Plant Garlic, Collect Leaves, Control Leaf Pests

A key October task is planting garlic: It is essential to plant garlic where no plants in the onion family (garlic, onions, leeks, shallots) have been for at least 4 years. This year I received an all-time high number of questions (and sad photos) about garlic root diseases. This was undoubtedly due to the wet summer, which promoted common root diseases, but also due to the fact that a surprising number of folks had not been rotating their crops. The only management tool we have for soil borne diseases, including all kinds of root rot, is rotating crops to make sure dormant spores in the soil have time to die out before their host plants are grown there again. Along with that goes good sanitation practices: planting disease-free stock and destroying infected plants as soon as they are notices. A friend wondered if using disinfectants on garlic cloves before planting to kill root rot pathogens was necessary, but really there is no need for this. The pathogen spores stay in the soil after the crop is pulled, so disinfecting bulbs won’t help. And infected bulbs continue to deteriorate after harvest, so by the time you are ready to plant 3 months later, it will be obvious which ones you shouldn’t use. If the whole garlic bulbs are still crisp and healthy looking, with no sign mold or soft or discoloured tissue, plant cloves from those, but don’t plant healthy looking cloves if there were other cloves in the same bulb that look diseased.

This is the wrong time of year to spread manure or soluble fertilizers (nutrients, especially nitrogen, leach away in the winter rains), but you can enrich your garlic soil with finished compost because the action of micro-organisms in the composting process makes nitrogen less soluble. Also, if your soil pH is low, mix in agricultural lime before planting the garlic. Later on, when it gets cold, apply a thick leaf mulch to the garlic bed. And I always have to mention this: if garlic shoots poke up in mid-winter, don’t worry about it--they are very hardy and will be fine.

Rust reminder: If yours was one of the many gardens with Allium rust infections on leaves of garlic, leeks or onions this year there is one more precaution to take (see photos) The fungus that causes rust overwinters on living leaves, such as leeks, overwintering outdoors in the garden. SO it is important to get those leeks cleaned up and out of the garden well before the tips of garlic shoots appear to avoid spreading spores to the garlic. This was the first year I had rust on my leeks and garlic. Because garlic shoots sometime show as early as December, I am making sure every leek is harvested by the end of November (they will keep in the fridge for a month or two and can also be sauteed and frozen). Crop rotation is also important for managing this disease too since some dormant spores may be present in the soil, but the good news is that the rust isn’t on garlic bulbs so you can use your own garlic cloves to plant even if there was rust on the leaves.

Leaf chomping still going on: Right now the last generation of cabbageworms (velvety green caterpillars from those White Cabbage butterflies) is actively feeding, plus slugs and probably climbing cutworms are coming up at night too. Even earwigs are still chewing away on flower petals and tender leaves of spinach and lettuce. Either pick off the caterpillars or just leave them as they will be spinning chrysalises soon and that will be the end of the damage. Keep on using iron phosphate baits and ‘catch-and-stomp’ for slugs. After dark go out with a flashlight to look for climbing cutworms up on plants. The sooner you get rid of them, the less damage there will be all winter: there is only one generation a year and no more eggs and caterpillars will appear until next summer.

Look for Cutworms on Leaves After Dark

Collect leaves, leaves, leaves: You can’t do better than whole leaves for winter mulching so keep on raking and hauling these home. Poke them in and around plants until the soil is covered. Later, when the first really cold weather is forecast, lay a thick layer of leaf mulch right over the tops of the carrots, beets, celeriac and other root crops to protect the shoulders of the roots from frost damage. It isn’t a good idea to do this too early because it suffocates the plants and sometimes attracts rats and mice to burrow in the thick mulch.

Mulching for Winter, Garlic Bed in Foreground

Get a soil test: Now is a great time to get a pH test for your soil to find out whether or not you need to add lime to the soil. The testing labs are less busy and this is also the best time to apply lime to the garden (though it can be applied any time of year). Send or take your soil sample to an actual soil testing laboratory and don’t rely on kits or pH testers from the garden centre, which are not at all accurate. Brief instructions for soil sampling are on the MB Labs website and available from extension department on OSU or WSU web sites.

Stake plants: Keep on putting in stakes or using tomato cages to support plants easily toppled by high winds or heavy wet snow. This includes especially top heavy plants, such as Brussels sprouts, cabbage, broccoli. For tall trunks of Brussels sprouts, you may need substantial stakes. My huge plants survived yesterday’s storm but are looking a bit thrashed around so I will have to reinforce their supports. For smaller plants, 3 or 4 bamboo stakes around the stem of each plant works well. To work a tomato cage over smaller plants, such as winter broccoli or cauliflower, wrap the plant in a tea towel to pull the leaves in together and then slide the tomato cage down over the plant.

Brussels Sprouts Need Sturdy Supports for Winter

Band trees: Mid-October is when to put sticky bands on trees for Winter Moth. IF you saw a lot of small green caterpillars feeding in oak, apple and other deciduous trees last spring, protect your trees this year by trapping the female moths as they walk up the tree to lay their egg on tree branches (this works because the female moths can’t fly). For details on banding, see last year’s October 8 message.

Keep on trapping SWDs: Just like last year, it was early September before the spotted wing Drosophila showed up in large numbers in my garden, but now I am catching around 100 per day in my one vinegar trap. Last winter I trapped SWD all winter, catching over 3000 adults by early February (the previous year I had caught 6000 by that time!). Just leave a trap out all winter, periodically dumping out the mess and changing the vinegar. For what SWD looks like in the vinegar see. For instructions on how to make a simple trap, see my June 14, 2016 message. By eliminating the adults in the local area around your garden over the winter, it undoubtedly delays the date when the numbers start to climb later in the season.

October 14, 2020 1:40 PM

Community Comments

  • Avatar Peter says:

    Your comment on mulching garlic with lots of leaves is something I don't do anymore. Other crops and shrubery yes, but not garlic. I only mulch my garlic crop with canary grass. In the past, I found that a thick carpet of leaves only caused the young garlic shoots to weave and turn, this way and that, to get through to the light. The result being the new shoots were bent out of shape, stunted, and struggled to straighten out and strengthen. With canary grass or next best, second-cut, seedless straw, the young garlic grow straight and strong. That's my method. A little seaweed also helps. Peter