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Garden Tips

Gardening in the Heat of Summer – NOT!
By: Bob Beyer, Travis County Master Gardener

Here in Central Texas, summers are our most stressful season of the year – unlike our northern neighbors who declare winter to be their season of distress for gardeners. Temperatures from June through October can easily exceed 100 for long durations. Added to the strong sunlight intensity, low humidity, and peak drying conditions, gardening activities are stressful for the gardener and the plants! Here are some survival tips:

Hot temperature1. STOP FERTILIZING: With the exception of potted plants which lose nutrients every time they are watered (frequently in summer), most garden plants go into protective dormancy to survive the heat and drought of summer conditions in Central Texas. There are some that thrive on the high heat, but they are in the minority. Fertilizing during these stressful conditions encourages new growth which is the opposite of what the plant is trying to do during dormant periods. Most plants produce new growth in spring when temperatures are more moderate. If you have an organically enriched soil, there is sufficient nutrient to sustain all garden plants through summer.

2. STOP PRUNING: Like fertilizing, pruning encourages new growth when plants are struggling to grow. New growth wilts easily and draws energy away from root development. Fungus grows during hot and humid conditions and pruning opens wounds for them to enter. Prune spring flowering shrubs after blooming in late spring and summer flowering shrubs in fall.

3. STOP PLANTING: Oh, the garden looks so nice during spring through fall; the temptation is always there to add new plants during summer. But, the reality is that the survival rate of new plantings drops significantly in high heat. The additional transpiration that occurs in heat adds stress to the plants and if roots are not watered more frequently, insufficient water is available for transpiration. Bottom line - stresses occur on the plant that makes it susceptible to disease and fungus. Plantings should be done in spring for evergreen and fall for deciduous plants, when temperatures are moderate and there is sufficient rainfall to help a new plant get established. Any new planting requires almost a year to become fully established so you want to give them a good head start by planting during non-stressful periods.

4. STOP OVERWATERING: Yes, this sounds odd. One would think you could never provide enough water to outdoor plants during high heat summer periods. You can easily overwater plants in summer creating waterlogged soil that will squeeze out available oxygen in the soil and cause immediate harm to your plants. It depends on your soils composition. You need to water but in average organic, well-drained soils, frequency is more important than quantity. In xeriscape environments, a deep, less frequent watering –focused in the immediate area of the plant's roots – works best. If plants are persistently wilting, try pinching off some of the newer foliage to reduce transpiration stress. This is a good argument for use of xeriphytic native plants for drought-tolerant gardens.

5. CUT BACK ON MOWING: If you are struggling to maintain a lawn in hot dry conditions, cut back on mowing allowing your grass to remain taller than might be aesthetically pleasing. Raise cutting height to 3" or more. This protects roots from drying and conserves water. Better yet, reduce your lawn area and go more xeriphytic.

6. CUT BACK ON GARDENING CHORES: Help save the gardener as well as the plants! Have your garden construction work done before the heat hits, mulch heavily to prevent weed infestation and preserve ground moisture, and follow the previous advice. As plants go dormant during extremely hot summers, the gardener can go dormant as well. Oh yes, there are always a few things to do – weeds somehow find a way to defy all attempts to discourage them, but good planning can minimize your need to stress yourself during summer.

In Central Texas, we really have two dormant periods in the garden: winter and summer, the latter being the most extreme. Even in shady areas, plants feel the stress of heat and take protective measures to survive. The gardener needs to do the same. Protect your health as well as your plants. Drink plenty of water, take frequent breaks when working outdoors, then hibernate indoors after 10AM to Noon, depending on weather conditions.

©Zilker Botanical Garden,
Austin Area Garden Council