Role of Teacher
Materials: Gloves (for each student) / Wheelbarrows (optional) / Small shovels and trowels / Large shovels and rakes / Cover crop seeds / Watering cans (5-10)
- Putting the garden bed “to sleep” is a very important part of the gardening calendar. The plants that have been being harvested all fall took many nutrients from the soil, and now the soil needs to be replenished during the winter, before the next growing season.
- Cover crops, also known as “green manure” to experienced farmers and gardeners, are crops sown in the late fall to provide cover and nutrients for the soil during the winter when nothing is growing in the garden. There are many different types of cover crops including rye, wheat, clover, barley, oat, buckwheat, and hairy vetch. While some of these cover crops sound like foods we’ve eaten before (i.e. oats, barley, rye, etc.) cover crops are generally not harvested, but rather tilled back into the soil at the end of the winter and left to decompose in the soil, thus providing more organic matter and nutrients to the garden.
- Cover crops are beneficial for many reasons! Because many cover crops are legumes, they fix nitrogen in the soil as they grow. Then, when tilled back into the soil at the end of winter, they provide organic matter and even more nutrients. Cover crops also help suppress weeds by taking up all of the space where weeds would normally want to grow during the off-season. Many cover crops provide nectar and attract pollinators, which help deter many pests and reduce the need for chemical pesticides. The roots of cover crops help reduce soil erosion by holding on to the soil during heavy wind and absorbing much moisture during periods of heavy rain.
Topics / Goals / Learning Objectives
- To continue to understand what cover crops are and why they are used.
- To recognize the different types of cover crops.
Opening / Hook
Welcome to the garden! Last week we learned about why we use cover crops and went over a few of the different kinds of cover crops used by farmers and gardeners all over the world. Can anyone remind me what cover crops are and why we use them? (Allow time for brainstorming and answers.) Can anyone remember 5 different kinds of cover crops we went over? (Allow time for brainstorming and answers.) That’s great!
Today we are going to put everything we learned about last week into practice. But before we sow our cover crops, what do you think we need to do first to make room for them? (Allow time for students to look around and brainstorm.) That’s right, we need to clear the beds so that they have room to grow. What do you think we’re going to do with the plants that we remove today? Yes! We’re going to compost them! Who can tell me what compost is? (Allow time for brainstorming and answers.) Just like compost is a natural fertlizer for our beds, so are cover crops.
We are going to break up into four groups. One group is going to be taking the old plants out of the beds and bringing them to the compost, one group is going to be continuously digging them into and turning the compost, the third group is going to broadcast cover crop seeds and last group is going to water them. Does anyone know what the term “broadcast” means? (Allow time for brainstorming.) Broadcasting means to cast a handful of seeds over prepared ground, rather than digging a hole and placing a seed in it. We broadcast cover crops because they do not need specific spacing, can grow randomly and can grow in much greater numbers. On the other hand, we space tomato seeds at least 12 inches apart because they need lots of room for their roots, stems, leaves and fruit to grow. So before we broadcast, we will have to loosen the clread beds with our shovels and rakes. Then, when we water the seeds, they will sink deeper into the soil and won’t be at risk for blowing away. Let’s begin!
Procedures / Activities
- Welcome students to the garden and introduce the lesson with the Opening above.
- Break the class into four groups. As explained to them above, have one group taking plants out of the beds and bringing them to the compost. Have one group (this should be the smallest group of about 2-3 students) continuously digging those plants into the compost. The third group will loosen the soil in the cleared beds with their shovels and rakes, and then broadcast the cover crop seeds. The last group can fill their watering cans and water the broadcast seeds.
- Continue working until the desired amount of beds or garden space is cleared and the cover crops are broadcast and watered.
- Before the end of class, gather around in a circle and discuss what the class thinks the cover crops will look like. What, for example, does hariy vetch look like? Clover? Buckwheat? Tell them that in a few weeks we can come back and see if our predictions are correct.
Extensions / Adaptations / Games
End with a tasting of the bread they baked the previous week or with a tasting of the last harvest of whichever plants were being cleared out of the garden (i.e. tomatoes, basil, kale, etc.).
Credit for Adaptation
Broadcasting Cover Crops, Edible Schoolyard Pittsburgh. www.edibleschoolyardpgh.org