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Help prepare plants to withstand rising temperature with a deep soaking

A layer of straw mulch will keep these heat-starved peppers moist when it gets hot.
A layer of straw mulch will keep these heat-starved peppers moist when it gets hot.

Can it really be true? As I write this, the forecast is for 90-degree temperatures for the weekend. After shivering and drowning through the spring, it is going to be a shock to get used to heat.

Our plants are going to be jolted by this sudden heat, too. Because of this, our plants are going to need some help to be ready to grow as it heats up.

Start by checking your sprinkler systems for plugged or broken heads. Most of us haven’t had to turn the systems on until very recently so there could be some last-minute maintenance to do. Give your plants a good deep soak during the first hot days. Well-hydrated plants will adapt to the heat faster.

If you have plants in containers, consider putting them on a drip system hooked to an automatic hose-end timer. Keeping container plantings well watered is the secret to helping them adjust to and survive the heat. Kits large enough to handle 10 pots or so are available online from various companies, including Lee Valley Tools for under $40. Battery-operated timers are available at any home center for under $30.

Once there is a good stock of moisture in the soil, mulch your flower and vegetable beds to keep it there. Almost any type of organic material can be used for mulch, including shredded pine needles and leaves, grass clippings that haven’t been sprayed with herbicide, straw (not hay, which has seeds in it) or commercial materials such as bark and compost. Put down a two- to three-inch layer and water it in. A nice benefit to mulching now is that it will block most of the weeds from coming up, and that will save you a lot of work through the best part of the summer.

If you haven’t fertilized plants that need it yet, do so now so there is food available to the roots as they begin to really grow. Keep in mind that many of the time-release fertilizers don’t activate until soil temperatures reach a consistent 70 degrees.

Now that we are getting into warmer weather, the effects of the three-day cold snap last October are becoming obvious. There are a lot of reports of seemingly healthy trees, shrubs and perennials dying after attempting to leaf out this spring or just not leafing out at all. While overall the winter was mild, when that streak of 15-degree days hit early in October, most plants hadn’t really started going dormant. They still had a lot of water in their branches and stems and it froze, damaging the cells that move water and food around the plant. This spring, the buds had enough reserves stored up to leaf out but no way to get water and food from the roots, so they withered quickly. There is nothing you can do to fix this except pruning out dead branches or replacing the plant.

Pat Munts is a Master Gardener who has gardened the same acre in Spokane Valley for 30 years. She can be reached by e-mail at


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