Dig In: Garden checklist for week of May 30

Squash will grow quickly in high heat -- check the plants daily. Mulch helps keep the soil from drying out too fast, plus acts as weed control. (Photo: Kathy Morrison)

Take a break from planting and heavy-duty outdoor chores this Memorial Day weekend and instead concentrate on staying comfortable. That includes keeping your plants comfortable, too.

According to the National Weather Service, Sacramento will see its first triple-digit day of 2021 on Sunday, followed by a projected scorcher on Memorial Day – 106 degrees.

Fortunately, temperatures are expected to quickly cool down into the mid to low 90s. By next weekend, the forecast is back to 91 degrees, which is much closer to normal for the first week of June.

Average high for June in Sacramento is 87 degrees, but we can get much, much hotter; the record is 115.

When temperatures soar, plants slow down. Lawns barely grow, so mow less. Let the grass grow longer; the taller blades shade the roots, helping conserve moisture.

When the mercury hits 95 degrees, tomatoes may not set fruit. Citrus trees will self-thin and drop some of their baby oranges and lemons. Container plants can dry out very quickly.

On the plus side, this high heat wipes out powdery mildew. That fungal disease will stop in its tracks. Leaves already infected will drop off and be replaced by fresh foliage. Remember to clean up and discard those fallen leaves; otherwise, they may reinfect the plant once high temperatures cool back down into the 70s.

Concentrate garden chores in the early morning when the air is still cool. What needs attention this final weekend of May?

* Tie up vines and stake tall plants such as gladiolus and lilies. That gives their heavy flowers some support.

* Mulch, mulch, mulch! This “blanket” keeps moisture in the soil longer and helps your plants cope during hot weather.

* Avoid pot “hot feet.” Place a 1-inch-thick board under container plants sitting on pavement. This little cushion helps insulate them from radiated heat.

* Thin grapes on the vine for bigger, better clusters later this summer.

* Warm weather brings rapid growth in the vegetable garden; tomatoes and squash enjoy the heat. Deep-water, then feed with a balanced fertilizer. Bone meal can spur the bloom cycle and help set fruit.

* Generally, tomatoes need deep watering two to three times a week, but don’t let them dry out completely. That can encourage blossom-end rot

* Trim off dead flowers from rose bushes to keep them blooming through the summer. Roses also benefit from deep watering and feeding now. A top dressing of aged compost will keep them happy. It feeds as well as keeps roots moist.

* From seed, plant corn, pumpkins, melons, radishes, squash and sunflowers.

* Transplant summer annuals such as petunias, marigolds and zinnias.

* Transplant perennial flowers including astilbe, columbine, coneflowers, coreopsis, dahlias, rudbeckia, salvia and verbena.