October in the Edible Garden
October is here and it’s harvest season. But it is so much more. Many of us are coaxing fall plantings along, trying to extend the gardening season. If you are finished for the year then you may be doing cleanup, adding compost or mulch to your soil, or planting a cover crop to keep living roots in the ground through the winter. It is also a good time to reflect on the past growing season to extract lessons that will help you improve your results next year.
Looking back, the weather has been a real challenge this year. With late frosts, a dry, scorching July and a very wet August, it has been a challenge to keep plants healthy. As I write in mid-September, temperature and moisture have moderated and my fall vegetable crop is growing pretty well. I’ve expanded my vegetable patch for next year and plan on seeding a mixed cover crop shortly to add some organic matter and structure to our native orange clay. I’m also getting ready to put row covers over my fall greens to help keep them healthy and growing into the winter. Walking out to the garden to cut fresh kale or salad greens in December is its own special reward.
Whatever your situation, enjoy the cooler weather, the fall colors, and the prospects of a fresh start next spring.
If you planted crops for fall harvest last month, you may already be harvesting fast-maturing plants like some lettuce greens and radishes. According to the VCE Vegetable Planting Guide, those of us in Hardiness Zone 7a are still able to plant radishes, mustard and spinach as late as mid-October. That’s cutting it close, but if the warm weather we’ve had so far this year continues, there is a good chance of success. On the other hand, this year’s weather has been unpredictable, if it’s been anything. For the record, the average first frost for Zone 7a is October 15-25. Be sure to keep your eye on the weather and bring in or protect your warm weather crops when that first frost comes around.
To get a better understanding of frost damage and which vegetables are or aren’t susceptible to it, refer to the article Identifying and Preventing Freeze Damage in Vegetables from the Michigan State University Extension.
Obviously, harvesting ahead of frost is a sure way to avoid frost damage. If you want to nurse plants further into the fall, there are a couple of options:
- Wet your soil: there is some evidence that watering ahead of a frost will keep the air temperature just above the soil up to 5 degrees warmer than dry soil and will maintain the differential overnight.
- Cover your plants: If you are looking for more certainty, cover the crops that aren’t cold hardy. Spun polyester row cover fabric is a proven choice, although gardeners use everything from newspapers to buckets to commercially available water-jacketed individual plant covers. Fabric cover protection varies from 2 to 6 degrees Fahrenheit depending on soil conditions and fabric used. Air space between cover and plants increases the protection vs laying the cover directly on the vegetation. Spun fabric covers let light and water through and can be left in place. Most other options need to be removed during the day after the temperature is above freezing. For more information on row covers please check out the Garden Shed article: Row Covers: A Season Extender with Benefits.
- Cold Frames: For a more permanent way to combat both spring and fall frosts, consider building a cold frame. Tips on construction and on using cold frames are available in the Virginia Cooperative Extension publication titled Season Extenders.
Other October Tasks:
- October is the time to plant garlic and shallots for harvest next year. Check out this September 2015 Garden Shed article titled Garlic for guidance.
- Harvest tender herbs (basil) before the first frost. They can be hung to dry in a cool dark place or the leaves can be frozen for use at a later time.
- If you are thinking about planting a fruit tree, fall is the time to plant. You may be able to save a little money by catching a sale at local garden centers. Water the newly-planted tree thoroughly to provide sufficient moisture and prevent winter damage. Add a 3-inch layer of organic mulch, leaving a 3-4” gap around the tree base, to retain soil moisture and moderate soil temperature. Research has shown that roots will continue to grow until the soil freezes, which is typically late November in Virginia. Stake and wire newly-planted trees only if necessary. Use a piece of rubber hose around the guy wires to protect the trunk. The guy wires should be tied loosely enough so that the tree is able to move a little in the wind. The supports and stakes should be removed once the tree becomes established, usually in a couple of months.
- Pick up dropped fruit from under fruit trees so that deer and rodents will not be attracted to the fruit or your growing tree. Raking and disposing of diseased leaves will help keep insects and diseases under control next season.
- High grass and mulch are a haven for rodents whose gnawing can severely damage trunks. Keep the grass mowed around new trees. Be sure that mulch is raked back 3-4 inches away from the base of the tree.
- Tomatoes need an average daily temperature of 65º F or higher in order to ripen. If daytime temperatures are consistently below this temperature, pick the fruits that have begun to change color and bring them inside to ripen. Placing them in a paper bag with a banana or two will speed the process.
- Harvest sweet potatoes before frost because cold soil temperatures can reduce their quality and storage life. Removing the vine first can make the digging a lot easier. Also, take care when digging sweet potatoes because their skin can bruise very easily.
- When removing disease-infested plants or debris, do not place this refuse on the compost pile.The disease pathogens may continue to live in the compost pile and be transmitted when the compost is applied to the garden. Best to burn or bag and landfill it.
- After frost, cut back asparagus foliage to within 2 inches of the ground.
- There is still time to plant a cover crop. A cover crop protects the soil over the winter, stores unused nutrients to prevent them from leeching, and adds organic matter in the spring when tilled under. These Garden Shed articles from September 2015 and August 2017 can provide guidance.
- If you aren’t into cover crops, or wait too long to plant, cover the garden soil with a few inches of mulched leaves or aged wood chips. Mulch reduces nutrient leaching and carbon loss and moderates temperature variation.
- If you haven’t kept up with garden documentation, this is your last chance. It’s a good idea to diagram the garden along with specific crop locations. Crop rotation is an important organic tool for minimizing insect and disease issues passing from one season to the next.
- Vegetable crops in the same botanical family are often susceptible to the same diseases and insects. For crop rotation to be effective, gardeners should not plant vegetables belonging to the same family in the same location for at least three years. Crop rotation in a small garden may be difficult. However, we should rotate our vegetable crops as best we can.
Thanks for stopping by The Garden Shed; we look forward to your visit next month.
Virginia’s Home Garden Vegetable Planting Guide, https://www.pubs.ext.vt.edu/426/426-331/426-331.html
Phillips, Ben and Collin Thompson, “Freeze Damage in Fall Vegetables: Identifying and Preventing,” http://msue.anr.msu.edu/news/freeze_damage_in_fall_vegetables_identifying_and_preventing
October Tips: Fruit and Nuts: https://albemarle.ext.vt.edu/content/dam/albemarle_ext_vt_edu/files/hort-tip-sheets/10-14-fruit-nuts.pdf