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Gardener's checklist: Mid-summer

The corner of a house and deck with flowers in pots adjacent to a shady garden with a sunny lawn, garden bed and trees in the background

The heat is on and the gardening season is in full swing. No more threat of cold nights — we’ve had some real heatwaves — and we can turn our attention to caring for the plants we worried over in May. Our checklist today is lengthy.

Container care

Watering daily is most important for planted containers. Hopefully, we will get rain, but the long-term forecast shows drier than normal conditions.

Containers are most often planted with annuals like vegetables and flowers, but people are branching out and planting perennials and even woody shrubs like blueberries and hydrangeas in tier containers.

Fertilize your containers every 2 to 3 weeks, making sure the soil is saturated first with water (never fertilize a totally dry plant). Slow-release fertilizers can also be added to your containers to allow for a small amount of fertilizer to be released every time you water.

Many garden centers have plants at reduced prices now, so consider planting more containers or adding these to your gardens. — Julie Weisenhorn, Extension horticulture educator

Cover up that soil

If you find that you have a gap in your vegetable garden rotation, consider planting a summer cover crop. Sudden torrential downpours and high winds can occur during the next few months, and cover crops can help slow down erosion and nutrient loss.

Several options are available for gardeners, and plants such as buckwheat or lacy phacelia can be a powerful tool to bring in beneficial insects and pollinators. If you are looking to add tons of organic matter in a hurry and don’t mind a little bit of extra maintenance, take a look at sowing sudex (sudangrass or sorghum-sudangrass). — Shane Bugeja, Extension educator, Blue Earth and Le Sueur counties

Maintain your lawn

In Minnesota, we grow cool-season lawns. ​With current soil and air temperatures in Central Minnesota, it's time to stop seeding for now and to slow down regular lawn maintenance. Wait to re-seed until mid-August.

Start extending the time between watering. Healthy Kentucky blue and fine fescue grasses can tolerate a lot of heat and drought. If these conditions continue for more than a month, give your fescues 1/4 to 1/2 an inch of water. That will keep their crowns alive, and they will recover after the drought passes and temperatures start to cool. If you choose to sod, water, water, water until it's fully established.

Raise your mowing height to 4 inches or more if you can. This helps keep the soil cooler, keeps the grass from having to recover from mowing, and shades out those warm-season weed seeds. Check out the Home Lawn Care Newsletter. — Kim Sullivan, Extension Master Gardener

Wait to spray lawn weeds

To protect sensitive garden plants like peppers, tomatoes, and grapes, avoid spraying lawn herbicides during hot weather. The hotter the temperatures, the easier it is for lawn herbicides containing 2,4-D and dicamba to vaporize into the air and hurt garden plants. Wait until prolonged cool fall weather to spray. This is good news for those of us who would rather not load up a sprayer! — Annie Klodd, Extension fruit educator

Identify insect pests

If you see damage on your plants that you suspect (or know) is from an insect, try to figure out who the culprit is before you decide to use insecticides. Identifying your insect pest is an important step in proper management. Once you determine what kind of insect is causing damage, you can try to target that particular insect and be mindful to not harm beneficial insects and pollinators in your yard or garden.

Look for information about a specific insect’s life cycle or behavior that could be useful while you’re making management decisions. For example, you might decide to not kill a caterpillar if you discover that it’s going to turn into a butterfly soon, meaning that it won’t be munching on your plant for much longer.

iNaturalist is a good, free app for ID-ing insects, and there are several other online gardening apps that help with this as well. — Claire LaCanne, Extension educator, Rice and Steele counties

Japanese beetles

These insects arrive in late June or early July and stick around until mid-August or so. They are also strong fliers and can fly several miles a day.

It’s critical to start hand-picking beetles as soon as you see them as damage from a few beetles feeding attracts more beetles to your yard. When hand-picking them, drop or knock the beetles off your plants into a bucket of soapy water.

Stay away from the Japanese beetle traps as the pheromone in them will attract even more beetles to your yard. Japanese beetles in yards and gardens — Julie Weisenhorn, Extension horticulture educator

Vegetable care

Tomatoes are starting to set green fruit. You may find your early tomatoes have blossom end rot. Even if you have watered consistently and supplied plenty of nutrients, it's common for the first few fruits to have it. This is especially true in very hot weather, as the heat results in rapid cell division, leading the fruit to grow faster than the plant can get calcium to the new cells. If you're seeing more blossom end rot than usual, don't panic. Just remove the fruit with symptoms so the plant can put its energy into new, healthy fruit. See Growing tomatoes in home gardens.

Garlic scapes (the flower buds) are starting to appear, which means we are about 3 to 4 weeks out from garlic harvest. It's worth taking the time to remove the scapes (they are delicious sauteed in olive oil or butter), so the plant will put its energy into the bulb.

In these next few weeks, your garlic will size up considerably, and even moisture is important for good bulb development. Keep irrigating until at least 50% of the leaves have turned brown. See Growing garlic in home gardens. — Natalie Hoidal, Extension educator, local foods and vegetable crops

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