Houston, TX

Houston's gardening season is defined less by frost risk than by heat and humidity. With a last spring frost around February 13 and first fall frost not until December 9, the growing season stretches 300 days; this is longer than most regions in Texas. Frost is a genuine but infrequent constraint. The real gardening challenges are summer heat stress, fungal diseases thriving in humid conditions, and choosing varieties that prosper in subtropical conditions.

This long, warm season favors crops that love heat. Figs thrive in Houston's intense sun and heat. Pomegranates, Asian persimmons, jujubes, and goji berries all flourish where winters rarely drop below 25°F. Tomatoes are reliable when grown with heat-tolerant varieties; standard cultivars like 'Brandywine' often struggle. Hot peppers reach their full potential in Houston; sweet peppers require afternoon shade or variety selection to prevent flower drop in peak summer.

Spring comes early, with frost risk dropping to negligible after mid-February, but February itself remains unpredictable. Late February can still bring occasional cold snaps. Gardeners new to the area often lose early plantings to late winter freezes. By late February, soil temperatures are warming enough for succession plantings of warm-season crops through early summer.

Fall is nearly as productive as spring, thanks to the late December frost date. Cool-season crops (brassicas, greens, root vegetables) flourish from September through November and sometimes into early December.

The humidity is the trade-off: disease pressure is higher here than in drier parts of zone 9b. Variety selection and air circulation are non-negotiable.

Summer heat stress is the first common defeat. Pepper flowers drop in temperatures above 90°F if humidity is high and plants lack afternoon shade. Standard tomato varieties produce poorly when nighttime temperatures stay above 75°F (common July through August in Houston). Many cool-season crops simply won't germinate if soil temperature exceeds 75 to 80°F in summer.

Fungal diseases are the second challenge. Powdery mildew, leaf spot, and root rot thrive in Houston's humid conditions, especially if air circulation is poor. Overhead watering late in the day compounds the problem.

The third is late-winter frost. February is a deceptive month. Soil may be warm enough to plant, and daytime highs reach 70°F some days. Then a cold front pushes through, and temperatures drop into the 20s. Tender transplants set out in early February often die.

First, stagger tomato plantings. Start seeds indoors in late January for February planting, then again in mid-July for a fall crop. This sidesteps both the late-February frost risk and the midsummer heat slump when fruit set fails.

Second, plant heat-lovers in prominent spots. Figs, pomegranates, and jujubes thrive with minimal attention once established. Use afternoon shade (30 to 50 percent) for peppers in June through August to reduce flower drop while still ensuring enough light.

Third, treat fungal disease prevention as routine, not reactive. Water at soil level only, preferably in early morning. Choose disease-resistant varieties when available. Thin plants for air circulation. These habits prevent powdery mildew and leaf spot far more effectively than any spray.