garden cleanup

Cleaning up the vegetable garden in fall

Maryland Grows2 Comments

With the first frost of autumn hitting many areas of Maryland, this is a good time to think about cleaning up your vegetable garden, if you haven’t already done so! Below are some hints to getting this job done efficiently and well, and some distinctions between the vegetable garden and the rest of your yard to keep in mind.

First, maybe you still have seasonally-appropriate plants growing – in which case, congratulations! Whether they are cover crops or cool-season vegetables, keep them watered as needed and remove weeds. We’re past the point where you have to worry about most insect pests, so the lightweight summer row covers can come off the brassicas, but you may want to replace them with heavier row covers to keep the plants a bit warmer and protect them from wind. You’ll have less frost damage that way, and can keep your veggies alive longer into the winter.

Summer vegetables, however, are toast. In some recent years we haven’t had frost until later in November, and I’ve seen lots of gardeners keep tomatoes and peppers growing up to Thanksgiving. My attitude is, why bother? You may still get some produce, but the quality and flavor will not be great, and then you’ll have to do cleanup when it’s really cold. Just pull the plug. Of course I have a small garden, and if I want to plant any fall veggies, the summer ones must vacate as soon as they start to go downhill. Your mileage may vary. But it doesn’t seem worthwhile to keep a sorry plant alive for just a couple of cherry tomatoes or a wizened paprika.

So, the first step is getting old plant material out. But wait, you say – didn’t I hear that we should leave plants in the ground until spring for overwintering insects? Sure, but not in the vegetable garden. Here are two good reasons why. First, when you leave perennial plants standing in your landscape so insects can find shelter inside their stems, you commit to waiting until the weather warms in late spring to remove the dead material. That’s going to be too late for vegetable planting in many cases, especially if you rotate crops and are planning to put a spring crop where your summer veggies grew this year. There’s a big difference between a landscape of perennial flowers and an ever-changing garden of annual vegetables.

Secondly, many vegetable plants are great disease hosts. Think about it – if tomatoes and squash didn’t produce delicious food, we’d probably banish them because of how awful they end up looking and how many fungi, bacteria and viruses they spread. The longer that diseased plant material stays in the soil, the more parts drop off and bury themselves, and in some cases that disease lives on until the next year, ready to infect a new host. Ideally you should remove sick plants, or at least the affected parts, as soon as they show disease. This is really hard to do in the middle of the growing and harvesting season, but if you haven’t caught up, at least do it now.

In general, diseased plant material shouldn’t go into home compost. Some fungal diseases will be killed by thorough hot composting, so if you’re rigorous you can take the chance, or else put it on the curb and let your municipal composting do the job. Consult our vegetable diseases pages for information about each type of infection – in some cases, you should just put the plant material in the trash. If you don’t know what infected your plant, it may be best to throw it out. If the plants have been healthy, you can shred and compost them, but remember to not add mature seeds to your compost. We’ve all had pumpkin vines and tomato plants emerge from our pile, and while it’s fun to have volunteers, remember that they may be cross-pollinated and unpredictable in what they’ll produce. Also, don’t add weeds that have gone to seed, or ones that have big roots.

Rake up the surface of your beds; get all that plant debris out. Then, the final step to putting the garden to sleep is covering the soil. If you haven’t planted cover crops, use some kind of organic material to keep the soil from erosion and sprouting weeds. You’ll be surprised how many weeds will cover those beds by spring! Many “winter weeds” have thousands of seeds to spread after they go to flower, so while the bees may appreciate the early snack they provide, you will not. Covering soil also helps to protect the beneficial microorganisms and other critters that inhabit it.

Fall is a great time to add compost to your garden beds, and if the compost is really finished its breaking-down process, it can be used by itself as a mulch. However, it’s probably better to protect it and limit its potential as a weed bed by covering it with other organic materials. Leaves, shredded or un-, are a great option, if you have them around. It’s less important to shred leaves for vegetable garden mulch than for perennial beds; it doesn’t matter that whole leaves mat down and stop young plants from getting through, because you’re going to remove them before planting anyway. Sometimes whole leaves blow away, though, so it’s your choice. Straw is another great option, either from a bale (make sure it’s straw and not hay, to limit the number of grass seeds that will sprout), or in a product often known as “sticky straw” which stays in place better (the “tack” will go away in time and the straw will decay nicely). Don’t make the mistake I did and buy the straw rolls that are held together with netting! Those are meant as a temporary cover for new grass seed. I guess I’ll pull mine up in the spring and maybe I can use the netting to keep the rabbits out of my lettuce bed.

