The month of June is the midpoint of the year when spring ends and summer begins. Daylight increases as the calendar inches closer to summer solstice, the air temperature steadily rises and soil should be warm enough to transplant seedlings.
During June, it’s important to investigate the garden for weeds, plant diseases and pests. Weeding is a critical gardening tasks that we should attend to, because weeds compete with plants that produce desirable flowers, vegetables and fruit. Weeds can cause problems for the plants we’re cultivating by stealing nutrients, harboring detrimental pests and obstructing airflow. For more information on how to control weeds in home gardens or identifying a weed, please explore the resources below.
When pulling weeds from the garden, it’s the perfect opportunity to inspect plants for diseases. Common signs of disease are black spots on fruit, unusual plant color, leaf spots and wilt. If you see signs of mildew on a plant (e.g., bee balm, peony), a thick layer of mulch at the base of the plant can prevent mildew spores from splashing onto your plant during a shower. It’s important to catch these kinds of problems early because they may negatively affect healthy plants. If you need assistance determining what’s wrong with your plant, you can contact a U of M Extension Master Gardener in the county where you reside (links below).
You may witness insects in the garden on flowers or edible plants. Some insects can ruin garden plants, others help pollinate plants and others prey on problem insects. If you see holes in leaves, inspect the underside of the leaf—the insect culprit may be hiding there. It's important to distinguish garden pests from beneficial insects so you can decide if any action is needed. Examples of insects that can damage plants are the imported cabbageworm moth, the cabbage looper moth, the fourlined plant bug and the cucumber beetle. You can reduce some pest populations by planting companion plants next to certain edible plants that emit smells that repel the pests (e.g., onions, nasturtiums and thyme can repel the cabbage looper and imported cabbageworm). Cosmos, caraway or yarrow planted near pepper plants can attract lacewings, whose larvae prey upon scales, aphids, mites and mealybugs. The same plants attract ladybugs, which can help control mealybugs, whiteflies and aphids. Another beneficial insect is the assassin bug, which feeds on caterpillars, leafhoppers and Japanese beetles. Planting herbs such as dill and fennel (and perhaps marigolds) may entice them. Herbs such as rosemary, thyme or mint act as cover for ground beetles, which is mainly a nocturnal predator and feeds on garden slugs and a wide variety of pests. Ground beetles will lay eggs under protected shady areas.
In conclusion, if you stay on top of weeding, watch for plant diseases and fungi and learn to identify pests that are harmful (distinguishing them from beneficial insects), you can hopefully stay ahead of common garden problems or put your mind at ease if you discover that pest damage is cosmetic rather than fatal.
To help identify a problem or learn more strategies for dealing with pests, you may utilize the Extension Master Gardeners’ diagnostic services (link below).
Sources of Information
Diagnostic Services: https://www.ramseymastergardeners.org/diagnostic-services
To join a class, go to: https://www.ramseymastergardeners.org/classes
Control weeds in home gardens: https://extension.umn.edu/planting-and-growing-guides/controlling-weeds-home-gardens
Identify a weed: http://apps.extension.umn.edu/garden/diagnose/weed/
Plant diseases: https://extension.umn.edu/solve-problem/plant-diseases
The Kitchen Garden, by Alan Buckingham, DK, 2019, pp. 118-119. Plant diseases.
How to identify a moth: https://extension.umn.edu/yard-and-garden-insects/caterpillars-cole-crops
Beetles feed on weed seed: https://www.sciencedaily.com/releases/2011/07/110725101231.htm
Companion planting and trap cropping vegetables: https://extension.umn.edu/yard-and-garden-news/companion-planting-and-trap-cropping-vegetables
Benefits of companion planting: https://blog.southernexposure.com/2017/04/7-benefits-of-companion-planting/
Problems with plants: http://apps.extension.umn.edu/garden/diagnose/plant/
Ask a Master Gardener in your county: https://docs.google.com/spreadsheets/d/1idNywJQsOKurWeUFeDYYjr3zU4Km1aIyLmN-xEqZL8I/edit#gid=1248452618
Garden Q&A Live: https://www.ramseymastergardeners.org/garden-qa-live
Writer Biography: Justin McVean enjoys learning about global cuisines, is a graduate from culinary school, and is an avid abstract painter. He has been with the U of M Extension Master Gardeners since 2019.