Activity - Buried Treasure? Weed Seed Bank

Skills: Observing, measuring, predicting, recording data, reasoning
Activity - Buried Treasure? Weed Seed Bank - Articles
Activity - Buried Treasure? Weed Seed Bank

Introduction:

We tend to think of weeds only when they "show up" as big vigorous plants swallowing up our gardens. However, weed seeds are like little time capsules, living in the soil over long periods of time, waiting for just the right conditions to germinate.

Learning Objectives:

1. Understand the unseen parts of a plant lifecycle
2. Understand that different habitats harbor different seed life
3. Discuss the implications of this to weed management
4. Learn that there are varying characteristics of weeds.

Materials Needed:

Shovel or trowel for digging up soil and flats to put the soil in.
Optional: Different types of mulch to do an experiment.

Timeline:
10 minutes a day over the weeks of observation

Procedure:

1. Dig up some soil from 2 or 3 different habitats - students can bring soil from their yard, garden or farm fields. Also include some soil from undisturbed natural habitats.

2. Fill up two flats with each kind of soil; one flat will be watered only. The other will we watered and then covered with some kind of mulch (grass clippings, plastic, paper)
Label each flat as to the kind of soil and date of watering.

3. Make a data sheet for each flat. Have the students form hypothesis of which flats they think will:

a) germinate first
b) have the most plants
c) have the most different kind of plants
d) have the most competitive plants (crowd out the others over time)

4. Keep flats moist but not soggy. Wait for seeds to germinate.
5. Once seedlings start to emerge, have the students begin to take data.

Analysis:

Depending upon the age of the students, the concept of diversity can be discussed and/or calculated. Students can identify which flats

Discussion:

Have students discuss the management implications of their observations or experiments. From a weed management point of view, one of the best strategies to prevent long term weed infestations is not allowing the weeds in your farm and garden go to seed. Mulching before seeds can germinate is another option (but does not work as well on plants that send out "runners" or "rhizomes").