You can also cover beds with a few layers of newspaper and then put leaves or straw on top, if you’re particularly worried about weeds popping up. Whatever lightweight organic material you have will be great, or you can also use black plastic or a roll of weed barrier as a temporary cover if you have nothing else. Plastic keeps the rain away from your soil, however, and it wants the moisture. And when the mosquitoes emerge again, they will breed in the puddles where the plastic isn’t flat.

Finally, fall is a good time to repair fences and fix or add other permanent garden structures. Do it now and you won’t have to do a rush job in the spring.

Then have a nice cup of tea or cocoa and put your feet up!

By Erica Smith, Montgomery County Master Gardener. Read more posts by Erica.

Native Solitary Bees: Don’t Make Your Landscape Too Tidy This Fall

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ground nesting bee on leaves
Cellophane Bee (Colletes thoracicus) is a solitary bee and valuable pollinator that nests in the ground. Photo by Hadel Go

Cooler evening temperatures might have you switching gears from planting and maintaining your landscape to fall decorating and garden cleanup chores. While cleaning up diseased and pest-infested plants in your yard and garden are important to prevent problems in the future, consider leaving healthy plants that could add visual interest this winter and provide nesting sites for many beneficial critters.

With more than 400 species of native bees in Maryland, these amazing little pollinators are a wonderful addition to your landscape. They are small and not aggressive. Some are specialists, which means they must have certain plants to feed on, while others are generalists and will visit a wide variety of plants. For amazing photos of native bees, check out the USGS Bee Monitoring Lab on Flickr.

As with all members of the animal kingdom, pollinators need food, water, and shelter in order to support life. Successful pollinator habitats include diverse flowering plants, food resources, and safe spaces for creating nests. As you begin cleaning up your yard and garden this fall, remember that these solitary bee species and many other beneficial critters rely on dead plant stems, fallen leaves, and other items that are often traditionally removed from the landscape.

dead plant stalks with new growth emerging at the base
Leave perennial plant stalks standing for the winter. Photo: C. Carignan

According to Colorado State University’s factsheet, Attracting Native Bees to Your Landscape, 90% of native bee species found around the world are solitary. Approximately 70% nest underground in the soil and about 30% nest inside hollow stems of plants and in tunnels left by other insects. Solitary female bees are responsible for collecting food, usually pollen, to include with each egg that she lays throughout the spring and summer. These eggs hatch into larva that spend the winter as pupa, which then turn into adults the following spring. Adult females die with the first fall frost. So in order to continue their life cycle, it is very important that their nesting sites are not destroyed in the fall.

To create friendly bee nesting habitats, provide dead wood like tree stumps or firewood for wood boring bees, plants with hollow stems (brambles and other perennials) for bees that need a tunnel-like structure, and areas of full sun, bare (un-mulched) soil, which ground nesting bees use for their nests.  Landscape fabric prevents ground-nesting bee’s ability to tunnel into the soil.

bee nesting box
Bee nesting box. Photo: Pixabay

Bee houses have gotten some attention in recent years and there are mixed messages about adding bee housing structures. Some evidence suggests that if not properly maintained, these well-intended additions could actually create a negative effect on populations. The houses provide a nice nesting area that results in large numbers of larva/pupa congregated close together, which could be easily targeted by predators, diseases, or parasites. For guidance on bee house maintenance check out this great factsheet from the Xerces Society.

Remember our unseen friends this fall and leave some of your plant materials in place to provide nesting and sheltering sites. Sit back, relax, and delay some of those cleanup chores until spring!

By Ashley Bodkins, Senior Agent Associate and Master Gardener Coordinator, Garrett County, Maryland, edited by Christa Carignan, Coordinator, Home & Garden Information Center, University of Maryland Extension. See more posts by Ashley and Christa.