Houston, TX

Houston sits in USDA zone 9b, where winter lows average 25–30°F. The last spring frost typically arrives February 13, and the first fall frost doesn't emerge until December 9, yielding a 300-day growing season. The defining constraint here is summer heat and humidity. Daytime highs consistently exceed 90°F from June through September, and humidity remains high even in spring and fall. This climate strongly favors heat-loving crops: figs, Asian persimmons, pomegranates, jujubes, and goji berries thrive with the long, hot summers that would severely stress temperate-zone favorites. Tomatoes and peppers do well, though sustained temperatures above 95°F in mid-summer can reduce fruit set and increase blossom-end rot. The high humidity creates consistent fungal disease pressure year-round, particularly powdery mildew, leaf spot, and root diseases in poorly drained soil. An advantage of the extended growing season is the ability to plant tender crops after February 13 and harvest them well into December before the first frost. The key to success here is embracing heat and choosing varieties selected for drought and humidity tolerance.

Houston's humidity drives consistent fungal disease pressure. Powdery mildew, leaf spot diseases, and anthracnose thrive in the warm, moist conditions common from spring through fall. Many gardeners plant tomatoes expecting the long growing season to yield abundant harvests, but sustained temperatures above 95°F in July and August trigger pollen sterility and blossom-end rot, cutting yields sharply. Peppers tolerate heat better but still struggle during the most intense weeks. Heavy clay soil is common in the area, and poor drainage in rainy periods, particularly in spring and early summer, accelerates fungal infections and root rot. Early-season crops planted after the February 13 frost can occasionally succumb to unexpected late frosts that occur into March. Selecting disease-resistant varieties, improving soil drainage, and choosing heat-tolerant cultivars rather than standard temperate varieties is essential.

Plant heat-tolerant tomato and pepper varieties selected for high-temperature climates rather than standard northern cultivars. Varieties bred for the South and Southwest handle heat better and are often disease-resistant to Houston-area fungal threats. In February, tomatoes planted immediately after the last frost date (February 13) will set fruit well into spring before heat stress arrives. A second planting in July or August, after the most intense summer heat, can produce a fall crop as temperatures moderate in September and October. Apply 3–4 inches of mulch around trees and shrubs to keep soil cooler and reduce the splashing of fungal spores from soil to foliage during heavy rain. Drip irrigation or soaker hoses, paired with early-morning watering, keep foliage dry and reduce disease. Thin crowded growth in high-humidity areas to improve air circulation, particularly important in the humid Houston climate.