and that means a long list of gardening chores.  Before the children prep the beds for planting, we need a good supply of humus.  Because each class has been contributing their snack and lunch waste since September, we have a ready supply at hand.  We just need to separate the finished humus from the material which is still decomposing.

Compost is simply organic material that has decomposed.  It is essential to organic gardening because it returns nutrients to soil.  Humus is the finished product used as a soil amendment. 

We use a system of screens made from nursery plant trays and trays from a worm bin.  The first screen set has large openings and the second screen set has smaller holes.

The children scoop material from the compost bin into the first screen set.  With a little shaking, the smaller pieces fall to the tray.  The larger pieces remaining on the screen get returned to the bin to continue decomposing.
The first tray is poured onto the second screen.  A little more shaking and the humus falls down through the small holes to the tray. 
The children felt the finished humus and compared it to the original compost material.  The humus was described as "small" and "crumbly". 

When they looked at the humus, they could not tell what it had been, but the compost material still showed pieces of banana and orange peels.  They are able to see that the unused food was not wasted, but is now providing nutrients to the garden.  This practice is one method of teaching the concept of bal tashchit.

Here's a little video of a member of the FBI; fungus, bacteria, and invertebrates.  They are the allstars of decomposition.

February Surprises

 This is what February in Dallas looks like.  At least for one week during 75 degree days.   The tulips were planted in December anticipating a beautiful show in April.  Alas, it is now March 18 and only stems remain.  They were beautiful while they bloomed, even if it wasn't on my schedule.  But, that is what gardening reminds us.  We are not in control.  G-d through nature continuously brings unplanned and unexpected surprises.

After the beautiful,  sunny days, came the rains.  And I had a few surprises for the students.  We donned rain ponchos, grabbed our hand lenses and went exploring.

Some of the leaves collected water drops.  This cabbage leaf looks like a swimming pool for a lady bug.

When the rain stopped, we found a big puddle in the parking lot.  I challenged the children to "think like a scientist" and make observations about the puddle.  Several children noticed that the surface of the water acted like a mirror.  They commented that they could see the trees and the building in the water.  One child noticed that the water was moving.  I asked her what was making the water move.  She watched for a moment and then answered, "the wind".

Finally, some noticed that leaves were floating on the surface.  I asked them if they could create an experiment using the puddle.  They gathered items found on the ground and conducted a sink and float experiment.  At one point a pansy was floating.  The wind caught it and moved it forward.  One child picked it up, then placed it back on the water.  But, it was turned upside down.  The children noticed that instead of floating, it partially sank.  After a period of discussion, they decided that it sank because it had water on top of the petals.  And water made it too heavy to float.