Q. Can you recommend a fall-sowing cover crop for Northern Illinois that I can turn over in the spring?
A. Cover crops, also known as green manure crop, can be grown during a season when the garden is not in use, usually fall and winter. In the spring, the crop is tilled into the soil to improve the fertility, as well as to improve soil tilth and texture. The key is to let them grow, and before they flower and go to seed, till them in to add the organic matter.
Cover crops such as oats, buckwheat, annual ryegrass, hairy vetch, medium red cover and winter rye can be grown in the fall in the Midwest, and tilled in the spring. Plant seed at least four to six weeks before cold temperatures set in. Keep the soil moist until germination occurs.
Seed cover crops can be purchased from a local farm supply store or garden centers. For small gardens, better to use a mulch such as straw or leaves than a cover crop, as the work to kill and till in the cover crop by hand is not usually worth the worth the effort.
Q. Last fall I put several inches of mulched leaves on my garden to add nutrients to the soil. In the spring the layer of mulch kept the soil from drying and it was late spring before I could dig the garden. Is there a better way to use the mulch in the fall?
A. Your idea to replenish soil nutrients with mulched leaves is good. Try digging your garden in the fall by doing the following:
• Thoroughly remove all plant debris that might be infected with fungus due to our wet summer.
• Add 2-4 inches of shredded, disease-free mulched leaves onto the garden. You can shed them with a lawn mower. To help leaves break down further, add 10-10-10 fertilizer at rate of one pound per 100 square feet.
• On a nice day in November or December, dig the garden mixing the leaves into the soil, breaking up only the large clumps of soil.
The winter freeze/thaw cycles will help break up the clumps of soil into finer particles. Likewise, by digging in the fall you are exposing buried nuisance insect egg casings to the hard freeze. When the soil dries/warms in the spring, you should be able to rake it into fine till without strenuous digging.
If it's still too wet, try creating a raised bed.
Q. Last spring I found many brown needles on some of my evergreens. I think it was a type of "winter burn" due to strong cold winds. How can I prepare my evergreens to avoid that problem this year?
A. It sounds as if your evergreen needles were damaged during the severe winter. Cold winter winds and sun can quickly desiccate (dry out) evergreens. It is particularly important that all evergreens (needle and broadleaf) are well watered before freezing temperatures. On broadleaf evergreens such as holly, boxwood, and rhododendron, you will find browned foliage if the plants suffered winter damage.
Plants in exposed areas can be wrapped in burlap for winter protection. If you have too many evergreens to cover with burlap, you can spray them in late fall (when temperatures are above freezing) with an anti-desiccant available at nurseries.
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