I love putting the garden to bed in the winter. It feels good to offer back to the soil after a long season of harvesting. The best way to do this is to add compost to garden beds and to plant cover crops in the late fall.
Cover crops are cold hardy plants that provide various benefits to your garden soil most importantly by adding organic material back into the soils. In the spring the crop is chopped up and incorporated back into the soil. Simply put, this organic material improves soil structure, increases water retention and drainage and provides necessary food for earthworms and microorganisms in the soil.
Legumes such as bell beans, hairy vetch and crimson clover, have an amazing symbiotic relationship with the rhizobia bacteria on their roots, and are able to convert atmospheric nitrogen into a form plants can use to grow. Some cover crops like Winter Rye can be grown to prevent erosion . A single Winter Rye plant (Secale cereale) has been shown to produce 387 miles of roots and 6,603 miles of root hairs in 1.8 cu ft of earth!!! That’s a fact sure to impress your students!
Certain cover crops, such as bell beans and oilseed radishes, have aggressive taproots, sometimes reaching 3 feet deep, that help break up compacted soils. The taproots also “mine” nutrients such as calcium from deeper soil, and when the plant dies, the nutrients are released in the root zone for the next crop.
When cover crops, such as crimson clover and mustard, are allowed to flower, they attract bees and beneficial insects that help with pollination and insect control in the garden and provide you with lots of places for bug patrol in the early spring with students!
I like to plant different types of fava beans like the Crimson Flowering Fava or the Tarma Spiral which both fix nitrogen in soil and can also be eaten in the spring! You can under sow with CA Poppies or Crimson Clover for beauty and for pollinators! Plus you can save seed from these crops in the spring! Cover Crops are a lot of fun to plant with students. Because most of them are inexpensive, particularly the “Green Manure” blends, it is the one time I relax a bit and give them handfuls of seeds! To make your garden more interesting you might try different combinations of cover crops and then compare soils in early summer with a soil test kit or in a plant growth experiment.
Winter wheat is another interesting crop to put in at this time of year. Wheat can be harvested in the late spring. Students can learn how to winnow and thresh the grain. A 3×10 foot bed will not produce much grain and you will likely need to supplement to actually cook something with it, but it is a great full cycle activity. Of course , you can link to Little Red hen with primary grades or grow a historically significant variety like the Sonora Wheat and link to social studies. School Garden Network has a hand crank grain grinder that we can bring out to your garden to turn your grain into flour. Perhaps we could make some pancakes in the garden with your grain!