Houston, TX

Houston sits in zone 9b with a distinctly long growing season and a heat-defined climate. The last spring frost arrives February 13, relatively early, but atmospheric conditions in March and early April can still dip below freezing on clear nights. This is a common gotcha for gardeners who plant tender annuals too early. The first fall frost doesn't arrive until December 9, which means summer heat dominates from May through November. Winter lows range from 25 to 30°F, cold enough to kill tender perennials and tropicals but mild enough that many evergreens survive unprotected.

Heat and humidity define Houston gardening more than cold. Afternoon thunderstorms in summer dump water unevenly; some neighborhoods flood while others stay dry. The combination of warmth, moisture, and seasonal consistency makes Houston ideal for heat-loving fruit trees such as figs, pomegranates, jujubes, and Asian persimmons. These might only set reliable crops in zone 9b's warmer extremes. Warm-season vegetables including tomatoes and peppers thrive in Houston's extended season, though the transition from spring to summer often compresses the mild window where these plants flourish.

The dominant constraint is not cold but sustained heat coupled with humidity. Most Houston gardeners do their heavy planting and pruning work in fall (September through November) and spring (February through March) when afternoon temperatures stay below 90°F. Summer becomes maintenance mode: watering, pest watch, and protecting plants from UV scald.

Late spring freezes in March and early April catch gardeners off guard. The February 13 frost date lulls some into planting tender annuals too early. A clear night in late March can blacken young tomatoes and pepper transplants. More seasoned gardeners wait until mid-April.

Summer fungal diseases, especially powdery mildew on fruit trees and rose black spot, thrive in Houston's humidity. The afternoon thunderstorms that cool things down also create the wet leaf conditions fungi love. Fig trees and pomegranates suffer from anthracnose in high-humidity years.

Afternoon summer heat, often 95 to 100°F, wilts even established trees if irrigation lags. Shallow watering encourages surface roots. Running soaker hoses or drip lines early morning, before heat builds, prevents stress. Many home gardeners underestimate Houston's summer water demands despite the reputation for rain.

1. Plant warm-season crops after mid-April, not late February. Though the last frost is February 13, Houston's true warm-season window opens six weeks later when soil temperature stabilizes above 60°F and night lows hover consistently above 50°F. Tomatoes, peppers, and other heat-demanding crops planted before mid-April often stall in cool soil and become targets for early-season fungal issues.

1. Perform major pruning and shaping of fruit trees in late August through October, before the growing season resumes. Cool-season work is less stressful than summer pruning, which opens trees to sunscald injury when stripped of protective canopy in Houston's intense sun.

1. Install drip irrigation or soaker lines on permanent plantings. Houston's summer heat is sustained and intense enough that hand watering misses deep hydration. Set timers for pre-dawn watering to minimize mildew pressure and reduce water loss to evaporation.