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In the Garden: Soil temperature, May duties

Plant bougainvillea in May for tropical color in your yards and gardens. Photo by Peggy Choucair

To state the obvious, soil is an important factor in gardening. Yes, we test nutrient levels and pH. Yet, there is another factor regarding soil that we haven’t discussed: temperature.

Bill Luedecke and daughter Martelle offer advice to Highland Lakes gardeners.

There are four labels of temperature range for soil: minimal, optimum, realistic, maximum. These ranges vary for plants. For instance, the optimum temperature for echinacea is 70-85 degrees, but the optimum temperature for chives is 60-75 degrees. You can find the optimum, or temperature range, on the back of seed packets.

If you started your seeds indoors and have already recycled your seed packets, a good general rule of thumb is 65(ish) degrees for transplants. For transplants, you want to check the temperature of the soil to 5 inches. Whether you are using a barbecue thermometer, Thanksgiving turkey thermometer, or a thermometer designed especially for testing soil temperatures, make sure the probe will reach 5 inches into the soil.


1. For fleas and ticks, our wonderful soldiers, the beneficial nematodes. When the ground is dry, apply diatomaceous earth. Sulfur works great for chiggers. Apply elemental sulfur at 4 pounds per 1,000 square feet.

2. Plant tropical color: allamanda, bougainvillea, hibiscus, mandevilla, and penta.

3. Warm-season annuals to plant: begonias, caladiums, cosmos, impatiens, lantana, periwinkle, and zinnias.

4. Perennials such as asters, cannas, gladiolas, mums, summer bulbs. Put some other fall perennials in the ground.

5. Don’t wash your hands yet. We can also plant hot-weather vegetables, any and all of the herbs. Hurry and get them in the ground so they can absorb all the rainwater that is falling.

6. Add to your compost pile and turn it.

7. Remember our avian friends. With this wet, wondrous weather we have been having, keep an eye on your bird feeders to make sure there aren’t stuck seeds molding because of the moist air.

8. Prune spring flowering shrubs, vines, and roses that bloom only in the spring.

9. DO NOT prune red or live oaks unless they are damaged. No oak wilt wanted.

10. Dead head flowering plants. Pinch off the top of a spent bloom and drop into the pot or ground for nutrients.

11. Fertilize with high nitrogen (or coffee/tea) your bougainvilleas.


Choosing plants can be confusing at times. What is the difference between annual and perennial? A flowering plant with the label “annual” will last for a season. Generally, it will grow quickly, bloom for its season, drop seeds, and expire. On the other hand, a “perennial” plant biologically prepares for the next year. While it also might bloom, a perennial plant uses some of its cells and energy to form overwintering buds, bulbs or tubers. When spring comes again, the buds, bulbs, or tubers emerge as stalks and leaves then flowers. Therefore, annual means for a year/season and perennials last for more than one (dependent on harsh weather conditions.)

Keep your souls and soles in your garden!

Remember the True Master Gardener: Jesus said, “I am the vine; my Father is the Gardener.” John 15:1

Contact Bill Luedecke at The Luedecke Group Realtors at (512) 577-1463 or email him at Contact daughter Martelle Luedecke at (512) 769-3179 or

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