Plant tomatoes in Houston between late February and mid-March for spring harvest, or in late July and August for fall harvest

Houston's warm climate means you can grow tomatoes twice a year, but the timing is different from most of the country. Spring tomatoes go in the ground when soil temperatures reach 60°F consistently—usually late February through mid-March. Fall tomatoes plant in late July through August, when the intense summer heat breaks and soil begins to cool. Planting outside these windows means your seedlings will either rot in cold soil or cook before they set fruit in peak summer heat.

The reason Houston has two seasons is frost. Your last spring frost typically falls between mid-March and early April, depending on your exact location in the metro area. Your first fall frost arrives around mid-November. That gives you a narrow window in spring before heat becomes extreme, and a longer window in late summer when temperatures drop enough for fruit to develop.

Key Takeaways

  • Spring tomatoes plant in late February to mid-March, after soil warms to 60°F but before the worst heat arrives in May.
  • Fall tomatoes plant in late July through August, when summer heat peaks but seedlings have time to mature before November frost.
  • Soil temperature matters more than air temperature—use a soil thermometer to check the ground, not just the weather forecast.
  • Houston's humidity and heat make disease management critical; choose varieties bred for hot, wet climates and space plants for air flow.
  • Transplants (seedlings started indoors) work better than direct seed in Houston because they establish faster before extreme heat or cold arrives.

Spring Planting: Late February Through Mid-March

Late February is when most Houston gardeners start their spring tomato season. Soil temperatures at this point usually sit between 60°F and 65°F—warm enough for seeds to germinate and roots to grow without rotting. If you are using transplants (which is faster and more reliable), you can plant them as soon as soil reaches 60°F. Check with a soil thermometer pushed 4 inches into the ground in the morning; air temperature can fool you, especially on warm days followed by cold nights.

Mid-March is your important date for spring planting in Houston. By late April, daytime temperatures regularly exceed 85°F, and by May they climb into the low 90s. Tomatoes stop setting fruit when nighttime temperatures stay above 75°F—which happens reliably by late May in Houston. If you plant in mid-March, your plants will flower and set fruit before that heat wall hits. If you plant in April, you will get foliage and few tomatoes.

Spring crops produce from May through June, then decline as heat intensifies. Most gardeners pull spring plants by July when disease pressure rises and fruit quality drops.

Fall Planting: Late July Through August

Fall planting opens in late July, when summer heat is at its worst but cooling is beginning. Soil temperatures in late July still hover around 80°F or higher, which is too hot for seed germination—seeds will sit dormant or rot. Start seeds indoors in June or early July in a cool location (a basement or shaded corner, not a sunny window), then transplant seedlings into the garden in late July or early August when they are 6 to 8 weeks old.

August is the safer month for fall planting because soil has cooled slightly and you have more time before frost. Transplants planted in early August will mature and produce from September through November, giving you a full three months of harvest before the first frost arrives around mid-November. Late August plantings still work but leave less margin for error if frost comes early.

Fall crops often produce better quality fruit than spring crops because humidity drops and disease pressure eases as temperatures cool. Many Houston gardeners consider fall their main tomato season.

Soil Temperature vs. Air Temperature

Houston's weather swings can be sharp. A warm day in February does not mean soil is ready—it may still be in the 50s. Conversely, a cool morning in late July does not mean soil has cooled enough for seed germination. A soil thermometer costs $10 to $20 and removes the guesswork. Push it 4 inches into the ground in the spot where you plan to plant, wait 2 minutes, and read the temperature.

For spring planting, wait until soil reads 60°F consistently over several days. For fall seed starting indoors, you do not need to check soil—just start seeds in a cool indoor space. For fall transplanting, soil can be warmer (70°F to 80°F is fine) because your seedlings are already established and can handle heat stress better than germinating seeds.

Choosing Varieties for Houston's Heat and Humidity

Not all tomato varieties handle Houston's climate equally. Heat-tolerant varieties like 'Phoenix', 'Heatwave II', 'Surefire', and 'Sungold' set fruit even when nights stay warm. Disease-resistant varieties matter too—look for letters like V, F, or N on the label, which indicate resistance to Verticillium wilt, Fusarium wilt, and nematodes. Houston's humidity creates ideal conditions for these soil-borne diseases.

Cherry tomatoes and smaller varieties often outperform large slicing tomatoes in Houston heat. They mature faster, set fruit more reliably, and handle disease pressure better. If you want large tomatoes, plant them in spring when heat arrives more gradually, giving them time to mature before peak summer.

Spacing and Air Flow to Prevent Disease

Houston's humidity means fungal diseases like early blight and septoria leaf spot thrive. Space plants at least 24 to 36 inches apart—wider than most guides recommend—to allow air to move between leaves and dry them after rain or morning dew. Prune lower leaves (the first 12 inches above soil) once plants are established to reduce soil splash and disease spread.

Water at the soil level, not overhead. Wet foliage in Houston's humidity is an invitation to disease. Drip irrigation or soaker hoses work best. Water early in the morning so any accidental leaf wetting dries quickly in the sun.

Hardening Off Transplants Before Planting

Whether you start seeds indoors or buy transplants from a nursery, they need to adjust to outdoor conditions before planting. This process, called hardening off, takes 7 to 10 days. Place seedlings outside in a shaded, sheltered spot for 2 to 3 hours on day one. Increase outdoor time by an hour or two each day, gradually moving them into more sun. By day 7 or 8, they should spend the full day outside. By day 10, they can stay out overnight if temperatures stay above 50°F.

Hardening off prevents transplant shock—the wilting and stunted growth that happens when seedlings go from a stable indoor environment straight into wind, sun, and temperature swings. In Houston, it also gives plants time to toughen up before heat or humidity stress hits.

Frequently Asked Questions

Can I plant tomatoes in January in Houston?

Soil is usually too cold in January—typically in the 50s. Transplants planted in cold soil will sit dormant and may rot before roots establish. Wait until late February when soil reaches 60°F. If you want an earlier start, begin seeds indoors in December and transplant outside in late February.

What happens if I plant tomatoes in April?

April plantings usually fail to set fruit in Houston. Temperatures climb rapidly, and nighttime lows exceed 75°F by late May, which stops flower and fruit development. You will get a large plant with few or no tomatoes. Spring planting must finish by mid-March.

Do I need to start fall seeds indoors, or can I direct seed in August?

Direct seeding in August usually fails because soil is too hot—seeds will not germinate. Start seeds indoors in June or July in a cool location, then transplant seedlings into the garden in late July or August. This gives you a 6 to 8 week head start before planting.

Which month produces better tomatoes in Houston, spring or fall?

Fall crops usually taste better and have fewer disease problems because humidity drops and temperatures cool gradually. Spring crops mature quickly but often suffer from heat stress and disease. Many Houston gardeners focus on fall as their main season and treat spring as a bonus crop.

What if frost comes early and kills my fall plants?

Early frost is rare in Houston but possible. Plant fall crops by early August to give them maximum time to mature before mid-November. If frost does arrive early, you will lose unharvested fruit, but plants planted by August usually produce enough tomatoes in September and October to make the season worthwhile.