Should You “Close” Your Vegetable Garden in Autumn?

The vegetable gardening season is drawing to a close here in the North. Already, with the cooler nights, many plants have stopped producing. Others, preferring the cooler weather, carry on, but there’s an end to everything and eventually you’ll have to resign yourself to “closing your vegetable garden”!

Why Close Your Vegetable Garden?

If you’re a laidback gardener, like me, you don’t “close” your ornamental garden, leaving it to nature to decompose the dead leaves and stems that remain at the end of the season. Why close your vegetable garden?

Most publications and websites suggest removing plant debris from your vegetable garden at the end of the season by removing the entire plant, including roots, leaves and stems, leaving the soil bare. It is claimed that diseases and insect pests can overwinter in this debris and return the following season… That doesn’t sound very laidback to me!

Here’s Why I Leave My Plants in the Garden

Personally, I don’t do much tidying up in my vegetable garden in autumn. I leave all the plants in place: branches, leaves, roots, rotten fruit, everything! One of the only jobs I do is to collect and shred the dead leaves that fall on hard surfaces (patios, decks, etc.) and then cover my garden soil with them, where they serve as mulch, protecting my soil from leaching, erosion and temperature variations, while feeding my soil with organic matter.

The dead stems and leaves I leave in the garden provide a winter home for beneficial insects (and less beneficial ones, I grant you, but it all balances out in the end, doesn’t it?). Their roots protect the soil from erosion and provide a substantial supply of organic matter that will feed the soil’s flora and fauna, microscopic or otherwise, and eventually transform it into nutrients for fruit and vegetables. Organic matter also helps to structure the soil, allowing it to drain and store moisture, and providing oxygen to the roots, which need it to do their work.

Disturbing the soil is tantamount to destroying some of the microbial life in it. While there will always be some disturbance in the soil of a vegetable garden, it’s a good idea to minimize tillage to preserve as much microbial life as possible.

Disease and Pests

But what about the pests and diseases that plagued us this season? Will they be back next year? Probably yes, but there are several reasons why I’m not worried about that:

1. Many fungi, bacteria, diseases and insects will overwinter in the soil, whether I remove the plants or not. The notorious mildew, for example, returns year after year as its spores overwinter in the soil.
2. Even if I eliminate the affected plants, these problems persist in my environment: in my neighbors’ vegetable gardens, in ornamental beds, in parks, and so on. If it were possible to eradicate these insects and diseases, it would already be done!
3. I practice crop rotation. By changing where each type of plant is planted each year, the pests that survive in organic debris will have a hard time finding their prey, which will have moved on.

Please note! It’s hard to generalize about all the problems that occur in the garden, and I don’t have the space here to describe them all ( a whole book could be written on the subject). If you want to know for sure, for every disease or pest you’ve had in your garden, check to see if it’s overwintering in the dead plants or in the soil or somewhere else. If you wish, remove the plants that harbor those pests.

Tolerance Levels

For my part, I have a very high degree of tolerance for this kind of problem and for imperfection in the garden in general. If a plant is affected by a disease or an insect, I rarely intervene. I prefer to stick to fruits and vegetables that have few problems and do well here.

We all have different conditions and degrees of tolerance. I totally understand people who have large gardens and need them for food. Perhaps they want to take diseases and insects more seriously than I do. I still strongly suggest using organic mulch or cover crops, rather than leaving the soil bare. Be aware, however, that despite all the interventions we can make, diseases and pests will return.

Needless to say, this advice does not necessarily apply to small- or large-scale farmers whose production conditions differ from those of a home garden, and whose income depends on it.

Composting the Debris

If you decide to dispose of infected plants, remember that the majority of insects and diseases will be destroyed during the composting process… if it’s done properly, of course!

When a compost pile is made properly, with the right ratio of brown to green (nitrogen/carbon) and is the right size, the decomposition process will create enough heat to kill off most harmful infections. However, if you don’t take your composting seriously enough (which I often do, laidback as I am!), your pile won’t get hot enough and some diseases and insects may survive. You’ll then spread them everywhere you put your compost, aggravating the problem.

Another option would be to put this infected debris at the back of an ornamental bed, where it won’t affect your vegetable garden, as long as it’s at a safe distance. This way, you won’t have to throw away this organic material, and it will be useful for other plants.

Other Solutions

So, if eliminating organic debris from our garden doesn’t stop diseases and insect pests from spreading, what do we do? First, the easiest thing to do is to eliminate the problem at source. By choosing disease- and pest-resistant seeds, you’ll reduce, but not necessarily eliminate, the problems.

I’m of the opinion that having a diversified vegetable garden, with several types of fruit and vegetables, but also flowers or perennials, will attract a diverse fauna, including beneficial insects that will help suppress harmful ones. What’s more, this diversity of plants will ensure that when one crop is affected, another won’t be, and the scent of certain plants can mask those of your crops from predators or attract them away.

In the case of vegetable plants that are severely infected for several seasons in a row, it may be time to take a break for one or more years to allow the disease to dissipate, or for the insect responsible to disappear, no longer having a host.

Insect netting is another ecological solution for protecting your crops from certain insect pests. By placing a net over your crops, insects such as cabbage worms, lacewings, carrot flies, leek moths and more, won’t be able to eat or lay their eggs on your crops. Don’t forget to remove the netting on plants that require pollination, such as cucumbers, squash and melons, when the flowers bloom. Normally, it will be too late for the beetle to seriously damage your plants after this time.

What’s Left to Do?

Laidback gardeners have little to do in autumn, whether in the vegetable or ornamental garden. But there are a few things you can do before winter arrives: clean and tidy up tools, hoses and pots, empty gutters, shred and store dead leaves (or not!), and so on. Read Larry Hodgson’s No-Hassle Fall Garden Care, to find out more.

With the time you’ll save by leaving your dead plants in place, why not expand your vegetable garden, plant bulbs or simply take a walk in the forest to enjoy the fall colors?